# Ten Years of Basic Energy Sciences Accomplishments

Provided below are vignettes of some significant Basic Energy Sciences
(BES) program accomplishments from FY 1997 through FY 2006. These brief
accounts appear in the BES sections of the President's FY 1999 through
FY 2008 Budget Requests to Congress, respectively. The selected program
highlights are representative of the broad range of studies supported in
the BES program.\
\
**Selected FY 2006 Scientific Highlights/Accomplishments\
\
Materials Sciences and Engineering Subprogram\
**

-   ***Nanofluidic transistor*.** Imagine a valve to precisely control
    the flow of liquids but with dimensions so tiny that only one
    molecule at a time can pass through it. Controlled flow of ions in a
    liquid was recently demonstrated through very small nanochannels
    barely large enough to pass large molecules. Named "nanofluidic
    transistors," the nanochannel assembly functions in a way similar to
    ordinary transistors where the flow of electrons can be regulated by
    applying a voltage. Demonstrations were carried out on a
    35-nanometer channel constructed between two silicon dioxide plates;
    the channel was filled with water and potassium chloride salt. The
    flow of potassium ions could be completely stopped by applying an
    electric current across the channel. The regulation of the flow (or
    current) of charged molecules was also demonstrated. This exciting
    discovery now makes possible detection and separation of individual
    molecules in a fluid. Among the important implications of this
    discovery are advanced nanoscale chemical analysis with extreme
    sensitivity and the capability of sorting individual molecules.

-   ***Unexpected spontaneous reversal of magnetization in nanoscaled
    structures*.** New and unexpected magnetic phenomena have been
    discovered in ultrathin bilayers of ferromagnetic and
    antiferromagnetic films. Ferromagnetic materials (e.g., iron) have a
    positive magnetization due to the alignment of the magnetic moments.
    Antiferromagnet materials (e.g., nickel oxide) have no net
    magnetization due to the anti-parallel alignment of the magnetic
    moments. In bulk magnetic materials, regions of aligned magnetic
    moments, termed magnetic domains, are expected to align with an
    external applied magnetic field. The magnetic strength is determined
    by the degree of alignment of the magnetic domains. In contrast to
    naturally occurring bulk magnetic materials, an ultrathin
    ferromagnetic layer in close contact with an antiferromagnetic layer
    will spontaneously align *opposite* to the applied magnetic field
    upon cooling. The close proximity of the two different layers also
    results in an increase in magnetic strength. The ability to control
    and detect the magnetic alignment in ultrathin magnetic materials
    could lead to new concepts in computer data storage design. The
    fundamental understanding of the unexpected phenomena may also
    influence future research and development of magnetic based
    biological and chemical sensors.

-   ***Nano-electronic hydrodynamics and turbulence*.** Electrons moving
    across a nanometer-sized wire have been found to behave
    hydrodynamically, i.e., like a liquid flowing from one bucket to
    another through a small opening. This behavior is exactly contrary
    to expectations from a quantum mechanical prediction, and it has
    prompted theoretical predictions of new phenomena. Most striking is
    the prediction of possible turbulent electrical transport with eddy
    currents in nanoscale conductors that could seriously limit current
    flow. Such turbulent currents could then lead to extremely high
    electronic temperatures due to the "friction" of the electrons as
    they move against each other, resulting in potential premature
    failure at much reduced current flow. Experiments are being carried
    out to test these theoretical developments.

-   ***Using bioinspired methods to synthesize and assemble
    materials*.** Biological systems are renowned for synthesizing
    inorganic materials under mild conditions and assembling them into
    exquisitely shaped structures with high precision and control.
    Recently, by emulating the underlying chemistry and approaches of
    biology, several inorganic materials have been synthesized under
    mild conditions (room temperature, neutral pH, etc.), with a
    potential for significant energy savings in their large-scale
    manufacture. Some of the materials synthesized include
    semiconducting titanium dioxide, gallium oxide, and zinc oxide for
    solar energy conversion; ferroelectric barium titanate nanoparticles
    for energy storage; magnetite nanoparticles for ultra-high density
    magnetic information storage; and nanocrystalline palladium for
    hydrogen storage. Furthermore, by exploiting the ability of
    biological macromolecules (e.g., DNA, proteins, viruses) to
    self-assemble into large, well-defined structures and to nucleate
    the growth of inorganic materials, researchers have shown that
    complex electronic circuit elements and large ordered arrays of
    nanoparticles can be assembled with a precision that far exceeds the
    current top-down fabrication capabilities.

-   ***Unveiling the superconductor mystery*.** Understanding the
    phenomena of superconductivity and its mechanism has been among the
    most challenging issues facing the condensed matter and materials
    physics communities. The mystery of superconductivity is being
    tackled by a concerted effort, coupling synthesis and
    characterization with theory, modeling, and simulation. The recent
    discovery of superconductivity in actinide- and boron-containing
    materials indicates superconductivity may exist in many material
    systems yet to be discovered. The search for new materials is
    augmented by sophisticated techniques to modify the electronic
    properties of known superconducting materials, both chemically and
    electrically. Advances in new characterization tools, including
    proximal probes, have made possible the discovery of new phenomena,
    including competing phases within the superconducting phase. First
    principles calculations assisted by generalized density functional
    theory enabled accurate predictions of the electronic structure of
    superconducting materials. When coupled to an electron pairing
    mechanism, numerical models are being developed to predict the
    superconducting transition temperature as a first step towards a
    priori design of new superconductors.

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-   **Chemical Sciences, Geosciences, and Energy Biosciences Subprogram\
    \
    *Measuring the ultrafast motion within a molecule using its own
    electrons*.** Modern ultrafast lasers make it possible, in
    principle, to follow in real time the motions of the atoms that
    comprise a molecule. However, optical lasers are only indirect
    probes of atomic motion. This problem will be alleviated with the
    advent of the world's first x-ray free-electron laser, the Linac
    Coherent Light Source (LCLS), since x-rays allow direct tracking of
    atomic positions. Until the LCLS is available, optical laser pulses
    can be used in clever ways to track atomic motion in molecules. In
    one recently demonstrated example, the molecule's own electrons are
    used as the probe of atomic motion in a highly excited molecule. The
    electric field from an intense, optical laser pulse initially pulls
    electrons away from the molecule and then accelerates them back
    toward it. The highly energetic electrons scatter from the molecule.
    Rather than measure the scattered electrons, as might be done in an
    electron diffraction experiment, the new method exploits another
    phenomenon that is particularly sensitive to atomic motion. When the
    electrons re-collide with the molecule, they emit x-ray radiation in
    a process known as high-harmonic generation (HHG), and it is these
    x-rays that are detected. The wavelength of the re-colliding
    electrons is comparable to distances between atoms in a molecule;
    thus, the HHG x-rays emitted are highly sensitive to atomic motion
    within the molecule. This new method shows great promise as a way of
    imaging energetic molecules undergoing ultrafast structural
    transformations, including the fundamental action of all of
    chemistry, and the making and breaking of chemical bonds.

-   ***Sunlight-driven transformation of carbon dioxide into
    methanol*.** The first step in the chemical transformation of carbon
    dioxide into a transportable fuel such as methanol involves the
    interaction of light with a catalyst in a process known as
    photocatalysis. It has long been known that the photocatalytic
    formation of methanol from carbon dioxide can be initiated by
    high-energy ultraviolet radiation. Recent work has demonstrated that
    the critical first reaction that splits carbon dioxide into carbon
    monoxide and a free oxygen atom can also be triggered with visible
    light. This advance makes it feasible to consider harnessing
    sunlight to drive the photocatalytic production of methanol from
    carbon dioxide. The key to the new advance is to perform the initial
    photocatalytic reaction on the walls of the nanometer-sized channels
    of a porous silica solid through the excitation by visible light of
    a bimetallic catalyst. The energy from the absorption of light
    causes an electron to transfer from one metal in the catalyst to the
    other and subsequently activates the gaseous carbon dioxide to
    eliminate an oxygen atom to yield the carbon monoxide product.
    Various combinations of metals are now being explored with the goal
    of designing a complete and sustainable system to produce methanol.

-   ***Catalytic synthesis of alternative fuels and chemicals*.**
    Current manufacturing technologies for fuels and chemicals are often
    inefficient. The need to dramatically improve efficiency in fuel and
    chemical production is motivating the search for new chemical
    pathways using new catalysts tailored to guide chemical reactions
    with precision toward a selected product without wasteful
    sub-products. Recent approaches enlist different catalysts to
    cooperate in parallel to transform molecular intermediates.
    Sometimes referred to as tandem catalysis, this approach can
    potentially yield ultrahigh selectivity. An example is the venerable
    Fisher-Tropsch production of diesel fuel from carbon monoxide and
    hydrogen. Model catalysts for this polymerization reaction are
    typically unselective and yield a mixture of hydrocarbons or
    alcohols with carbon-chain lengths varying over a wide range. For
    minimum energy consumption and maximum yield, the ideal process
    should provide a very narrow carbon-chain range. Two recent advances
    may rejuvenate the Fisher-Tropsch process: the discovery of
    efficient metathesis catalysts, which led to the Nobel Prize in
    Chemistry for 2006, and the selective activation of carbon-hydrogen
    bonds. Two catalysts are necessary to carry out these two very
    different functions simultaneously on the same growing polymers. The
    carbon-hydrogen activation catalyst limits the yield of low-end
    hydrocarbons, and the metathesis polymerization catalyst
    simultaneously controls the high-end hydrocarbons. This can
    potentially lead to an ideal diesel-oil without the need for
    energy-intensive separations. This new tandem catalysis application
    is being followed intensely by researchers worldwide for its
    potential to revolutionize the science of alternative fuels and
    chemicals synthesis.

-   ***Carrier multiplication: a possible revolutionary step toward
    highly efficient solar cells*.** In a normal solar cell, a single
    photon from the sun is converted into a single carrier of electrical
    current (an electron-hole pair) in a bulk crystal material called a
    semiconductor. This process is inherently inefficient because much
    of the energy of the solar photon is wasted as excess heat in the
    semiconductor. Recent experiments on the interaction of photons with
    nanocrystalline samples of semiconductors have demonstrated a
    remarkable effect, known as carrier multiplication, in which a
    single photon creates multiple charge carriers. Recent work has
    demonstrated that as many as seven charge carriers can be created
    with a single photon and that the process is universal, i.e., it
    occurs in all types of nanocrystalline semiconductors. These new
    results suggest that nanoscale confinement plays an important role
    in the carrier multiplication mechanism, which is now thought to be
    an instantaneous excitation of multiple electrons by a single
    photon. Critical issues must be addressed before an operational
    solar cell based on carrier multiplication can be created, such as
    separating and harvesting the charge carriers to create electrical
    current. However, present estimates of the conversion efficiency for
    a solar cell based on carrier multiplication are as high as 50
    percent, which is about twice that of the best solar cell in current
    operation. Doubling solar cell conversion efficiency would represent
    a revolutionary advance in our ability to harness renewable energy
    from the sun.

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-   ***Visualizing chemistry: the promise of advanced chemical
    imaging*.** The emerging possibility of "chemical imaging" is
    transforming the way scientists follow the chemical transformation
    of molecules on surfaces, within cells, or immersed in other complex
    environments. Chemical imaging is the term given to a set of
    experimental techniques that use photon beams, electron beams, or
    proximal electromechanical probes to track molecules in two- or
    three-dimensional space and real time, while keeping track of
    chemical identity and even molecular structure. In the ideal limit,
    chemical imaging means nanometer spatial resolution, femtosecond
    temporal resolution, and "fingerprint" recognition of the molecular
    mass and structure. As a recent example, researchers are using
    focused laser beams (space and time information) coupled with mass
    spectrometry (chemical identification), to track specific
    metabolites in functioning cells. Multiplexing the mass information
    allows the simultaneous mapping of several species. Understanding
    the metabolic transformation of important biomolecules in cells is
    the first step toward influencing them in service of improved
    biochemical processes. Other examples include the use of chemical
    imaging to examine single-site catalysts as they influence reactions
    on surfaces and light-harvesting "antenna molecules" that are key
    participants in photochemical charge-transfer processes.

**Selected FY 2006 Facility Accomplishments**

-   **The Advanced Light Source (ALS) at LBNL**

    *Experiments begin on new femtosecond X-ray beamline*. Experiments
    using ultrafast soft x-rays began in FY 2006 on Beamline 6.0.1.2.
    High-resolution x-ray spectroscopy and diffraction at photon
    energies from 150--1800 eV are now possible using the new,
    high-brightness, in-vacuum-undulator beamline, which increases the
    flux by a factor of 1000 relative to its predecessor. Beamline
    6.0.1, a complementary hard x-ray beamline using the same insertion
    device and extending the photon energy available to users from
    2.2--10 keV, was also installed, and its commissioning was begun. In
    the first measurements, soft x-ray pulses of 200-femtosecond
    duration were used to study phase transitions in vanadium oxide.

-   **The Advanced Photon Source (APS) at ANL**

    *Record nanofocusing with an innovative lens design*. A new device,
    the Multilayer Laue Lens, developed at Argonne National Laboratory
    jointly between the APS and the Center for Nanoscale Materials, has
    set a world\'s record for line size resolution produced with a hard
    x-ray beam. The wafer from which the device was made won a 2005 R&D
    100 award, given to the world\'s top 100 scientific and
    technological innovations. Enhancements to the device have now
    increased its ability to focus the x-rays with an energy level of
    19.5 keV to less than 20 nanometers. Using the lens, researchers
    will be able to visualize three-dimensional electronic circuit
    boards to find circuit errors, map impurities in biological or
    environmental samples at the nanometer scale, or analyze samples
    inside high-pressure or high-temperature cells because hard x-rays,
    unlike soft x-rays, are able to penetrate container walls. This
    device has potential for a multitude of uses, including possible
    incorporation at the nanoprobe beamline at APS associated with the
    Center for Nanoscale Materials facility.

-   **The National Synchrotron Light Source (NSLS) at BNL**

    *Novel undulator design developed and installed*. A custom-designed,
    cryogenic-ready, in-vacuum, miniature-gap hybrid undulator has been
    installed in the X25 straight section of the NSLS x-ray ring. The
    new radiation source, the first of its kind, will be an order of
    magnitude brighter than the original wiggler. By cooling the magnet
    array, this insertion device can have a higher magnetic field and a
    higher radiation resistance, resulting in a larger photon energy
    tuning range. Consequently, unlike previous miniature-gap undulators
    in use at the NSLS, this new undulator will be continuously tunable
    from 2 to 20 keV by employing all harmonics up through the 9th. This
    upgrade will provide significant benefits to the macromolecular
    crystallography program at the NSLS. This technology will be useful
    to all medium-energy storage rings in the world.

-   **The Stanford Synchrotron Radiation Laboratory (SSRL) at SLAC**

    *Operation at high current of 500 mA*. The SPEAR3 accelerator
    reached its design current of 500 mA for the first time during a
    special run last year. Under similar test conditions, a selected
    beam line (BL 6) was subsequently operated successfully at 500 mA to
    test the performance of newly designed optical components, including
    the liquid-nitrogen-cooled double crystal monochromator. The success
    of this test paves the way for commissioning the other beam lines.
    The SPEAR3 accelerator received permission to operate routinely at
    500 mA following an extensive accelerator readiness review.
    Authorization for operating beam lines for users at 500 mA is
    expected during the FY 2007 user run, when selected time periods
    will be allocated to commission, characterize, and operate beam
    lines at high current. SSRL is planning to operate full time with
    high current in FY 2008.

-   **The Spallation Neutron Source (SNS) at ORNL**

    *Commissioning and initial instrument results*. Construction and
    commissioning of the Spallation Neutron Source, an accelerator-based
    neutron source that will provide the most intense pulsed neutron
    beams in the world for scientific research and industrial
    development, was completed, and the facility began operations in
    late FY 2006. The backscattering spectrometer that is part of the
    initial suite of instruments has unprecedented dynamic range and an
    energy resolution of better than 3 x 10^-6^ electron volts. Initial
    operation of this hardware involved test measurements of excitations
    in picoline (a hydrocarbon), which confirmed the performance of the
    instrument.

**Selected FY 2005 Scientific Highlights/Accomplishments\
\
Materials Sciences and Engineering Subprogram\
**

-   ***Synchrotron X-Rays Demonstrate Nanoscale Ferroelectricity.***
    Films only a few atoms thick have been made that retain the
    controllable electric polarization needed for next generation
    nanoscale devices. Such ultrathin ferroelectric films have the
    potential to revolutionize future electronics, sensors, and
    actuators. Previous studies suggested that, as devices are
    miniaturized, they lose their ferroelectric character. These studies
    showed that ferroelectricity persists in films only 6 atoms thick.
    This landmark success was achieved using a unique instrument to
    observe thin film growth with high intensity x-rays from the
    Advanced Photon Source. X-rays reveal in real time the film
    structure as it grows, atomic layer by atomic layer. The in-situ
    x-ray techniques developed for this study can now be used to
    understand the synthesis and environmental interactions of other
    complex materials, thus addressing a wide range of energy-related
    challenges.

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-   ***A Superconductor that Tolerates Magnetic Fields.*** One of the
    biggest obstacles to the practical use of superconductors is the
    motion of magnetic flux due to an electric current in a
    superconductor. This motion of magnetic flux reduced the
    superconducting properties. A large research effort has gone into
    finding ways to prevent energy loss occurring from the movement of
    magnetic flux in copper oxide high temperature superconductors. It
    has been found that the magnetic flux in certain magnesium diboride
    films is intrinsically motionless, or "frozen," in applied magnetic
    fields up to 14 Tesla. Such a complete apathy to an applied magnetic
    field has never been seen before in any other superconductor. While
    the theoretical explanation for this behavior has eluded scientists,
    the experimental finding has drawn a lot of attention. This behavior
    may make it possible to fabricate superconducting wire that can
    carry very large electric currents.

-   ***Using Electron Spin, not Electron Charge, to Carry
    Information.*** Today's computers are based on resistive circuitry
    using the movement of charged electrons. The resistance generates
    heat, and the removal of this heat is a fundamental limiting factor
    in creating the next generation of ultra small and ultra fast
    circuit elements. In a remarkable discovery, theorists have
    determined that in certain materials a spin current can be created
    with the application of a suitably oriented electric field, with no
    dissipation of energy. The spin current could potentially be used to
    carry out the same logic operations with no energy loss. This has
    been verified recently with experiments on gallium arsenide. This
    discovery may lead to computers with much greater capabilities
    including speed and capacity due to smaller circuit elements and
    with a significant reduction in energy loss.

-   ***Plutonium Helps Understand Superconductivity's Mysteries.***
    Magnetic resonance studies of the fundamental mechanism responsible
    for superconductivity in PuCoGa~5~ reveal strong similarities to the
    high-T~c~ copper oxide materials. These results confirm earlier
    theories that this unique family of plutonium superconductors is
    nearly magnetic. This is a new class of superconducting materials
    and forms a conceptual bridge between two families of magnetically
    mediated superconductors, the heavy fermion metals and the copper
    oxides. The discovery of additional classes of superconducting
    materials enhances our ability to understand the mechanisms
    responsible for high temperature superconductivity.

-   ***Ultrafast Studies of Nanocrystals.*** The fastest phase
    transition between nanocrystal structures ever recorded has been
    observed by ultrafast laser techniques. The reversible structural
    change in nanocrystals of vanadium dioxide switches the material
    from a semiconductor to a metallic phase, increasing the electrical
    conductivity by a factor of 100-10,000 depending on nanoparticle
    size. Correspondingly large changes from optical transparency to
    high reflectivity occur at the same time. Lasers with pulses as
    short as one ten-trillionth of a second were used to track the phase
    change in vanadium dioxide nanoparticles. This discovery may be key
    to possible applications requiring extremely rapid switching from
    transparent to reflective states. These include protective
    overlayers for sensitive infrared detectors, nonlinear optical
    switches, fiber-optic pressure sensors, and electrically or
    optically triggered transistors that could switch hundreds of times
    faster than conventional silicon devices.

-   ***First Direct Observations of Quasiparticles.*** Quasiparticles
    provide a convenient simplification to describe the behavior of
    electrons in a superconductor. A quasiparticle can be thought of as
    a single particle moving through a system, surrounded by a cloud of
    other particles either pushed away or dragged along by its motion.
    Prior investigations of their dynamics have been indirect. Through
    the use of a new optical technique it was possible to perform the
    first direct study of the dynamics of quasiparticles in a
    superconductor. It was discovered that the quasiparticles can
    propagate remarkably far, several hundreds of nanometers. Knowledge
    of the dynamics of quasiparticles, specifically their rates of
    diffusion, scattering, trapping, and recombination, is critical for
    the both the applications and fundamental understanding of
    superconductivity.

-   ***Confining Electrons in New Two-dimensional Materials.***
    Transition metal oxides, like semiconductors, are materials that
    confine electrons to a plane. It may now be possible to construct
    near-perfect layered materials of two perovskite structured
    materials. It has been shown through computational models that a
    single layer of LaTiO~3~ in SrTiO~3~ will serve as an electron donor
    and positive charge layer to retain those electrons in a thin layer
    as a two-dimensional electron gas (2DEG). Electrons behaving like a
    2DEG appear to be an exotic phenomenon, but they are not. Many
    semiconductor electronic devices operate by creating just such a gas
    by an applied electric field inducing a thin conducting region at an
    interface---the field effect transistor being the prime example.
    Such thin electron layers have become a valuable tool for scientists
    studying the ways in which electrons organize their collective
    behavior. By expanding the materials available to create 2DEGs, new,
    more diverse opportunities have been created to expand our knowledge
    of electronic behavior that in turn can produce new applications.

-   ***Inexpensive Route to Solar Cells Using Nanomaterials.*** New and
    novel semiconductor nanocrystal-polymer solar cells with
    surprisingly high efficiencies have been fabricated. In a solar
    cell, the conversion of light energy to electrical current occurs at
    the nanometer scale. Thus the development of methods for controlling
    materials on this scale creates new opportunities for more advanced
    solar cells. These advances are required because, although solar
    cells based on silicon and gallium arsenide have achieved high
    efficiencies and have found a variety of markets, more widespread
    applications remain limited by their high cost of production. These
    new cells are formed in an inherently inexpensive process from a
    colloidal solution of semiconductor nanocrystals in a semiconducting
    polymer. The unique features of nanosized objects are exploited to
    optimize the cell performance by controlling the shape of the
    nanocrystals. The performance of the new cells already rivals that
    of the best polymer-based devices. While the power conversion
    efficiency is still below that of current amorphous silicon and
    single crystal devices, there are opportunities to increase
    performance further by adding additional nanocrystal components to
    capture more of the solar spectrum. Furthermore, the same methods
    can be extended to address other optoelectronic applications, such
    as photodetectors and light emitting diodes.

-   ***Predicting Magnetism in Nanomaterials.*** As recording media and
    sensors become smaller and ever-denser, it is increasingly important
    to control magnetism in nanostructures. But the physical properties
    of magnetic nanostructures are linked in complex ways and are
    difficult to predict, much less control. In this work, the magnetic
    properties of a cobalt nano-wire next to a platinum surface step
    were predicted from first-principles. The results are in perfect
    agreement with experiment and show the importance of a proper
    quantum mechanical description of the interplay of different
    magnetic phenomena. This work, based on newly developed quantum
    mechanical models implemented on high-performance computers, shows
    that accurate predictions can be made for a nanostructure comprised
    of a few hundred atoms. With continued theoretical development and
    more powerful computers, this paves the way toward prediction and
    control of more complex and useful magnetic structures.

-   ***Explaining Materials Deformation Mechanisms from Atomic-scale
    Measurements.*** Using the world\'s most advanced electron
    microscope, the first direct observations of atomic details in
    complex crystalline dislocation cores revealed the atomic mechanisms
    underlying the deformation of intermetallic compounds with complex
    crystal structures. It was discovered that the diffusion of chromium
    atoms into and out of the crystal dislocation cores hinders
    dislocation motion in Laves-phase Cr~2~Hf, a model intermetallic
    compound, thus providing a clue as to the origin of the brittleness
    and poor low temperature ductility of these intermetallic alloys.
    The poor low-temperature ductility of these intermetallic alloys has
    prevented their fabrication and use for decades. Some of the most
    attractive high-strength alloys for advanced high-temperature
    fission and fossil energy conversion applications possess similar
    complicated atomic configurations and lack the low-temperature
    ductility required for their fabricated by conventional cold
    deformation processes without crack formation. This discovery
    provides new atomistic insight into the behavior of crystal
    dislocations in complex intermetallic compounds necessary to design
    new fabricable alloys with the required strength at high service
    temperatures.

-   ***Discovery of Mechanism of Surface Mass Transport.*** Researchers
    have discovered that trace concentrations of sulfur can enhance the
    rate of mass transport on copper surfaces by many orders of
    magnitude and have established the atomic scale mechanism by which
    this enhancement occurs. This discovery was enabled by low-energy
    electron microscopy measurements of the motion of singe-atom-high
    steps on copper exposed to calibrated doses of sulfur. By comparing
    observations of the motion of these steps with theoretical
    predictions based on calculations of the electronic structure of the
    surface, this research established that surface mass transport is
    catalyzed by the formation of a large number of mobile copper
    sulfide clusters. Such highly mobile clusters are believed to be a
    common feature of impure surfaces. The enhanced mass transport
    allows the formation of much flatter and more defect free surfaces.
    This discovery provides insight to many previous puzzling
    observations of anomalous surface mass transport. It is an important
    advance towards the capability to control the nanoscale morphology
    of surfaces, a critical necessity for nanoscale applications.

-   ***Superior Iron-based Alloys and Steels.*** Fundamental laws of
    alloying coupled with advanced microanalytical characterization led
    to the discovery that yttrium containing iron-based alloys
    substantially enhance the stability of the amorphous
    (non-crystalline) state. Two technical implications are: (1) large
    bulk physical dimensions of this class of amorphous alloys can be
    made and (2) this understanding provides a new direction for
    designing bulk amorphous metals for structural and functional
    applications. Bulk tool steel was fabricated that was twice as hard
    as conventional tool steel. These achievements are milestones in the
    science of amorphous metals and the design of functional complex
    metallic alloys. Even more important, this research has demonstrated
    that microalloying is a new approach for designing bulk amorphous
    alloys. Their unique atomic configurations and the absence of a
    crystalline lattice allow bulk amorphous metals to outperform their
    crystalline counterparts by exhibiting superior magnetic and
    mechanical properties and corrosion resistance coupled with high
    thermal stability.

-   ***Fracture Resistance Mechanism in Ceramics.*** Structural ceramics
    are complex structures of micron-sized matrix grains separated by a
    nanoscale intergranular film. For many years it has been observed
    that certain additives, specifically rare-earth atoms, influence the
    ceramic's fracture resistance. But detailed information about how
    this effect is achieved and how it can be controlled had been
    inaccessible with current diagnostic capabilities. Now, new scanning
    transmission electron microscopy (STEM) and associated chemical
    analysis techniques have revealed the local atomic structure and
    bonding characteristics of the grain boundaries with close to atomic
    resolution. Applied to silicon nitride ceramics containing a range
    of rare-earth additives, these methods together have revealed how
    each atom bonds at a specific location depending on atom radius,
    electronic configuration and the presence of oxygen; this variation
    in bonding sites can be directly related to the fracture resistance
    or toughness of the ceramic.

-   ***Better Protective Coatings.*** Previously unattainable insight
    into stress development and failure mechanisms in thermally grown
    surface oxides on metal alloys has been obtained by a new in-situ
    synchrotron x-ray technique. This technique enabled, for the first
    time, the uncoupling and isolation of mechanical stress
    contributions from oxide growth, phase transformations, and creep
    deformation processes. For pure thermally-grown alumina, steady
    state oxidation creates compressive stresses. However, when certain
    "reactive elements" are added to the alloy, it is found that tensile
    stresses develop instead. Maximizing the tensile offset can lead to
    dramatic improvement in performance of a protective oxide. A 10
    percent shift in the tensile direction can translate to a 40 percent
    improvement in operating lifetime. Better control of early stage
    oxidation leads to thinner, and thus longer lifetime protective
    oxides by speeding the transformation to a stable oxide structure.
    These results underpin future alloy development for high-temperature
    nuclear and fossil energy generation technologies and more fuel
    efficient jet engine applications where operating lifetime has great
    economic value.

-   ***New Composite Materials that Respond to Magnetic Fields.***
    Magnetic-field-structured composites are a novel class of material
    in which magnetic particles, dispersed in a polymerizable medium,
    are organized into chains and other structures by magnetic fields
    while the polymer solidifies. These chains of particles can be
    electrically conductive, and this electrical conductivity can be
    extremely sensitive to temperature, pressure, and chemical vapors
    that penetrate and swell the polymer. In the present work it was
    demonstrated that even modest magnetic fields produced by simple
    copper coils cause these materials to contract significantly, like
    artificial muscles. This contraction was found to be accompanied by
    an enormous, 50,000-fold increase in electrical conductivity. This
    is by far the largest "magnetoresistance" effect ever observed in
    such modest magnetic fields and paves the way to using magnetic
    fields to control heat and current transport in micro and nano
    machines, and to tailoring the sensing response of these materials.

-   ***The "Giant Proximity Effect."*** The reproducible confirmation of
    the existence of a Giant Proximity Effect (GPE) has challenged
    experimentalists for over a decade. In the traditional Proximity
    Effect (PE), a very thin layer of normal metal, when placed between
    two thicker superconductor slices, behaves like a superconductor.
    That is, superconducting or paired electrons retain phase coherence
    even while separated by the normal metal gap. In the newly
    discovered GPE, the normal-metal barrier layer is as much as 100
    times thicker than in the PE case, a result that stands outside of
    any present theories. In addition to challenging the theoretical
    community and providing new clues to the causes of high-temperature
    superconductivity, this result may lead to new advances in
    superconducting circuitry as it is relatively easy to prepare
    reproducible thick barriers which will improve device uniformity and
    yield.

-   ***World's Smallest Nanomotor.*** The smallest synthetic motor---a
    300 nanometer gold rotor on a carbon nanotube shaft---has been
    demonstrated. This "nanomotor" continues the dramatic advances in
    the miniaturization of electromechanical devices and is a key step
    in the realization of practical synthetic nanometer-scale
    electromechanical systems (NEMS). In initial testing, the rotor
    rotated on its nanotube shaft for thousands of cycles with no
    apparent wear or degradation in performance. This is attributed to
    the unique low-friction characteristics of the carbon nanotube
    shaft. The new motor design has significant potential for NEMS
    applications. It should be possible to fabricate arrays of
    orientationally-ordered nanotube-based actuators on substrates by
    using alignment techniques.

-   ***Magnetohydrodynamic Turbulence in Liquid Metals.*** Application
    of a strong magnetic field can completely change flow
    characteristics of an electrically conducting fluid. The
    transformation may occur in processes ranging from the generation of
    sunspots to crystal growth. One particular aspect of this
    phenomenon, the damping of flow variations along the magnetic field
    lines and the corresponding development of elongated or even
    two-dimensional flow structures, affect nearly all aspects of
    turbulent flow behavior, including heat transfer and mixing. In a
    series of high resolution numerical experiments it has been shown
    that the anisotropy of flow (or directionality of flow) patterns is
    a robust universal feature determined primarily by the strength of
    the magnetic field, conductivity, and kinetic energy. Furthermore,
    the elongation of flow patterns is approximately the same for flow
    structures of different size. This property can be effectively
    employed for accurate modeling of magnetohydrodynamic turbulence.
    The results of the work are relevant to technological applications,
    such as continuous casting of steel, crystal growth, and development
    of lithium breeding blankets for fusion reactors.

-   ***Nanoparticle Catalysts.*** Methods were developed for depositing
    and stabilizing nanometer-sized platinum group metals, including
    palladium and rhodium, on surfaces of carbon nanotubes in
    supercritical fluid carbon dioxide. Uniformly distributed
    monometallic and bimetallic nanoparticles with narrow size
    distributions are formed on the surfaces of the carbon nanotubes.
    The carbon nanotube-supported palladium and rhodium nanoparticles
    demonstrated improved performance over commercial carbon-based
    palladium and rhodium catalysts for hydrogenation of olefins and
    aromatic compounds. These new nanoscale catalysts are currently
    being tested as electrocatalysts for low temperature polymer
    electrode fuel cells applications.

    **Chemical Sciences, Geosciences, and Energy Biosciences
    Subprogram**

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-   ***Timing the World's Shortest X-Ray Pulses.*** Light sources based
    on particle accelerators, such as the Linac Coherent Light Source
    (LCLS), will revolutionize x-ray science due to their unprecedented
    brightness and extremely short pulse duration. To take full
    advantage of x-ray pulses that last only a few femtoseconds (10^-15^
    seconds), they must be timed relative to equally short pulses from
    an optical laser. Such measurements are vital to a wide range of
    LCLS experiments in which a sample is excited by an optical pulse
    and probed by an x-ray pulse. At the Stanford Linear Accelerator
    Center, ultrashort x-ray pulses were generated when 80-femtosecond
    electron pulses from an accelerator were sent through an undulator
    magnet; the x-ray and electron pulses were perfectly coincident in
    time. A crystal placed near the path of the electron beam
    experienced intense electric fields that altered the optical
    properties of the crystal, the electro-optic (EO) effect. An optical
    laser beam passing through the crystal sensed the EO effect, turning
    the time delay between the optical pulse and the electron/x-ray
    pulse into a spatial displacement on a detector. The current timing
    resolution of 60 femtoseconds could be improved to 5 femtoseconds,
    matching the projected performance of accelerator-based light
    sources into the foreseeable future.

-   ***Molecular Fragmentation Observed in Unprecedented Detail.***
    Researchers working at the Advanced Light Source have advanced our
    ability to observe the total destruction of a molecule to new levels
    of sophistication, challenging theoretical understanding and paving
    the way for research to be performed at next-generation light
    sources. When a hydrogen molecule is exposed to x-ray photons of the
    appropriate energy, the two electrons it possesses can be ejected at
    once, leaving behind two positively charged nuclei that rapidly
    explode. Thus, absorption of one x-ray photon causes the complete
    destruction of the molecule. Using modern techniques of
    three-dimensional imaging and ultrafast timing, the motions of all
    four particles from a single event can be related to one another.
    The results are surprising and challenge our current theoretical
    understanding of how x-rays interact with matter.

-   ***Complete Ionization of Clusters in Intense VUV Laser Fields.***
    BES-supported researchers have developed a theory that explains
    recently-observed ionization behavior of xenon clusters that were
    exposed to intense, coherent vacuum ultraviolet (VUV) pulses from a
    free-electron laser (FEL). Surprisingly, at intensities that produce
    only single ionization of an isolated xenon atom, the clusters
    irradiated by the FEL showed massive ionization in which every atom
    in the cluster was highly ionized, producing ions with charge states
    up to +8. This implies that each xenon atom in the cluster absorbed
    about 30 VUV photons. The key difference between clusters and
    isolated atoms is that energetic electron-ion collisions occur
    within the clusters and modify the single-photon absorption cross
    section, thus allowing a large number of photons to be absorbed.
    This process is called "inverse bremsstrahlung" and, when
    incorporated into a simple linear absorption model, clearly
    reproduces the experimental observations. Theories such as this will
    be needed to understand the behavior of matter when it is exposed to
    intense, coherent X-ray pulses from next-generation light sources
    such as the LCLS.

-   ***The Roaming Atom: Straying from the Lowest-energy Reaction
    Pathway.*** A fundamental tenet of modern chemical reaction theory
    is the concept of the transition state, a transient molecular entity
    that lies on the most direct pathway from reactants to products and
    whose properties govern the rate of reaction. Recently, it was shown
    that in a simple chemical reaction, the decomposition of
    formaldehyde, a substantial fraction of the dissociating molecules
    avoid the region of the transition state entirely. These studies
    combine ion imaging experiments with theoretical trajectory
    calculations to reveal that the dissociation takes place via a
    mechanism in which one hydrogen atom begins to roam away from the
    molecule and nearly dissociates, then returns to react with the
    remaining hydrogen atom. Along with other recent findings on
    reactions such as O + CH~3~, these results challenge conventional
    notions of chemical reactions and raise the question of how common
    such processes might be. A key question is whether such a mechanism
    applies only to reactions forming hydrogen, during which a light
    hydrogen atom may rapidly explore regions far from the conventional
    transition state.

-   ***New Combustion Intermediates Discovered.*** A complete mechanism
    for the combustion of simple hydrocarbon fuels includes dozens of
    distinct molecular species and hundreds of chemical reactions. The
    identification of which molecules to include in a combustion
    chemistry mechanism still requires experimental detection,
    particularly for reactive intermediates. A class of unstable
    molecules known as enols, which have OH groups adjacent to
    carbon-carbon double bonds, are not currently included in standard
    combustion models. In work performed at the Advanced Light Source,
    significant quantities of 2, 3, and 4-carbon enols were observed
    using photoionization mass spectrometry of flames burning
    representative compounds from modern fuels. Concentration profiles
    of the enols taken in the model flames demonstrate that their
    presence cannot be accounted for by isomerization reactions that
    convert more stable molecules into enols. This leads to the
    conclusion that an entire class of important reaction intermediates
    is absent from current combustion models, and the models will need
    substantial revision.

-   ***Unified Molecular Picture of the Surfaces of Aqueous
    Solutions.*** A long-term controversy exists regarding the detailed,
    molecular nature of the surface of an aqueous solution containing
    molecular ions (or electrolytes). Joint theoretical and experimental
    studies have led to a new, unified view of the structure of the
    interface between air and aqueous electrolytes. Molecular dynamics
    simulations have shown that in basic salt solutions positively
    charged ions (cations) are repelled from the interface, while
    negatively charged ions (anions) exhibit a propensity to migrate
    toward the surface that correlates with the anion's polarizability
    and physical size. In acidic solution, however, there is a high
    propensity for cations to be located at the air/solution interface.
    In this case, both cations and anions are concentrated at the
    surface and reduce the surface tension of water. These conclusions
    have been verified by surface-selective nonlinear vibrational
    spectroscopy experiments. Understanding the behavior of ions at
    aqueous surfaces is important to the heterogeneous chemistry of
    seawater aerosols and to the tropospheric ozone destruction in the
    Arctic and Antarctic due to reactions on ice pack covered with sea
    spray.

-   ***Self-Assembled Artificial Photosynthesis.*** In natural
    photosynthesis, self-assembly of light-absorbing molecules, or
    chromophores, at specific distances and orientations is especially
    important in two parts of the overall photosynthetic system: the
    antenna component, where light is collected; and the reaction
    center, where charge is separated. Recently, a green organic
    chromophore was discovered that exhibits photophysical and
    photoredox properties similar to those of natural chlorophyll a.
    When conjoined with four similar chromophores, the molecules
    self-assemble in solution to form an antenna-reaction center
    complex. Self-organization of the large structure is believed due to
    the propensity of these similar chromophores to align in a cofacial
    stacking arrangement. The self-assembled organic has attributes that
    closely mimic the primary events in photosynthesis: efficient light
    energy capture over a wide spectral range, energy funneling toward a
    core electron-transferring unit, and excited-state symmetry breaking
    of a molecular pair resulting in charge separation. The structure of
    the new array was determined at the Advanced Photon Source.

-   ***Two-Dimensional Spectroscopy Reveals Energy Transport Pathways In
    Photosynthesis.*** Photosynthetic antennas capture solar photons and
    transport the absorbed energy to the photosynthetic reaction center
    where charge separation occurs. Energy transfer by the antenna is
    nearly 100 percent efficient, although the mechanism for the process
    has been elusive. A novel spectroscopic technique known as a
    two-dimensional photon echo, commonly used in the infrared, has been
    extended to the visible spectral region and has revealed important
    details about energy transfer in photosynthetic light harvesting. In
    antenna pigments from green sulfur bacteria, distinct energy
    transport pathways have been identified that depend on the spatial
    properties of the pigment-protein complex. Contrary to the accepted
    model of a sequential cascade in energy from high- to low-lying
    excited states, these results reveal excited states that are
    distributed over two or more chlorophyll molecules and a pathway in
    which energy levels are skipped on the way to the lowest level. The
    new two-dimensional electronic spectroscopic method, which measures
    electronic couplings and maps the flow of excitation energy, opens
    the door to investigation of other photoactive systems and can be
    applied to improving the efficiency of molecular solar cells.

-   ***How Water Networks Accommodate an Excess Electron.*** In bulk
    water an excess electron can become trapped within a cavity formed
    by a network of hydrogen-bonded water molecules. This "solvated
    electron" is a critical chemical intermediate in the radiolysis of
    aqueous solutions. One approach to understanding the solvated
    electron is to study the structure and dynamics of clusters of water
    containing an excess electron in the gas phase. This approach has
    not yet been successful because these anionic water clusters are
    hard to make and because an accurate theoretical description for
    them is lacking. Recent work has shown that anionic clusters
    containing four to six water molecules can be created within
    gas-phase matrices of inert argon clusters, where their infrared
    spectra can be obtained. Analysis of these spectra using density
    functional theory shows that the diffuse electron interacts most
    strongly with a single water molecule that is hydrogen bonded to two
    other waters in a rearranged network. The spectra also exhibit
    evidence for the rapid exchange of energy between the vibrations of
    the hydrogen atoms on the unique molecule and the excess electron.
    This new technique can now be extended to larger water clusters that
    better mimic the solvated electron in bulk water.

-   ***Gold, a Magnificent Nanoscale Catalyst.*** When gold atoms are
    assembled as tiny clusters smaller than 8 nanometers and attached to
    the surface of titanium oxide, they acquire the remarkable ability
    to dissociate oxygen at room temperature and insert that oxygen into
    very specific locations in molecules. The origin of such unusual
    reactivity---discovered some 10 years ago---has until recently
    evaded a widely accepted explanation. Numerous parameters in the
    material are important and usually cross-correlated: gold particle
    dimension and shape, metal oxidation state, oxide support
    reducibility, and interaction of the gold with the support.
    Separating those parameters in these materials, which are
    macroscopically amorphous, would demand special analytical
    techniques that are able to focus on the detailed properties of
    individual chemical bonds in the solid. Therefore, researchers
    pursued a different route using existing and well-known surface
    science techniques: they accurately synthesized and stacked
    one-atom-thick layers of gold extended in two dimensions, and
    supported them on top of perfect oxide crystals of known structure.
    They demonstrated that the nanoscale properties of gold metal are
    achievable by controlling the layer thickness to between 2 and 3
    atoms. Such knowledge can now be extended to the manipulation of
    selective oxidation chemistry or the discovery and assembly of new
    catalysts.

-   ***Theory Guides Scientists on How to Extract Hydrogen from Natural
    Sources and Store it Efficiently.*** Two of the keys to a hydrogen
    economy are having an abundant supply of hydrogen and having
    materials that can store such hydrogen in a readily accessible form.
    Both of those challenges can be addressed by designing
    materials---chemical catalysts---that bind atomic hydrogen with
    medium strength and release molecular or gaseous hydrogen with very
    little heating. A random or systematic search for such catalysts,
    even with high-throughput techniques, would be very expensive and
    take many years. Scientists resorted to so-called density-functional
    theory, which is an electronic structure theory of matter, and other
    theories that describe chemical reactivity to design the ideal
    bimetallic catalysts, combinations of two metals, in special atomic
    arrangements that would result in solids with the desired
    properties. They arrived at a new theoretical construct called
    near-surface alloys of metals, such as a crystal of platinum
    containing a single layer of nickel atoms in its second row, that
    possesses the unique catalytic behavior sought. Having by now mapped
    entire families of such new theoretical materials---a feat
    unachievable by direct experimental means---these scientists have
    embarked on the challenge of fabricating these new structures and
    have already demonstrated their concept with a few successful
    examples.

-   ***Devising the Next-Generation Wonder Molecules---Fine Chemistry
    inside Nano Cages.*** In the future drugs, fibers, fuel additives,
    molecular electronics devices, solar energy conversion dyes, and
    flavors may be synthesized in a similar manner using sets of
    discrete cavities to contain and isolate single molecules or just
    reacting pairs of molecules and catalysts. The "single-molecule
    catalysis" concept would allow maximum control of the environment
    surrounding a molecule, the spatial arrangement adopted by its
    atoms, the type of bonds made available for reaction, and even how
    the energy is coupled to and transferred to the molecule. Such level
    of control would result in the ability to break bonds or insert or
    remove atoms or change the spatial arrangement of atoms in very
    specific ways and not others. The resulting products would possess
    properties---chemical, biological, optical, electronic, or
    mechanical---superior to those achievable through less controllable
    chemistry. Researchers are beginning to show that this goal may be
    achievable. So-called supramolecular or larger-than-molecules cages
    made with organometallic compounds were used to host other
    organometallic complexes that have catalytic properties, such as the
    ability to specifically break carbon-hydrogen bonds. They have shown
    that certain carbon-hydrogen bonds are selectively broken and that
    only certain members of a chemical family undergo reaction, and not
    others. They have even shown that the constrained environment also
    leads to enhanced rate of production of the most desired product,
    which is in itself a revolutionary discovery.

-   ***Controlling the Crash-landing of Biomolecules on Surfaces.***
    Researchers have, for the first time, demonstrated that peptide ions
    retain at least one proton after soft landing on chemically
    modified, "fluffy" surfaces. Controlled deposition on surfaces holds
    great potential for applications such as selective chemical
    separations and analysis. Soft landing refers to the intact capture
    of large size-selected, charged molecules on surfaces of liquids or
    solids. Previous research suggests that soft landing provides a
    means for highly specific deposition of molecules of any size and
    complexity on surfaces using only a tiny fraction of material
    normally used in standard synthetic approaches. In the present
    studies, peptide ions are attractive as model systems that can
    provide important insights on the behavior of soft-landed
    macromolecules. The researchers used a specially designed mass
    spectrometer configured for studying interactions of large ions with
    surfaces. The special characteristics of the instrument enabled
    quantitative investigation of the effect of the speed and mass of
    ions on the soft landing process. For example, it was determined
    that even collisions with high energies can result in deposition of
    intact ions on surfaces.

-   ***Removal of Radium Ions from Water using Special "Grabber"
    Molecules.*** Researchers demonstrated a process that is highly
    selective for binding radium cations. It is a significant challenge
    to remove radioactive radium cations from wastewater since the large
    excess of other non-radioactive ions in solution can interfere with
    the selective extraction of radium. In the new work, a specially
    designed molecule was used to selectively bind radium. This
    supramolecular assembly made from isoguanosine is just the right
    size to extract radium in the presence of other cations such as
    magnesium and sodium.

-   ***How Molecules Move through Small Holes.*** Measurements of
    transport through 15-nanometer pores have been compared to
    theoretical results to yield new understanding of differential
    transport at small scales. This knowledge is important for an
    understanding of separation processes at the molecular level, and
    could lead to a new generation of analytical devices based on
    microfluidic platforms. By adjusting physical parameters such as the
    channel diameter, and applying the appropriate external electrical
    potential, arrays of nanochannels---formed by nanocapillary array
    membranes---can be made to behave like digital fluidic switches, and
    the movement of molecules from one side of the array to the other
    side can be controlled. Combining model calculations with
    experimental characterization provides important insights into the
    mechanism of molecular transport and, additionally, provides
    quantitative measures of the surface characteristics of the interior
    of the pores.

-   ***Using Thorium and Uranium to Activate the Carbon-Hydrogen and
    Carbon-Nitrogen Bonds in Molecules.*** The extent of
    electron-sharing in bonds with metals is an important property in
    catalysis. The correlation of bond covalency with reactivity can be
    elucidated by determining the reactivity of actinide (thorium,
    uranium, and other elements in the same row of the periodic table)
    ions with multiply bonded functional groups. Pyridine N-oxide
    (C~5~H~5~N-O), which has a relatively stable benzene-like ring, can
    transfer oxygen atoms to certain transition metals. Chemists have
    discovered that some uranium and thorium compounds can make C-H
    bonds in pyridine N-oxide more reactive by forming metal-carbon
    bonds. The structures of the products produced in these new
    reactions have been confirmed by x-ray crystallography. These
    reactions provide examples of C-H and C=N bond activation that is
    mediated by actinide metals. These studies may offer insights into
    catalytic removal of nitrogen-containing compounds from petroleum
    feedstocks, which is necessary to reduce nitrogen oxide emission in
    fuels.

-   ***Elusive Carbon Dioxide Binding Mode Discovered in New Uranium
    Complex.*** Carbon dioxide (CO~2~) is a stable molecule with two
    strong carbon-oxygen bonds. Inorganic chemists seek to mimic the
    catalytic chemical processes by which carbon dioxide is modified by
    plants to form sugars. This process can remove CO~2~ from the
    atmosphere and minimize atmospheric release of CO~2~ in industrial
    processes such as refinement of hydrocarbons. A new
    exquisitely-designed uranium complex has been found to react with
    CO~2~ such that one electron is transferred from the U^3+^ center to
    CO~2~, producing a species with an unusual linear CO~2~ that binds
    to uranium and has one weaker oxygen-carbon bond. Uranium is an
    essential component of this species because the U^3+^ ion is large,
    electron-rich, and has the right structure to participate in
    bonding. This species is unique in that the CO~2~ remains linear,
    with one C-O bond longer and weaker than the other. The molecular
    structure, bond lengths and oxidation state were established
    experimentally. The linear M-O-C-O coordination had previously been
    seen only in an iron enzyme. The new uranium-CO~2~ complex
    represents a chemical image of a catalytic process and may make it
    possible to design new catalysts to reduce the concentration of
    CO~2~ in the atmosphere.

-   ***Plutonium is Caged and Illuminated by Synchrotron Light.*** A new
    complexant, which was synthesized to extract plutonium and other
    actinide elements selectively, has shown promise to remove plutonium
    from mammals. Microscopic crystals (about the thickness of a human
    hair) of a plutonium complex have been produced to provide a
    structural model in order to design new actinide-selective binders.
    Using the Advanced Light Source, researchers determined the detailed
    structure of these crystals and showed that individual plutonium
    ions are trapped in cavities produced by eight oxygen atoms from the
    binder molecules. This structural determination will serve as a
    model of such complexes on which to base the design of novel
    molecules that are cages for toxic metals.

-   ***Sheer Energy: Thinner, Cheaper Fuel Cell Catalysts.*** Fuel cells
    are a major source of clean energy in the hydrogen economy. Their
    economic development critically depends on cheaper electrocatalysts
    for oxygen reduction. The slow nature of this reaction causes a
    major limit in fuel cell efficiency. High precious metal content is
    another drawback of existing technology. Researchers coated five
    cheaper metals with a layer of platinum one atom thick and tested
    them. For most of the platinum \"monolayers,\" the reaction occurred
    more slowly than it does on the thicker platinum layer currently
    used in fuel cells. But adding a monolayer of platinum to the
    cheaper metal palladium sped up the reaction. Theoretical
    computations predicted how the platinum monolayers are affected by
    atoms from the underlying layer of metal. The theory agreed well
    with the experiments and showed that a platinum monolayer on
    palladium balances two competing needs: it is reactive enough to
    break the bonds between oxygen atoms yet does not cling to the
    oxygen atoms so tightly that it prevents them from reacting with
    hydrogen. This method can dramatically decrease the expensive metal
    loading in fuel cells and improve cost and performance.

-   ***Advances in Computational Chemistry Research.*** Basic research
    in computational chemistry has resulted in a superior method for the
    prediction of chemical behavior from computational quantum mechanics
    and statistical mechanics. The method is based on treating the
    solvent in which a molecule is placed as a continuum, and
    determining the cavity-formation energy from statistical mechanics,
    and the electric contributions from quantum mechanics. This work has
    now been published and a leading chemical process simulation company
    has incorporated this method into the most recent release of their
    industry dominating process simulator. This work will impact modern
    industrial plant and process design and lead to higher energy
    efficiencies through effective modeling of manufacturing processes.

-   ***Is CO~2~ Gone When You Put It In The Ground?*** There are only
    two options for dealing with increasing CO~2~ concentrations in the
    atmosphere---get rid of new CO~2~ actively or discontinue producing
    it and wait for natural processes to remove the excess over a very
    long time. Both approaches will likely be needed in the future.
    Researchers have been developing capabilities for realistic modeling
    of CO~2~ injection into deep geological formations and for
    understanding dynamic processes associated with the injection in
    order to provide a scientific basis for evaluating the injections
    feasibility. Computational models were developed for coupling fluid
    properties, chemical and thermodynamic data, and rock-fluid
    interaction measurements. Reservoir dynamics were investigated on
    different levels of complexity and scale for natural and engineered
    systems. These types of calculations also form the basis for
    understanding possible leaks which may be major regulatory and
    insurance concerns for large scale geological CO~2~ sequestration.
    The improved computational codes from this project were also used as
    the basis for design calculations for CO~2~ injection at the Frio
    Test Site as part of the Office of Fossil Energy funded Climate
    Change Technology Program.

-   ***Improving Our Vision of the Subsurface.*** Large scale subsurface
    seismic measurements, although adequate for simple oil and gas
    exploration or waste site characterization, are inadequate for high
    hydrocarbon recovery rates or more effective environmental
    remediation or monitoring. Research is providing a better
    understanding of geophysical measurements of compressional and shear
    wave velocities, elastic moduli, and seismic anisotropy as they vary
    as functions of porosity, permeability, fluid contents, and
    stresses. A fiber-optic "optical" strainmeter has been developed
    that provides spatially averaged properties over a centimeter or
    "core" length scale intermediate between point measurements and a
    meter-scale bulk-measurements. The increased accuracy and
    sensitivity in measuring elastic deformation during applied
    sinusoidal stress will enable better discrimination between strain
    (elastic wave transmission efficiency) and phase lags (attenuation
    indicative of fluid content and type). In addition, the highly
    precise optical strain gage measurements will allow higher
    resolution testing of the significance of different types of
    heterogeneity at the core scale, in order to enable prediction of
    these properties at larger scales. The fiber optic sensor has been
    demonstrated to have a significantly higher sensitivity than other
    strain gages.

-   ***The Auxin Receptor: A Holy Grail in Plant Science.*** The plant
    growth hormone called auxin is a small molecule, indole acetic acid
    (IAA)---too small to have the expected breadth of "informational"
    content to achieve its myriad effects of controlling the growth of
    leaves, stems, roots, flowers, fruits, and growth changes in
    response to light and gravity. Recent research demonstrated that IAA
    interacts directly with a much larger molecule, a protein, which was
    earlier shown to affect plant growth by stimulating the expression
    (activation) of certain growth-related genes. Now the solution to
    the mystery of auxin action is becoming clear. It turns out to be
    similar to an electric switch, but a bit more complex. We are
    beginning to unravel the molecular details of auxin's biological
    activity.

**Selected FY 2005 Facility Accomplishments**

-   **The Advanced Light Source (ALS)**

    *Beam-Size Stability Improved.* Over the last five years,
    elliptically polarizing undulators (EPUs) have been used very
    successfully at the ALS to generate high-intensity photon beams with
    variable photon polarization (from linear to circular). However,
    users were not completely satisfied with the EPUs performance
    because they degraded the beam quality by increasing the photon beam
    size. Based on detailed magnet measurements, a system was developed
    that maintains a constant beam size. It is now being employed in
    routine user operation solving a problem that has affected many
    other light sources*.*

    *New Undulator Beamline for High-Resolution Photoemission Electron
    Microscopy.* Beamline 11.0.1 is a new elliptically polarizing
    undulator (EPU) beamline dedicated to photoemission electron
    microscopy (PEEM) at the ALS. An EPU, the third installed at the
    ALS, delivers light into the new beamline, which began commissioning
    March 2005. With full polarization control and continuous coverage
    optimized over key energy regions, this beamline will be an
    attractive user facility for organic and magnetic
    polarization-contrast microscopy. This beamline will have an
    aberration-corrected photoemission electron microscope (PEEM-3) with
    a spatial resolution of approximately 5 nanometers.

    *New In-Vacuum Undulator Beamline for Femtosecond X-ray Studies*.
    Beamline 6.0.1 for soft x-ray science with ultrashort photon pulses
    of 200 femtoseconds was ready for commissioning in July 2005. The
    beamline is unique in the U.S. and will be made available to users
    in FY 2006. The primary components are a vacuum undulator to produce
    x-rays over a wide photon-energy range, optical components,
    including a spectrograph for recording an entire x-ray absorption
    spectrum from one photon pulse, and a high-repetition-rate
    femtosecond laser system.

-   **The Advanced Photon Source (APS)**

    *More Stable Beams.* Using a technique pioneered at the APS, 175
    girders supporting accelerator components in the APS storage ring
    have been displaced by as much as 6 mm during scheduled tri-annual
    maintenance periods over the last seven years, eliminating the stray
    radiation background signals. As a result, photon beam position
    monitors (BPMs) for insertion devices over the entire storage ring
    circumference are now operating on line. The APS leads the world in
    the use of photon BPMs for insertion device beamlines. Use of these
    monitors has improved long-term x-ray beam angular stability by more
    than a factor of five. Users are able to scan the x‑ray photon
    energy by changing the insertion device gap on demand, while still
    maintaining superior photon beam stability on their samples. The
    payoff is improved ability to resolve micron and nanometer-sized
    features in samples

    *Improved Timing Experiments.* The x-ray pulse structure at the APS
    is on the order of 100 picoseconds. This pulse width enables special
    classes of timing experiments where the physical phenomena require
    fast time resolution. Recent experiments at the APS using this
    technique have involved the study of porphyrins that may one day
    form the building blocks of novel catalysts, photonic devices, and
    efficient solar-power units. The APS has a special operating mode to
    facilitate these types of measurements. In this mode, a single x-ray
    timing pulse is isolated from the other x-ray pulses. The intensity
    in the pulse is determined by the amount of charge stored in the
    isolated electron bunch that generates the photon pulse. Recent
    changes to the storage ring top-up injection method, which allows
    the APS linear accelerator to vary the injection charge along with
    increasing the injection frequency from two minutes to one minute,
    have resulted in doubling the single pulse-intensity without
    adversely affecting the non-timing experiments.

    *Improved Mirrors for X-ray Focusing.* Elliptically-shaped mirrors
    based on new technology developed at the Advanced Photon Source are
    being used to achieve unprecedented focusing of high-brightness
    x-ray beams. These mirrors are especially useful for producing the
    microbeams that are used to probe the composition and structure of
    materials. They are being applied to studies such as microstructural
    analyses of structural changes arising from welding operations and
    detailed investigations of the three-dimensional structure of
    complex crystalline samples*.*

    *Nanoprobe Beamline Commissioned for First Experiments.* The world's
    first hard x-ray nanoprobe was activated in March 2005, at the APS.
    The Nanoprobe beamline is a central component of the new Center for
    Nanoscale Materials at Argonne National Laboratory. The x-ray
    nanoprobe will have a spatial resolution of 30 nanometers or better,
    the highest of any hard x-ray microscopy beamline in the world. It
    will offer fluorescence, diffraction, and transmission imaging in
    the x-ray spectral range of 3-30 keV, making it a valuable tool for
    studying nanomaterials.

-   **The National Synchrotron Light Source (NSLS)**

    *New X-ray Micro-Diffraction Instrument.* This instrument to be used
    for nanoscale research was developed at the X13B beamline to take
    advantage of the small source size of the in-vacuum mini-gap
    undulator in the X13 straight section of the NSLS x-ray ring. It
    consists of five main subsystems: monochromator, focusing optics,
    sample manipulator, charge-coupled detector (CCD) area detector, and
    a point detector with two degrees of freedom. The sample stages are
    equipped with integrated submicron position encoders for excellent
    positional precision and repeatability. The point detector assembly
    allows the use of analyzer crystals to obtain better resolution. A
    key design feature is the close attention paid to mechanical
    coupling of the focusing optics to the sample positioner to reduce
    vibrations and improve the microscope stability for the users.

    *Elliptically-Polarized Wiggler Beamline Upgrade.* The
    Elliptically-Polarized Wiggler (EPW) located in the X13 straight
    section of the NSLS x-ray is a unique radiation source that produces
    time-varying elliptically-polarized x-rays for magnetism studies. A
    major upgrade was performed on beamline X13A to enhance its
    performance. It included replacement of the existing horizontal
    focusing mirror, which had been plagued by poor reflectivity as well
    as mechanical and thermal stability problems, with a new
    water-cooled spherical mirror. The new mirror system increases the
    horizontal photon collecting angle by a factor of two and is fully
    motorized to allow precise manipulation and optimization of the
    mirror's position. In addition, the beamline interlock and control
    systems were upgraded. The beamline upgrade has resulted in an order
    of magnitude increase in the photon intensity delivered to the
    sample, and the elimination of mechanical and thermal instabilities.
    These improvements have led to more efficient use of the beamline
    and increased magnetic sensitivity in the measurements.

    *Development of a Photon-Counting Silicon Microstrip Array
    Detector*. The NSLS detector group has developed an extremely
    versatile 1-dimensional position sensitive detector. It is based on
    custom microelectronics developed at Brookhaven National Laboratory,
    and consists of a linear array of silicon photodiodes, each 0.125 x
    4 mm, which is connected to a set of 32-channel custom integrated
    circuits and a microprocessor system. The detector system's
    performance is several orders of magnitude better than one can
    achieve with charge-coupled type detectors. It is easily adaptable
    to as large an array as is needed by the application. For example,
    arrays of 320 and 640 strips, 40 and 80mm long have been fabricated
    for real-time x-ray scattering.

    *X-ray Ring Lattice Symmetry Restored.* The most direct benefit for
    the NSLS user community was the restoration of the x-ray ring
    magnetic field lattice symmetry, which for many beamlines resulted
    in a 25 percent reduction of the horizontal beam size and an
    increase in photon intensity delivered to a sample. The desired
    eight fold symmetry of the x-ray ring magnet lattice can be lost
    from errors in the x-ray ring quadrupole field strengths. The
    quadrupole errors can be partially compensated by trim coils
    available in the x-ray ring for one of the quadrupole magnet
    families. These errors were determined from an elaborate analysis of
    the electron orbit measurements taken as quadrupole magnet field
    strengths were systematically varied. This improvement allowed the
    NSLS to restore the eight fold symmetric x-ray ring magnet settings
    for routine operations.

-   **The Stanford Synchrotron Radiation Laboratory (SSRL)**

    *First SPEAR3 Run Completed.* In the commissioning run for the new
    SPEAR3 accelerator, the facility proved to be exceptionally
    reliable, providing very stable beam for a very high percent (97) of
    the scheduled time. This is higher than ever recorded with SPEAR2,
    and an exceptional achievement for a new storage ring. The user run
    commenced in March and the SPEAR3 storage ring operated at 3 GeV/100
    mA and provided 30+ hour life times. (The average uptime over the
    past five years was 96%.) During the run, users on 239 different
    proposals received beam time in a total of 466 experimental starts
    involving 1,516 researchers.

    *First High-Current SPEAR3 Tests Performed.* SSRL conducted three
    special 8-hour shifts of SPEAR3 operation with currents above the
    official safety envelope value of 100 mA. These high-current test
    shifts took place on swing shifts with the experimental floor
    cleared of non-radiation workers. The main purpose of these tests
    was to determine if multi-bunch electron beam instabilities will be
    encountered at higher current operation, in which case a program to
    implement a costly multi-bunch feedback system would have to be
    launched. Other potential problems, primarily excessive component
    heating, are also of concern. The current reached in these tests was
    limited to 225 mA by the power rating of some absorbers in a legacy
    insertion device chamber. This current was reached and a
    comprehensive search revealed no apparent beam instabilities.

    *New Methods Developed for Studying Structures of Nanomaterials.*
    The reactivity and properties of nanomaterials are highly influenced
    by particle size and atomic-scale structure. Researchers at SSRL
    have recently demonstrated that the combined use of several x-ray
    scattering and absorption measurement techniques leads to quantum
    leaps in understanding the structures of nanomaterials. X-ray
    scattering measurements allow experimenters to combine size and
    shape information with structural information to remove the
    small-particle size contribution to x-ray diffraction peak
    broadening, whereas x-ray absorption measurements provide
    complementary, metal-specific information on local atomic structure
    in disordered materials. Measurements on zinc sulfide have
    conclusively demonstrated that structural relaxation of surface
    atoms causes inhomogeneous internal strain, markedly altering its
    material properties. This multi-technique nano-characterization
    approach has further been advanced by developing methods for the
    routine characterization of bacterial nano-minerals under
    fully-hydrated in-situ conditions. Bacterial nanominerals are an
    important class of naturally occurring nanomaterials that help to
    control the composition of the atmosphere, the potability of natural
    waters, and the arability of soils. This multiple-technique method
    provides unique information of wide interest to the nanoscience
    community.

-   **The Intense Pulsed Neutron Source (IPNS)**

    *Simultaneous Measurement of Mixed-conductor Lattice Relaxation,
    Diffusion, and Gas Conversion.* The General Purpose Powder
    Diffractometer (GPPD) at the IPNS is equipped with a specially
    designed controlled-atmosphere furnace, where samples in pellet or
    hollow-tube form are exposed to mixtures of gases to control oxygen
    and hydrogen content from highly oxidizing to highly reducing
    environments. Using two separate gas delivery "circuits," simulated
    membrane operation conditions can be achieved whereby the responses
    of oxygen-permeable membranes to strong oxygen partial pressure
    gradients can be studied. Exhaust gases are analyzed with a Residual
    Gas Analyzer to probe for leakage and to quantify gas conversion
    reactions. Dense ceramic components with mixed-conduction properties
    and high oxygen permeability are important as membranes for oxygen
    separation and solid oxide fuel cell applications. Membranes are
    typically operated at elevated temperatures (800-1000°C) and exposed
    to large oxygen partial pressure gradients. This experiment
    reproduces the conditions under which these membranes will be used
    commercially and provides insights into the unusual differential
    oxygen partial pressure stability of these materials.

    *Accelerator Systems Improvements*. Efforts include: completion of
    the beamline-magnet power supply upgrades, replacing the originals
    with higher-efficiency and better regulated units; completion of a
    full year of operation of the first of two new kicker-magnet power
    supplies; and completion of full-power tests of the new third-rf
    system that will be installed in the synchrotron ring to provide new
    proton beam capture and handling capabilities.

    *National Neutron and X-ray Scattering School.* During August 2005,
    Argonne National Laboratory again hosted the National School on
    Neutron and X-Ray Scattering. The school continues to attract
    outstanding graduate students and post-doctoral appointees with 150
    applications for the 60 positions available in 2005. The intensive
    training introduces students to the theory of, and provides hands-on
    experimentation in, x-ray and neutron scattering.

-   **The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
    Neutron Science Center (LANSCE)**

    *Neutron Scattering Winter Schools.* The First and Second Annual
    LANSCE Neutron Scattering Winter Schools were held, with 30 students
    from a wide geographical distribution attending each School. The
    2004 topic was magnetism and the 2005 topic was mechanical
    properties of materials. During nine intensive days in Los Alamos,
    students had lectures from world experts on the key materials issues
    for the School theme, modeling and theory, and neutron scattering
    techniques addressing these issues. In addition, the students had
    the opportunity to gain hands-on experience in neutron-scattering
    techniques and data analysis.

    *New Sample Environments.* A major emphasis on sample environments
    in FY 2005 has greatly enhanced the low temperature, high field, and
    high pressure possibilities for user experiments. Investments in new
    low temperature sample environments, high pressure instrumentation,
    sample goniometers, and support staff have made users more
    productive. Along with the 11-Tesla superconducting magnet
    commissioned in 2004, the Lujan Center's suite of sample
    environments for condensed matter physics has dramatically improved
    in FY 2005. A rheometer designed to synchronize with the 20 Hz Lujan
    Center pulsed neutron beam is expected to be tested in FY 2005. It
    will provide a unique capability to impose accurate hydrodynamic
    shear on polymer solutions and colloidal suspensions while
    performing structural measurements by small-angle neutron
    scattering.

    *Instruments Enhancement.* The High Intensity Powder Diffractometer
    (HIPD) and the Single Crystal Diffractometer (SCD) have received
    upgrades to software, shielding, alignments, and hardware that have
    increased their neutron intensity, user throughput, and efficiency.
    New hardware and software controls on the Low-Q Diffractometer (LQD)
    and a new detector have made small angle neutron scattering (SANS)
    more effective.

-   **The High Flux Isotope Reactor (HFIR)**

    *Common Guide Casings for Seven New Instruments Installed.* Neutron
    guides transport cold neutrons (energies \~0.1--20 meV) with little
    loss in flux. This permits one to transport neutron beams from the
    source to instruments several tens of meters away. This lowers the
    instrumental background noise from gamma rays and unwanted neutrons
    since one can place the instruments far from the source. Also, the
    guides have a slight curvature which removes the "line-of-sight"
    view of the neutron source and further reduces this background. The
    guides are made by coating glass with layered coatings called
    supermirrors which are highly reflective for neutrons. These flat,
    coated glass plates are then assembled to form hollow rectangular
    cross-sectioned pipes with the coated sides forming the interior
    walls of the pipes. These guides will be illuminated with neutrons
    produced by the new HFIR cold source to be installed early in 2006.

    *HB-4 Shield Tunnel and Velocity Selector Shielding Installed.* A
    great deal of neutron shielding is required to shield the exit of
    the new HFIR cold source and components of the cold neutron
    beamlines. The first and largest general section of shielding for
    the new instruments was constructed. Also, the lead shielding for
    the velocity selectors for the two small angle neutron scattering
    (SANS) instruments was assembled. These components are essential for
    the new Center for Neutron Scattering cold neutron spectrometers.

    *SANS 1 Detector Tank and Internal Components Installed.* The
    largest component for the first Small Angle Neutron Scattering
    (SANS) instruments has been installed. This giant tank will contain
    the detector for this instrument. The 1 meter square detector will
    ride on rails inside the evacuated volume of the tank.

    *The Neutron Reflectometer Commissioned.* A new instrument, the
    neutron reflectometer, was commissioned for use in the general user
    program at the HFIR Center for Neutron Scattering. This machine is
    optimized for the studies of surfaces and interfaces. It is the
    fifth Cold Neutron Source instrument fully commissioned and will be
    used for the studies of polymers, biomaterials, thin solid films,
    and surfactants.

**Selected FY 2004 Scientific Highlights/Accomplishments\
\
Materials Sciences and Engineering Subprogram**

-   ***The Ultimate Analysis: Single-Atom Spectroscopy in Bulk
    Solids.*** A longstanding dream in materials sciences and
    engineering has been to see and study those specific individual
    atoms that are critical to bulk properties and to determine their
    location and active configuration. Now, through an enhanced scanning
    transmission electron microscope with improved optics, researchers
    are able to observe an individual atom within its bulk environment
    and characterize its chemical state via spectroscopic means,
    determining its valence and bonding with nearest neighbors. The
    advance was made possible by correction of lens aberrations in the
    electron microscope to give a smaller yet brighter beam with a
    diameter of approximately 1 Ångstrom. Single-atom sensitivity, the
    ultimate analysis, opens up all areas of materials science and
    engineering to fundamental investigations in a revolutionary way.

-   ***New Thin-film Texture Discovered with Potential for Nanotech
    Applications.*** One of the most fundamental structural properties
    of a thin film is its "texture," which is the orientation of
    individual grains with respect to the deposition substrate. Three
    types of texture are commonly observed: random, where no single
    orientation is dominant; fiber-texture, where the film grains are
    parallel to the growth direction, but random about that direction;
    and epitaxial, where the film orientation is fixed in three
    dimensions with respect to the substrate. The new, fourth type of
    texture, named axiotaxy, was observed in a number of thin film
    systems in which the film and substrate share a common plane
    orientation as a consequence of crystal lattice matching. This new
    texture provides a potential method for assembling large numbers of
    nanocrystals in regular patterns for nanotech applications.

-   ***Negative Refraction - New Frontier for Superlenses***. The first
    demonstration of negative and positive refraction of visible light
    at the same crystal interface was recognized as one of the "Top 15
    Physics News Stories of 2003" by the American Institute of Physics.
    Nature provides us with optical refraction which is always positive:
    that is, the incident and transmitted light through an interface of
    two different media are on opposite sides of the interface normal.
    For negative refraction, they are on the same side of the interface
    normal. The beauty of negative refraction is total transmission and
    zero reflection, regardless of the angle of light incidence. These
    properties lend themselves to the creation of "super lenses." Laser
    beams can be steered in nano-photonic devices without loss, and
    optical telescopes can be built with higher resolution. The new
    interface uses a ferroelastic twin domain boundary such as a yttrium
    vanadate (YVO4) bi-crystal and is applicable to any frequency of the
    electromagnetic spectrum. As a vision for the future, electron beams
    could be focused more efficiently in highly sensitive electron
    microscopes.

-   ***Multi-band Semiconductors for High Efficiency Solar Cells.*** A
    new semiconductor material has been discovered that has multiple
    energy gaps, instead of the usual one, allowing for ultra-efficient
    energy capture of sunlight. Multi-band semiconductors were
    theoretically predicted over 20 years ago, but only now through the
    properties of so-called "highly mismatched alloys" (HMAs) have they
    been achieved. HMAs are compound semiconductors in which a small
    fraction of the anions are replaced with more electronegative atoms,
    producing a material with a new band having a strong quantum
    mechanical interaction with either the occupied valence band or the
    empty conduction band of the host semiconductor. Using this approach
    it was predicted, and subsequently demonstrated experimentally, that
    a II-VI semiconductor compound (ZnMnTe) with a small fraction (\~1%)
    of the group VI constituent, i.e., tellurium, replaced by oxygen
    operates as a multiband semiconductor. Theoretical evaluation
    indicates that a single junction solar cell fabricated from this
    material could achieve a power conversion efficiency of 56%.

-   ***Individual Carbon Nanotubes as Nanoscale Light Sources.*** A
    single carbon nanotube with a diameter of only 1.4 nanometer was
    used to fabricate the smallest source of light that can be
    controlled by electric current. The emission spectrum (color) of the
    light varied as a function of nanotube length and diameter. The
    center of the spectrum is determined by the nanotube diameter while
    the width of the spectrum depends on the length of the nanotube.
    Long nanotubes (50,000 nanometers) had narrow, symmetric emission
    spectra (characteristic of cold electrons) centered at the bandgap
    of the nanotube, which is inversely proportional to the nanotube
    diameter. Short nanotubes (500 nanometers) were also peaked at the
    bandgap of the nanotube, but showed broad, asymmetric spectra with a
    tail on the high-energy side, characteristic of hot electrons. These
    spectra show the cooling of hot electrons in nanotubes as a function
    of length through excitation of vibrations of the nanotube. The
    demonstrated understanding and control of optical properties using
    nanotubes could be important for optoelectronic nanotechnology.

-   ***Magnetic Resonance Imaging at the Nanoscale.*** An innovative
    magnetic resonance approach to characterizing nano-porosity in a
    variety of materials has been developed. Magnetic resonance imaging
    (MRI) has been tremendously successful in visualizing resident
    deformities and the presence of disease in soft, porous biological
    tissues of the liver or kidney, yet the limited resolution precludes
    characterization at the nanometer scale. By using a technique of
    percolating inert gas through a nanoporous structure and then
    determining both the \"sticking coefficient\" of the gas and the
    time it takes for the gas to move away from the pore structure, MRI
    can now evaluate both the pore size distribution and the nature of
    the pore connectivity. This allows the analysis of highly porous
    structures that are present in many living systems and those created
    artificially in the laboratory such as filters to sequester
    pollutants, catalysts for chemical reactions, highly efficient
    insulators, and high strength to weight ratio materials for
    structural applications. By understanding the relationship between
    processing parameters and porosity of the resultant materials,
    advances in porous materials can be made.

-   ***Nano-Trains: Nanoparticle Transport Using Motor Proteins.*** An
    active transport system that can be used to pick up, transport, and
    deposit nanoparticles within a microfluidic system has been
    developed. The active transport system is powered by the motor
    protein kinesin, a naturally occurring molecular machine. In the
    presence of a fuel source (adenosine triphosphate, or ATP), the head
    groups in the motor proteins "walk" rapidly along protein fibers
    called microtubules. With the tails of kinesin fixed to a surface
    the proteins can be used to propel the microtubules across the
    surface. The microtubules can now be modified to carry various size
    particles, ranging from 10 micrometers to 10 nanometers, and in
    large quantities, by functionalizing segments of the microtubules to
    carry cargo, like train "cars," while leaving other segments
    unfunctionalized to act as "engines" by allowing free interaction
    with the motor proteins. This discovery suggests that highly
    non-equilibrium structures could be developed using the same active
    transport strategies that organisms employ for tissue assembly and
    muscle actuation.

-   ***How Do Complex Fluids Jam?*** Is the mechanism for flow jamming
    the same for solid particulate matter (such as powders, coal, grain,
    pills, etc.) as for foam (bubbles in a fluid)? Two processes that
    rely on flowing foam are oil extraction and mineral separation. A
    major feature of both is that the flow can spontaneously stop, or
    jam, as the bubbles block each other. A better understanding of the
    causes of jamming will improve processes relying on flow. Recent
    studies using model foam systems have measured the coexistence
    between a flowing phase and a jammed phase. A surprising result was
    that this behavior was different from jamming observed in solid
    particulate systems. It provided evidence for at least two different
    mechanisms of jamming, a critical step in furthering the
    understanding of the jamming process.

-   ***Electron Transport in Semiconductor Quantum Wires.*** Spintronics
    (electronic phenomena that depend on electron spins) may provide a
    route to future generations of high-speed, low-power,
    nanoelectronics and may open up new areas of technology such as
    solid-state-based quantum computing. Significant challenges exist to
    realize these goals, including how to detect -- or read -- the
    electron spin in an electrical measurement. It has recently been
    demonstrated how such detection can be achieved in practice by
    exploiting the unique features of electron transport in
    semiconductor nanostructures known as quantum wires. Experiments
    show that the spin state of one quantum wire can be detected by
    studying the conductance of another wire located in close proximity.
    Theoretical work supports the idea that these experiments provide
    non-local detection of the electron spin opening pursuit of
    applications of this work to solid-state approaches to quantum
    computing.

-   ***Superfluid Excitons at High Magnetic Field.*** A grand challenge
    for condensed matter physics is the observation of a new phase of
    matter created by the "condensation" of excitons, which are
    electron-hole pairs. Because excitons are bosons, any number can
    occupy a single quantum state. Thus, at low temperature, they should
    condense into the lowest energy level. Unfortunately, observation of
    this has been hindered by the rapid recombination of the electron
    and hole. Using magnetic fields to create stable exciton gases in
    doped double-layer semiconductor structures, the first evidence for
    condensation of an exciton gas was found in quantum tunneling
    measurements. The signature of the condensation was that both the
    conventional and Hall resistances of the sample become extremely
    small at low temperature. This nascent superfluidity is the
    strongest evidence yet for excitonic Bose condensation.

-   ***Going from Good to Great: Doubling the Superconducting Upper
    Critical Field of Magnesium Diboride.*** In January 2001, a simple
    compound, magnesium diboride (MgB~2~) was discovered to superconduct
    at a remarkably high temperature of 40 K, double the 20 K value for
    the niobium-based industrial standard. However, in its pure form,
    the material stops superconducting in a low magnetic field. During
    the past year, it was determined that the material continues to be
    superconducting in high fields if a small amount of carbon, about
    5%, is substituted for boron. This has led to a better understanding
    of the superconductivity in this unique compound. The results
    indicate that, if the current carrying capability and mechanical
    properties can be further enhanced, carbon-doped MgB~2~ could become
    the next industrial standard superconductor \--better, cheaper, and
    lighter than niobium alloys.

-   ***Wiring for Nanocircuits: Stabilized Silicon Nanotubes.*** Recent
    theoretical predictions have indicated that silicon nanotubes can be
    stabilized by attaching a string of 3d transition elements along the
    outside of the tube. These same calculations predict that the
    resulting nanotubes will be strongly conducting \-- an important
    property needed by a candidate material for wiring together
    nanoelectronic components. The often considered carbon nanotubes,
    however, can be weakly metallic, semiconducting, or insulating
    depending on a property that is quite difficult to control-the
    winding ratio of the tube. The stabilization and metallization of
    the silicon nanotube can be accomplished with a small amount of
    nickel, about one nickel atom for every five silicon atoms. The
    compound tube structure studied is also smaller than most carbon
    nanotubes.

-   ***Lashing Together Nanoparticles to Make Real Things.*** Theorists
    have shown that one can cause nanoparticles to self-assemble into
    ordered arrays by attaching short polymer strings to the particles
    to act as tethers. This is important because it is necessary to
    assemble large numbers of nanometer-sized particles to create
    something of size appropriate to our world. It must be done as a
    loose assembly of the nanoparticles to retain their special
    properties but often also be arranged in special geometric patterns
    to realize the desired property. The technique demonstrated by
    detailed simulations is to attach short polymer strands to the
    particles at specified points and then let nature take its course.
    While currently only a theoretical prediction, the scheme is quite
    feasible and is expected to be in use within two to five years. In
    the meantime, the theorists are busy developing a "handbook" of how
    to position the tethers, how long they should be, and what they
    should be made of to accomplish a particular desired structure.

-   ***A New Class of White Light Phosphors: Advancing the Solid State
    Lighting Initiative.*** A new class of tunable, white light emitting
    phosphors based on single size semiconductor nanoparticles or
    quantum dots (QDs) has been discovered. This breakthrough meets one
    of the most critical needs in the Department's Solid-State Lighting
    Initiative, whose aim is to replace present day highly inefficient
    light bulbs by solid state lighting devices and thereby have
    revolutionary effects on conserving electric energy. This
    accomplishment was made possible by the finding that, for
    sufficiently small cadmium sulfide and cadmium selenide QDs of
    diameters two nanometers or less, the onset of light absorption
    (determined by dot size) and the emission energy, or color
    (determined by interfacial chemistry), can be independently
    controlled. The decoupling of these two features allows wide
    separation of the absorption and emission to eliminate
    self-absorption of the emitted light, and allows one to tune the
    emission throughout the visible range from a population of
    single-size dots. Key to this discovery is the ability to tailor the
    energies and lifetimes of interface states by the addition of
    suitable surfactants that bind to selected sites on the QD surface
    (which determine the emission), or the addition of suitable electron
    or hole traps (e.g., zinc or sulfide ions, respectively).

-   ***Catalyst Active Sites Imaged in Real Time.*** The atomic-scale
    formation and dynamics of active sites on a catalytic surface have
    been imaged for the first time. Using movies made from a series of
    state-of-the-art atomic-level scanning tunneling microscope images,
    the time-dependent behavior of sites on the surface of palladium
    metal was observed while diatomic hydrogen gas was adsorbed and then
    dissociated into two hydrogen atoms. The catalytic dissociation of
    hydrogen on a metal surface is pervasive in catalytic chemistry.
    Contrary to the prevailing view of the past three decades, it was
    found that three adjacent and empty surface sites are required for
    this process to occur - two empty sites are not sufficient. This
    surprising result calls into question the conventional thinking on
    the structure of active sites on catalyst surfaces. Further
    real-time measurements will help establish the molecular-level
    understanding of the formation of the active sites that determine
    the catalytic activity of a surface.

-   ***Basic Research Leads to Terabit Memory Devices.*** A decade-long
    basic research project has led to the first successful application
    by industry of a novel approach in nanotechnology, 'molecular
    self-assembly,' to enable continued miniaturization of semiconductor
    circuitry such as FLASH memories. The essential element in this new
    approach lies in directing the orientation of highly-dense arrays of
    nanoscopic cylindrical domains in thin films of diblock copolymers
    (BC). Using routine lithographic processes, the BC films are
    transformed into large area arrays of cylindrical nanopores with
    very high aspect ratios. Establishing the ability to produce such
    high density arrays in a simple, robust, and inexpensive manner
    using conventional processing (new tooling is not required and will
    not be required with further advances in the self-assembly
    technique) has broken new ground in fundamental studies of
    nanoscience and the rapid transfer of this technology to the
    industrial sector.

-   ***Fundamentals of How Liquid Metals Solidify Answered with
    Synchrotron Radiation Experiments.*** Materials properties are
    determined, in large measure, by the nature of the solidification
    process. During the cooling process, the metal atoms in the liquid
    phase are thought to pack together with almost the same order as the
    resultant solid. In fact, early experiments demonstrated that
    liquids cooled far below their melting point still maintain a large
    degree of disorder. As the temperature is further lowered, a well
    ordered crystalline solid is eventually reached, but the nucleation
    pathway to the crystalline form remained a mystery. By combining
    levitated molten metal drops with a newly developed, in-situ
    synchrotron x-ray diffraction technique for measuring structure
    during solidification, investigators have verified for the first
    time that atoms in a liquid metal arrange themselves with the local
    symmetry of an icosahedron, a Platonic solid consisting of 20
    tetrahedra (4-sided pyramid shaped polyhedra). As cooling proceeds,
    the icosahedral arrangement transitions to the final crystalline
    form. This discovery proves that atomic scale structure in the
    liquid actually plays a role in crystallization, something that is
    not treated in current nucleation theory.

-   ***X-Ray Microscopy in 3D on a Micron Scale***. Metal deformation,
    ranging from the centuries old heating and beating of sword edges to
    the rolling of metal sheets in modern industrial mills, is one of
    the oldest and most important materials processing techniques, yet
    it remains one of the least understood. Although elaborate recipes
    have been developed to produce alloys with desired properties, they
    are all based on expensive and inefficient search and discovery
    methods. To address this, a new, nondestructive,
    submicron-resolution 3D x-ray microscopy technique with
    high-precision nanoscale indentations to study the fundamental
    aspects of deformation in ductile materials has been developed.
    X-ray microscopy measurements made using penetrating synchrotron
    x-ray microbeams are providing detailed, quantitative information on
    the deformation microstructure for sizes below that of a human hair,
    but too large for electron microscopy. These results provide
    previously missing information that is critical for testing advanced
    theories and computer modeling and for making new materials, with
    predictable properties, in a more efficient manner.

-   ***Understanding Fundamental Magnetic Properties Could Lead to
    Sensor Development.*** Magnetic excitations provide insight into the
    spin structure and spin dynamics of materials. One material studied
    exhibits colossal magnetoresistance, a property that makes it
    interesting for sensor applications. The magnetic structure of this
    material (Pr~0.5~Sr~0.5~MnO~3~) was determined to be
    ferromagnetically aligned layers that are coupled
    antiferromagnetically. The magnetic excitations (also called spin
    waves) were measured using inelastic neutron scattering at the High
    Flux Isotope Reactor at Oak Ridge National Laboratory. The spin wave
    dispersion follows the behavior expected from linear spin wave
    theory. With refinements in analyzer efficiency and film preparation
    techniques, the measurement technique will then be applied to thin
    films. This should allow a search for spin wave excitations in
    antiferromagnetic films of Fe-Pt.Bose

    **Chemical Sciences, Geosciences, and Energy Biosciences
    Subprogram**

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-   ***Potential for Greatly Enhanced Efficiency in Nanocrystalline
    Solar Cells.*** An incident solar photon striking a semiconductor
    solar cell normally produces a single electron-hole pair (exciton)
    and some excess heat. Experimentalists have recently demonstrated
    that two or more excitons can be created by absorption of a single
    photon in an array of lead-selenide nanocrystals. This process is
    called "impact ionization" and is observed when the photon energy is
    greater than three times the band gap of the nanocrystal. Multiple
    excitons from a single photon are formed on the picosecond time
    scale, and the process occurs with up to 100% efficiency depending
    on the excess energy of the absorbed photon. If this process could
    be translated into an operational solar cell, the gain in efficiency
    for converting light to electrical current would be greater than
    35%.

-   ***High Order Harmonic Generation Using Ions.*** High harmonic
    generation (HHG) is a process in which highly nonlinear optical
    effects, driven by ultrafast, intense laser pulses in an atomic gas,
    are used to turn visible bursts of photons into bursts in the
    extreme ultraviolet and soft x-ray spectral regions. There is a
    cutoff at high frequencies for HHG that is determined by the
    ionization potential of the atom and by defocusing and phase
    mismatch of the pump-laser beam due to ionization. Recent
    experiments have significantly extended the range of HHG to photon
    energies up to 250 eV through the use of atomic ions, which have
    higher ionization potentials and are thus capable of producing more
    energetic harmonic orders. In this work an ultrashort, intense
    optical laser pulse was focused into a hollow fiber filled with
    low-pressure argon gas. The fiber serves as a waveguide to
    phase-match the fundamental excitation pulse with the HHG soft x-ray
    pulse. This work demonstrates that HHG from ions can extend
    laser-based, coherent up-conversion into the soft x-ray region of
    the spectrum.

-   ***Manipulation of Carbon Monoxide Oxidation to Carbon Dioxide***.
    The formation of a chemical bond involves the approach of two
    reactants to short distances so that a new bond can form. How close
    do the two reactants need to be for them to interact with each
    other? In this novel experiment, a single carbon monoxide (CO)
    molecule on a surface was pushed toward two oxygen (O) atoms that
    were formed in the dissociation of O~2~ by tunneling electrons.
    Using inelastic electron tunneling spectroscopy in a cryogenically
    cooled microscope, the hindered rotational mode of the CO molecule
    was measured as its distance from the two O atoms decreased. The
    change in this vibrational energy signaled the onset of a
    significant CO-O interaction prior to the formation of carbon
    dioxide (CO~2~). A shift of 20% in the hindered rotation energy was
    observed when the CO molecule was within 2.50 Å from each of the two
    O atoms. Spatially resolved mapping of the hindered rotational mode
    led to a tilted CO in the O-CO-O complex. The controlled positioning
    of the two reactants allowed direct visualization of the chemistry.
    This research probed individual reactive encounters of the type that
    constitute a surface-mediated catalytic process. Exacting control of
    catalysis will require such molecular-level characterization.

-   ***Direct Numerical Simulations of Homogeneous Charge Compression
    Ignition.*** Homogeneous charge compression ignition (HCCI) has the
    potential to reduce nitrogen oxide and particulate emissions from
    internal combustion engines while improving overall efficiencies. A
    major challenge posed by this method of combustion is control of the
    heat release rate, and in particular, a means to spread the heat
    rate out in time to suppress the occurrence of damaging engine
    knock. Direct numerical simulations (DNS) of lean hydrogen-air
    ignition at high pressure and constant volume in the presence of
    temperature inhomogeneities are helping researchers understand the
    HCCI combustion process. Starting from an initial distribution of
    fluctuating temperatures at high pressure, the evolution of
    localized ignition sites was studied in a constant volume DNS with
    detailed hydrogen/air reaction kinetics. For the first time,
    numerical simulations revealed that flame front and spontaneous
    ignition propagation can coexist in this environment. The
    simulations showed that the local nature of the ignition propagation
    is primarily dependent upon the inverse of the local temperature
    gradient. Criteria were developed from the DNS data (e.g., speed of
    the ignition front and a critical temperature gradient at the front)
    to distinguish between the different modes of propagation.

-   ***Charge Separation by Carbon Nanotube/Ferrocene Nanohybrids.***
    Carbon nanotubes, which are chemically stable and electrically
    conducting, have been modified for the first time by attachment of
    electron donors, in this case, ferrocene molecules. When excited
    with visible light, these carbon nanotube-ferrocene hybrids exhibit
    intramolecular electron transfer to yield long-lived
    charge-separated species. The carbon nanotube serves as the electron
    acceptor in the donor-acceptor ensemble, distributing the charge
    over its extended π-electronic system. The separation of charge is
    sufficiently long lived to show promise for future development of
    solar photoelectrochemical cells based on modified carbon nanotubes.

-   ***They Bend Before They Break: Fast Scission of Chemical Bonds.***
    Bond-breaking reactions in liquid solution which are so fast that
    the rates could not previously be measured, have recently been
    studied at the new picosecond Laser-Electron Accelerator Facility
    (LEAF) at Brookhaven National Laboratory. A large class of molecules
    known as aryl halides was studied, in which a halogen atom, such as
    chlorine or bromine, dissociates from a sizable planar ring
    structure, breaking its bond. The newly measured rates can only be
    explained theoretically if the bond breaks by the halogen atom
    bending out of plane by about 30 degrees before bond breaking, in a
    bent transition state. Such fundamental knowledge of the reaction
    mechanism may lead to improvements in energy efficiency and fewer
    toxic by-products in large-scale industrial processing.

-   ***Protein-Nanoparticle Hybrid Systems for Light Energy
    Conversion.*** Novel protein-nanoparticle hybrid assemblies have
    been developed that employ semiconductor nanoparticles for initial
    light-induced charge separation and biomolecules for subsequent
    chemical/electrical conversion. The end-to-end, wire-like nanorod
    structures are based on nanoscale metal oxide particles, in which
    the ability to systematically manipulate size and shape of the
    nanoparticles was exploited in synthesis of axially anisotropic
    tubes, cubes, rods, or stars. The nanoparticles were oriented into
    organized architectures using biolinkers, such as the biotin
    molecule, that bind strongly to the protein, avidin. Photoexcitation
    of the wire-like architecture resulted in charge separation
    originating at the tips of the nanorods: the photogenerated
    electrons being localized at the semiconductor, and holes at the
    protein. Thus, a rational design of protein-nanoparticle hybrid
    architectures enables coupling of photoinduced charge separation in
    nanocrystallites with the charge-transfer induced chemistry on
    proteins. The hybrid architectures and ensuing chemistries can
    either use or alter protein functionality, and could be used for
    construction of solar-based molecular machines.

-   ***Reverting Carbon Dioxide into Valuable Chemicals.*** An
    inexpensive, low-temperature synthetic route for the conversion of
    carbon dioxide into useful chemicals and fuels is a long-standing
    challenge. Despite extensive research, current catalysts still use
    expensive complexes of platinum-group metals. Recent work has led to
    a breakthrough in the catalytic addition of hydrogen to carbon
    dioxide to produce formic acid. Using sophisticated high-throughput
    techniques to rapidly search for promising catalytic structures,
    investigators have identified the broadest range to date of
    hydrogenation catalysts that can sustain high activity for many
    cycles. These structures consist of phosphine-complexes of copper,
    chromium, iron, indium, molybdenum, niobium, nickel, or tungsten,
    all of which are abundant and inexpensive metals. Detailed
    structural and mechanistic studies have led to even further
    improvement of the activity and durability by surrounding the metal
    centers with ligands designed to provide optimum electronic
    structure while protecting the metals from degradation. The new
    nickel, copper, and iron phosphine-cyano complexes carry out the
    production of formic acid at 40 bar and 50 ^o^Celsius with limited
    deactivation for periods of days.

-   ***Pure Hydrogen from Alcohol through Microsecond Catalysis***.
    Researchers have recently shown that it is possible to selectively
    extract pure hydrogen from ethanol, a renewable fuel made from
    biomass, in a matter of microseconds. The process is based on a
    high-temperature ceramic catalyst containing rhodium metal and
    cerium oxide. At about 800 ^o^C, wet ethanol, contacted with the
    catalyst for about one microsecond, undergoes oxidative
    dehydrogenation to hydrogen and carbon dioxide, with 95% conversion
    and 100% selectivity to hydrogen. This remarkable catalytic
    performance and the low-cost wet alcohol source could result in an
    economically feasible hydrogen production process for the future,
    especially as many of these very rapid oxidation reactions are
    self-sustaining even at 800 ^o^C or higher and do not require
    external heat sources. Advances in this hydrogen production process
    might provide an alternative to steam reformation of hydrocarbons as
    a source of hydrogen.

-   ***Benign Polymerization Chemistry Leads to New Polymers.*** The
    demand for polymeric materials continues to rise at an impressive
    rate and, in the near future, environmental conservation may become
    a major constraint in this expansion. Researchers have long pursued
    catalysts that take molecules derived from biomass, such as sugars,
    alcohols, and esters, and convert them with high yield and no waste
    into synthetic plastics, such as polyethers, polyesters, and
    polycarbonates, with controlled characteristics. Besides having
    appropriate thermal and mechanical properties, a significant
    fraction of future polymers should be biodegradable or biocompatible
    for use in large-scale packaging or in smaller-scale biomedical
    applications: drug release membranes, synthetic tissue, and sutures.
    Recently, investigators have successfully synthesized a family of
    metal alkoxide catalysts that produce polyesters and blends via
    ring-opening polymerization of cyclic esters derived from renewable
    sources. Examples are the synthesis of polylactides from lactides
    derived from corn and the formation of polycarbonates by
    ring-opening copolymerization of epoxides-oxiranes and carbon
    dioxide. The latter is a chemically benign alternative to the
    current technology for polycarbonate synthesis that uses phosgene, a
    highly poisonous gas. Through mechanistic, microstructural, and
    kinetic studies, these investigators are arriving at fundamentally
    new rules and new catalysts for transformations of oxygenated
    molecules that may dramatically change the landscape of
    polymerization chemistry.

-   ***Fundamental Studies on Crown Ethers Benefit Cleanup of Nuclear
    Waste at Savannah River.*** Fundamental research has provided the
    foundation enabling innovative technology for nuclear-waste cleanup
    at the Savannah River Site (SRS). In early 2004, a large contract
    was awarded for the design, construction, and commissioning of the
    Salt Waste Processing Facility (SWPF) to clean up a major portion of
    some of the nation\'s most dangerous Cold War era nuclear waste
    stored at the SRS. Approximately 34 million gallons of waste from
    nuclear-weapons production are stored in tanks at the SRS. Over 31
    million gallons of that waste is solid or dissolved salts in which
    the fission product cesium-137 comprises more than 98% of the total
    radioactivity in the salt. In 2001, the Office of Environmental
    Management chose the Caustic-Side Solvent eXtraction (CSSX) process
    developed at Oak Ridge National Laboratory for removing cesium-137
    from the waste in the SWPF. The selection followed an intensive
    period of evaluating candidate technologies by a multi-site team of
    scientists and engineers over a four-year period. Selection was
    based on the ability of candidate technologies to meet difficult
    processing requirements, including the ability to remove 99.9975% of
    the cesium-137 from the waste. Such extraordinary performance
    requires extraordinary chemistry, which had its roots in fundamental
    research which focused on the principles of host-guest chemistry,
    emphasizing the synthesis of tailored molecules that selectively
    bind (or host) target species. The understanding of host-guest
    chemistry from this research led to the ability to design the
    synthesis of crown ethers with appropriate architecture to complex
    with alkali metal ions to effect extraction with high selectivity.

-   ***Improved Analysis for the Next Generation of Electronic
    Devices.*** New research has shown that by covalent Fluorescent
    Labeling of Surface Species (FLOSS), the inherent sensitivity of
    fluorescence spectroscopy can be exploited to identify and quantify
    low concentration functional groups on surfaces. FLOSS enables the
    detection of surface chemical groups as low as 1011 molecules/cm^2^
    (0.01% of the surface) by specific covalent attachment of
    fluorescent chromophores to surface functionalities. Advances in
    electronics and sensors have been made by decreasing the size of the
    components making electronics faster and sensors more sensitive and
    selective. These advances provide an important step in our ability
    to control size and thickness of insulating layers for modern
    electronic devices. The technique used to develop these films is to
    expose the surface, such as silicon, to a long chained molecule, and
    allow it to self assemble on the surface. The length of these chains
    can then be reduced to control the resistivity by reaction with
    electrons or ozone, and the pattern they make on the surface can be
    controlled by ion or electron bombardment using a mask or laser
    ablation by rastering the beam across the surface. Understanding and
    controlling the chemistry of these reactions is critical to make the
    next generation of devices.

-   ***Building Polar Actinide Materials.*** Compounds that adopt polar
    structures are able to exhibit a wide range of important
    technological properties such as second-harmonic generation
    (nonlinear optics), piezoelectricity, and pyroelectricity. One
    strategy for constructing polar structures is to use oxoanions
    containing heavy atoms such as selenium, tellurium, and iodine.
    These oxoanions share a common feature: they contain a nonbonding
    pair of electrons that can be aligned during crystal formation to
    create polar structures. These anions have been combined with the
    actinide elements uranium, neptunium, and plutonium to create novel
    polar actinide materials. Some of the neptunium compounds are
    further unusual in that the distance between neptunium atoms within
    the crystals can be controlled, allowing magnetic interactions to
    take place between the actinide elements. This work allows detailed
    structure-property relationships to be developed in polar actinide
    materials. These relationships elucidate the properties of 5f
    electrons, which contribute uniquely to the bonding in actinide
    materials and provide models for polar materials of nonradioactive
    transition metals.

-   ***Plutonium Oxide Unraveled.*** A collaboration of research groups
    has developed sophisticated quantum chemistry software to model the
    electronic properties of actinide materials. These computational
    programs solve the first-principles, basic equations governing the
    quantum mechanics of electrons and nuclei, to yield predictions
    about conducting properties, equilibrium structure, and other
    electronic properties of materials like plutonium oxide (PuO~2~). In
    a recent series of calculations on a cluster of high-performance
    computers, it was predicted for the first time that PuO~2~ is an
    insulating material with a band gap of a few eV and with ferro- and
    anti-ferromagnetic phases in close energetic balance. These results
    are consistent with subsequent experimental data obtained by other
    researchers. A successful description of electronic properties of
    PuO~2~ is a prerequisite for more elaborated modeling of the
    interaction of PuO~2~ surfaces with water and other environmental
    species. Understanding these basic processes is essential to predict
    the long-term stability of PuO~2~ when it is exposed to air, water,
    and other common substances.

-   ***Bioelectrochemistry on Nanostructured Surfaces.*** A defining
    feature of modern bioelectrochemistry is extraction of functional
    biomolecules and their reconstitution on patterned surfaces in
    defined geometries. The bioelectrochemical process of solar energy
    absorption and subsequent conversion of light energy uses two
    molecular reaction centers operating in series, Photosystems I (PSI)
    and II (PSII). Photon absorption triggers electron transfer
    reactions that generate an electric voltage. It is this
    electrochemical potential that is the source of free energy for
    conversion of light energy into chemical energy. It has been
    demonstrated for the first time that PSI molecules can be oriented
    by elementary dipole forces that exist at the air-water interface
    and the dipole points predominantly towards the water. Orientation
    was demonstrated by measurement of the magnitude and sign of the
    electrostatic potential above the PSI-containing air-water
    interface. Bioreaction centers supported in nanoporous media enable
    the construction of bioelectrochemical systems for both basic and
    applied needs.

-   ***Thermophysical Properties of Macromolecular Systems in Nanoscopic
    Structures.*** An important part of nanotechnology is to understand
    whether the properties of polymeric systems in nanoscopic structures
    are different from those of the bulk. Theoretical studies have
    established for the first time that nanometer-length structures of
    polymer glasses exhibit a glass transition temperature which is
    significantly lower than that of the corresponding bulk polymer.
    These studies also established that the elastic properties of the
    polymer in such structures are considerably "weaker" than those of
    the bulk. Finally, and perhaps most importantly, it has been
    demonstrated that the elastic moduli of nanoscopic polymeric samples
    are highly anisotropic, raising serious concerns about the
    applicability of continuum-mechanics computational approaches for
    study of such systems. These predictions indicate that the
    mechanical stability of features smaller than 50 nm is severely
    degraded. Extrapolation of current technology as applied in the
    microelectronics industry might not be possible.

-   ***Structure of Electric Double Layer at the Rutile Surface from
    Molecular Dynamics Simulations.*** Rutile (α-TiO2) is the protective
    surface phase that will cover the drip shields over the waste
    canisters at the Yucca Mountain waste repository. It is also an
    important mineral in the chemical and materials industries as a
    catalytic substrate, photocatalyst, pigment, and ceramic raw
    material. Molecular simulation of the structure of the relaxed
    rutile (110) crystal surface in contact with aqueous solutions were
    performed to determine the structure of water molecules near the
    interface, adsorption of ions, identification of several modes of
    binding of adsorbed ions with surface oxygens, and static and
    dynamic properties of the surface. Quantitative experimental data
    provided by synchrotron x-ray investigations determined the
    distribution of adsorbed water molecules and cations at the
    rutile (110) surface and verified the predictive capabilities of the
    computational approaches. Computational chemical physics
    demonstrated the utility of classical models of the macroscopic
    properties of the electric double layer. Solid-liquid surface
    properties (colloidal stability, structure of micelles, membranes,
    metallurgy, chemical sensors, catalysis, and synthesis of nanophase
    materials) can now be linked to the atomic-level structural
    information.

-   ***Water-Driven Structural Transformation in Nanoparticles at Room
    Temperature.*** Natural mineralogical nanoparticles exist at ambient
    temperature, pressure, and humidity in the geosphere. Research on
    nanoparticulate mineral phases provides understanding of the role of
    natural nanoparticles and in predicting what the future of "new"
    nanoparticles will be in the environment. Zinc sulphide
    nanoparticles (\~3nm, 700 atoms) synthesized in methanol exhibited a
    reversible structural transformation accompanying methanol
    desorbtion. The binding of water to the as-formed particles at room
    temperature led to a dramatic structural modification, significantly
    reducing distortions of the surface and interior to generate a
    structure close to that of the mineral sphalerite. This shows one
    route for post-synthesis control of nanoparticles structure, and the
    potential use of the nanoparticles' structural state as an
    environmental sensor. The results also demonstrate that the
    structure and reactivity of natural nanoparticles will depend both
    on the particle size and on the nature of the surrounding molecules.

-   ***A Molecular Switch Controls Cell Identity.*** Like its fuzzy,
    dwarf namesake from the "Star Wars" movie, the YODA (YDA) mutant in
    Arabidopsis is small but powerful. Recent molecular genetic
    experiments reveal that YODA acts as a negative regulator of plant
    cell fate decisions following asymmetric cell divisions. This
    regulation is essential for establishing normal cell patterns for
    stomata, tiny surface pores in leaves and shoots. Pore size is
    regulated by a pair of flanking guard cells that serve as gas valves
    controlling carbon dioxide and water vapor movement in or out of the
    leaf. Early in development these cells make an irrevocable decision
    on whether they will end up as epidermal cells, or undergo an
    asymmetric division and become guard cells. YODA's kinase activity
    sends the signal that decides this developmental fate, thus
    determining the number of stomates on a leaf surface. So as plants
    grow and form new leaves, they can adjust to factors such as carbon
    dioxide, and water and light availability by changing stomatal
    density and distribution. This illustrates how protein-gene
    interactions within complex regulatory feedback loops and pathways
    can be deciphered to understand how a group of cells can grow,
    develop, and adapt to an ever-changing environment in the
    coordinated form of a whole plant.

-   ***Structural and Functional Analysis of a Minimum Plant
    Centromere.*** Every chromosome, the carrier of hereditary
    information in all living organisms, contains three essential
    elements: the telomere ends, the origin of replication that
    initiates copying of genetic information, and the centromeres that
    direct the partitioning of chromosomes during cell division.
    Scientists have made a startling discovery about the nature of these
    centromeres in rice plants. Their sequencing of the centromere of
    rice chromosome 8 revealed the presence of four active, expressed
    genes. This discovery refutes long-held scientific beliefs that
    centromeres contained only structural information for chromosome
    segregation, programmed within vast stretches of "junk DNA"
    consisting of repetitive, rearranged and noncoding sequence tracts.
    This work, significant for being the first completely sequenced
    plant centromere, complements the international effort to complete
    the sequence of the rice genome, and represents the first step
    toward achieving such practical applications as the creation of
    artificial chromosomes for precision plant engineering.

-   ***The Glass Bead Game of Molecular Detection.*** A significant
    challenge in the study of biological systems is the ability to
    detect molecular interactions with sensitivity and accuracy.
    Scientists have developed a novel technique for detecting substrate
    binding to proteins embedded within cellular membranes. Their
    technique uses the fundamental qualities of colloidal particles,
    which self-assemble into a variety of ordered phases in a manner
    driven by the pair interaction potential between particles.
    Colloidal suspensions of membrane lipids linked to a specific
    substrate were coated onto silica beads. When a protein binds to
    this immobilized substrate, it causes small perturbations on the
    membrane surface that result in visible reorganization of the
    colloid, such that the coated beads disperse. The ability to sense
    molecular interactions without the use of expensive fluorescent
    probes has practical implications for rapid, high-throughput
    screening of a variety of interactions between biological molecules.

**Selected FY 2004 Facility Accomplishments**

-   **The Advanced Light Source (ALS)**

    *New Insertion Device Installed for Ultrafast X-Ray Pulses.* Light
    from a high-power, ultrafast laser will travel with the electron
    beam through the new permanent-magnet wiggler at the ALS, thereby
    modulating the energy of a portion of the electron beam. The energy
    modulation results in a spatial separation of the modulated slice of
    the beam, which is only 200 femtoseconds long, so that it can be
    used to generate ultrafast x-ray pulses for experiments at photon
    energies from 100 eV to10 keV.

    *High-pressure Facility Enables State-of-the-art Geophysics and
    Materials Research.* At the newly commissioned ALS research
    facility, x-rays from a superconducting bend-magnet source, a
    high-efficiency micro-focused beamline, and a high-power
    laser-heated high-pressure cell (diamond anvil cell) will be used
    for a wide range of experiments, such as determining the
    high-pressure/high-temperature phase diagrams and equations of state
    of materials at pressures up to the Mbar range and at temperatures
    up to several thousand Kelvin.

    *New Research on Solvated or Buried Systems Possible.* Real-world
    materials that inhabit wet environments or are buried in the
    interior of more complex structures pose challenges to researchers.
    *In situ* electronic and structural properties of such materials are
    now accessible due to the high brightness of third-generation
    synchrotron radiation sources and the development of liquid-cell
    sample chambers. The technology developed at the ALS has already
    been demonstrated for the characterization of nanoparticles and
    opens the way for studies of advanced battery and hydrogen storage
    material.

    *Fast Orbit Feedback Stabilizes Electron Beam Position.* Today's
    synchrotron radiation instrumentation requires that the position of
    the illuminating x-ray beam be rock solid, which in turn imposes the
    same condition on the position of the electron beam. ALS scientists
    and engineers have commissioned a new feedback system (fast orbit
    feedback) that senses the beam position and sends signals to the
    control system to correct any vertical and horizontal position
    errors to within 2 µm and 3 µm, respectively.

-   **The Advanced Photon Source (APS)**

    *A New Technique for Understanding Materials under Extreme
    Conditions.* Nuclear resonant inelastic x-ray scattering and
    extreme-brilliance x-ray beams are being used to measure, for the
    first time, the velocity of sound in tiny samples of materials under
    extreme conditions. The ability to obtain detailed information from
    minuscule amounts of materials under extreme conditions is critical
    to many experiments, from geophysics to national security.

    *Taking the Heat from Higher-Brightness X-rays.* Two new beamlines
    require two or three in-line undulators to achieve the required high
    photon intensity. To accommodate the expected higher APS storage
    ring beam current and concurrent heat loads that will be more than
    three times hotter than the surface of the sun, a novel insertion
    device front end has been developed.

    *Powering Up to Higher X-ray Beam Brilliance.* Radio frequency (rf)
    technology at the APS is one of several innovations laying the
    foundation for an eventual increase in storage ring current to 300
    mA. This power exceeds the rf output power of all the TV and radio
    stations in a major U.S. city such as Washington, D.C., and will
    provide researchers with more brilliant x-ray beams.

    *Glowing Results from a Unique Application of X-ray Fluorescence.*
    The intense photon flux from an APS insertion device beamline has
    been used for the first application of x-ray-induced fluorescence
    techniques to perform in-situ measurements in high-pressure
    metal-halide arcs. These data, not obtainable in any other way, are
    essential to developing a clearer understanding of high-pressure arc
    systems, among the most energy-efficient sources of white light.

-   **The National Synchrotron Light Source (NSLS)**

    *Superconducting Undulator Test Facility Constructed.* A
    state-of-the-art cryogenic Vertical Test Facility was designed and
    constructed for use in developing superconducting undulators (SCU).
    This device allows precise magnetic field mapping of superconducting
    undulator prototypes at cryogenic temperatures and measures thermal
    performance and quench behavior under realistic operating
    conditions, including simulated beam heating. A SCU design has been
    developed which incorporates a novel cryogenic thermal management
    system to intercept the high beam heat loads expected in future
    ultra-high brightness synchrotron light sources.

    *Hard X-ray Microprobe Completed for Environmental Sciences.* A new
    hard x-ray microprobe beamline, X27A, will provide additional and
    enhanced x-ray micro-spectroscopy capabilities to the NSLS
    environmental science user community. The beamline can be operated
    in three different modes and can focus x-rays to a spot the size of
    a few microns. The detector array will enable both elemental mapping
    as well as fluorescence yield x-ray absorption spectroscopy studies
    of complex environmental samples.

    *Infrared Spectrometer Installed on Surface Science Beamline.*
    Corrosion and catalysis involves the interaction between gas
    molecules and another material such as a metal surface. Infrared
    spectroscopy from metal surfaces is an important tool for studying
    the interactions with adsorbed molecules. A portion of the U4IR
    surface science beamline was re-built to incorporate a new infrared
    spectrometer. This new spectrometer provides improved spectral
    resolution, spectral range, and increased collection rates over the
    previous instrument.

    *X-ray Beamline Renovated for Materials Sciences.* The X21 hybrid
    wiggler x-ray beamline and two experimental stations have been
    substantially rebuilt to accommodate new experimental programs that
    address elastic x-ray scattering studies of materials under high
    magnetic fields, thin films grown in-situ, and materials studied
    with small angle x-ray scattering, with appropriate setups
    permanently installed in the stations.

-   **The Stanford Synchrotron Radiation Laboratory (SSRL)**

    *SPEAR3 Project Completed.* The four-year SPEAR3 Upgrade Project,
    jointly funded by the Department of Energy and the National
    Institutes of Health, was completed on time and within budget (SPEAR
    stands for the Stanford Positron Electron Accelerating Ring). The
    3-GeV SPEAR3 light source produces x-ray beams having 1 to 2 orders
    of magnitude higher photon brightness than the SPEAR2 accelerator it
    replaced, enabling enhanced scientific capabilities comparable to
    those of other third generation light sources.

    *SPEAR3 Commissioned and Operation for Users Commenced.* The SPEAR3
    storage ring was commissioned within a remarkably short time,
    beginning with equipment turn-on in mid-November 2003, and ending
    with the first 100-mA beam delivery to users in early March 2004.
    The speedy commissioning enabled the SSRL user program to begin
    again only 11 months after the SPEAR2 shutdown.

    *First Diffraction Patterns are demonstrated with the SPPS.* The
    first measurements of diffraction patterns from several prototypical
    samples were achieved at the sub-picosecond pulse source (SPPS). The
    first signals from the electro-optic pulse length and jitter
    experiment have been recorded yielding resolution limited pulse
    lengths of 1 picosecond. The preliminary jitter results indicate
    root-mean-square timing of the order of 250-300 femtoseconds.

    *Source of Excessive Beam Emittance Found.* Important progress in
    understanding the sources of excessive electron beam emittance from
    a photo-cathode gun has been made at the SSRL Gun Test Facility,
    setting the path for achieving the design goal for the Linac
    Coherent Light Source (LCLS) electron gun. The discovery indicates
    that a time dependent kick significantly increases the projected
    beam emittance. Eliminating the beam kick will enable operation of
    the high-charge gun with a sufficiently low emittance for x-ray Free
    Electron Laser operation at the LCLS.

-   **The Intense Pulsed Neutron Source (IPNS)**

    *IPNS Instruments Upgraded.* The IPNS continues to make major
    instrument upgrades to maintain world class science capabilities for
    its users: 1) more than one half of the user instruments have
    migrated to a new data acquisition system that enables faster and
    more flexible data binning; 2) installation of neutron guides and
    frame definition choppers has boosted flux on sample for some
    instruments by 2-20 times; and 3) improved detectors and collimation
    and larger detector coverage have significantly reduced the time
    required to collect neutron data. Successful commissioning of a new
    IPNS target from recycled disks recovered from end-of-life targets
    has provided a cost effective alternative to the construction of
    entirely new IPNS targets and enables IPNS operations for an
    additional six years.

    *IPNS Hosts the National Neutron and X-Ray Scattering School.*
    During the two-week period of August 15-29, 2004, Argonne National
    Laboratory again hosted the National School on Neutron and X-Ray
    Scattering. The school continues to attract outstanding graduate
    students and post-doctoral appointees with 134 applications for the
    60 positions available in 2004.

-   **The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
    Neutron Science Center (LANSCE)**

    *Goniometer Installed on Small-Angle Neutron Scattering Instrument.*
    The goniometer is able to position the sample in the neutron beam
    with any orientation. Thus, it provides for a complete measurement
    of diffraction space, giving information on the crystal
    three-dimensional structure over large length scales from 1 to about
    100 nm. Research problems that will benefit from this new capability
    include flux-lattice studies in superconductors, super lattice
    structures, and self-assembling colloidal structures.

    *Spin Echo Spectrometry Demonstrated.* This technique, achieved for
    the first time at a pulsed neutron source, has application to
    diffraction problems in nanoscale materials systems and was
    demonstrated on a dilute solution of 58 nm diameter polystyrene
    spheres in deuterium oxide.

    *High-Intensity Powder Diffractometer (HIPD) Refurbished.* The
    instrument is now fully operational for studies of atomic and
    magnetic structure of crystalline and noncrystalline powders,
    liquids, phase transitions, small samples, and absorbing materials.
    Due to its very high counting rates, time-resolved measurements are
    also possible as recently demonstrated in a diffraction study of the
    curing process of cement.

-   **The High Flux Isotope Reactor (HFIR)**

    *Operational Milestone Celebrated.* On April 21, 2004, HFIR began
    its 400^th^ operating cycle in its 38 year history. The length of an
    operating cycle depends on the time it takes for the reactor\'s
    uranium fuel to become depleted. A celebration marking this
    anniversary was held on May 15.

    *Neutron Scattering Instruments Upgraded.* The upgraded HFIR has
    state-of-the-art neutron scattering instruments that are among the
    world\'s best. In FY 2004, the HB-2B Residual Stress Diffractometer
    was brought into operation in the HFIR Beam Room. The HB-2D
    triple-axis monochromator shield was installed at the end of the
    HB-2 tunnel, and the Reflectometer and SNS Detector Station on this
    beam tube are operational. The WAND diffractometer, one of the
    instruments in the US-Japan International Collaboration, will also
    be operational, completing an important milestone in the HFIR
    Upgrade project.

    *Cold Source Comprehensive Hazards Analysis Completed.* One of the
    premier features of the HFIR upgrade will be the addition of an
    environment of super-cold liquid hydrogen. This environment
    literally chills the neutrons so they have less thermal energy with
    longer wavelengths, which make them valuable tools for the study of
    larger, more complex atomic and molecular structures. The HFIR Cold
    Source Comprehensive Hazards Analysis was completed and submitted to
    DOE in support of the October 4, 2004 milestone.

    *Reactor Equipment Upgraded.* New Instrument Air System compressors,
    dryers and receivers were installed in FY 2004. These components
    replace obsolete equipment and will simplify the system by reducing
    the number of valves in the system significantly.

-   **The Combustion Research Facility (CRF)**

    *Sample Preparation Laboratory Ready for Advanced Microscopy.* A
    laboratory has been converted to a sample preparation space for the
    research activities in the Advanced Microscopy Laboratory. The new
    lab is equipped with instrumentation and supplies for preparing
    ultra-clean samples critical to single molecule imaging of
    biomolecules and nanomaterials.

    *Optically Accessible Engine Facility Established.* The facility's
    new automotive-scale Homogeneous-Charge Compression-Ignition (HCCI)
    engine provides versatile optical access, accommodating the study of
    combustion via a laser-based investigation of in-cylinder processes.
    The facility is well suited for the examination of advanced fuel-air
    mixture preparation strategies that have been proposed as a way of
    achieving the strong potential of HCCI engines.

    *New Instrument Developed to Investigate Complex Reaction
    Processes.* A new instrument consisting of an ion- and laser-beam
    surface analysis system coupled to time-of-flight and
    high-resolution Fourier Transform ion cyclotron resonance mass
    spectrometers has been built and tested. The instrument is used to
    investigate complex spatiotemporal reaction processes related to the
    aging of materials and biological processes at the cellular level.

    *New Laser Diagnostics Measure Diesel Particulate Emissions.*
    Laser-induced incandescence (LII) and Laser-Induced Desorption with
    Elastic Laser Scattering (LIDELS) are new diagnostic techniques that
    provide previously unobtainable time-resolved measurements critical
    for the optimization of engine performance. Real-time measurements
    are particularly crucial for the development of regeneration
    strategies for lean NO~x~ catalysts and diesel particulate filters.

**Selected FY 2003 Scientific Highlights/Accomplishments\
\
Materials Sciences and Engineering Subprogram**

-   ***Towards an Exciton Condensate -- A New Form of Matter.*** A
    Bose-Einstein condensate, a form of matter heretofore observed only
    in atoms chilled to less than a millionth of a degree above absolute
    zero, may now have been observed at temperatures in excess of one
    Kelvin in excitons, the bound pairs of electrons and holes that
    enable semiconductors to function as electronic devices. Researchers
    have observed excitons in a macroscopically ordered electronic
    state, indicating the formation of a condensate. The observations
    were made by shining laser light on specially designed nano-sized
    structures called quantum wells, which were grown at the interface
    between two semiconductors -- gallium arsenide and aluminum gallium
    arsenide. These quantum wells allow electrons and electron holes
    (spaces in the crystal that are positively charged) to move freely
    through the two dimensions parallel to the quantum well plane, but
    not through the perpendicular dimension. Under photoluminescence,
    the macroscopically ordered exciton state appeared against a black
    background as a bright ring that had been fragmented into a chain of
    circular spots extending out to one millimeter in circumference.
    Just as the Nobel prize-winning creation of Bose-Einstein condensate
    atoms offered scientists a new look into the hidden world of quantum
    mechanics, so, too, will the creation of Bose-Einstein condensate
    excitons provide scientists with new possibilities for observing and
    manipulating quantum mechanical properties. The observation also
    holds potential for ultrafast digital logic elements and quantum
    computing devices.

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-   ***Magnetic Nanocomposites: The Next Little Thing.*** Magnetic
    materials are indispensable to a modern industrial society; however,
    it is no longer possible to squeeze significantly better performance
    out of today's most advanced magnets. A new approach is to create a
    composite material of two magnetic materials combined on the
    nanoscale to create a material with better performance than either
    taken separately. The boundary between the two magnetic materials is
    exceedingly important. Studies of bilayers of magnetically-hard and
    magnetically-soft magnetic materials have revealed that diffusion
    between the two materials alters the interface between them,
    resulting in improved magnetic properties. Theoretical modeling
    confirms that interfacial modification can enhance interlayer
    magnetic coupling. The results reveal the potential of careful
    interfacial control for improving magnets through manipulation of
    the material at the nanoscale.

-   ***Tuning the Properties of Materials at the Nanoscale*.** As the
    size of silicon electronic devices shrinks toward the nanometer
    scale, the properties of the nanometer-thick silicon thin film in
    the devices depart from those of the bulk form of silicon.
    Nanostressors will be able to tune the properties of such thin
    films. For example, germanium islands grown on silicon act as
    nanostressors to shape the silicon film. The induced bending of the
    silicon film modifies the local electronic and optical properties of
    silicon. This ability to "tune" the properties of solid thin films
    is expected to become more prominent as semiconductor devices shrink
    to ever smaller scales.

-   ***New Nanoscale Structures Form where Grain Boundaries Meet
    Surfaces*.** A newly discovered nanoscale "defect" may be connected
    to unusual behavior of metal catalysts and thin films, which are
    critical to the chemical and electronic industries. A distinct
    channel with a V-shaped cross section has been observed along the
    intersection of a grain boundary with an external surface.
    Atomic-resolution observations of gold surfaces in combination with
    atomic-scale simulations show that this channel has a different
    crystal structure than the remainder of the material. One
    implication is that when the grains become sufficiently small, these
    channel regions may dominate the surface and result in very
    different reactivity and catalytic activity than expected based on
    the bulk structure. These channel defects may also pin grain
    boundaries, slowing or preventing their motion and affecting the
    processing of thin films for microelectronics. Furthermore, the
    channels can be thought of as naturally occurring nanoscale wires
    along the surface of a material, whose arrangement could be
    controlled by appropriate processing.

-   ***Imaging Single, Individual Molecules.*** By using a tightly
    focused beam of electrons less than a nanometer in diameter and by
    reconstructing images from the electron scattering data, the exact
    atomic positions in an individual carbon nanotube have been
    determined. Images of high resolution and high contrast can be
    obtained as has been shown by solving the structure of a single,
    double-walled carbon nanotube -- a very complicated problem
    involving one tube nested in another. The technique has the
    potential to allow imaging of atomic arrangements in individual
    non-periodic structures such as biological macromolecules.

-   ***Nanofluids Improve Heat Transfer.*** Suspensions of nanoscale
    metal particles or carbon nanotubes in fluids exhibit unusual
    enhancements in thermal conductivity. Picosecond measurements using
    laser techniques have been used to make the first quantitative
    measurements of heat transfer at the solid/fluid interface. Very
    large improvements for thermal conductivity are expected based on
    simple theory for carbon-nanotubes, but are not observed. The
    picosecond data shows that the thermal coupling between the nanotube
    and the surrounding matrix is weak, greatly impeding heat transfer
    in the carbon-nanotube composite. The results also indicate that the
    thermal conductance at the particle/fluid interface is highly
    sensitive to both structure and chemistry.

-   ***Silicon: From Information Age to an Efficient Light Emitter**?*
    Silicon is the bedrock on which the information age is built, but it
    is a notoriously poor light emitter. The holy grail of silicon
    technology is to make silicon an efficient light emitter so that
    digital information can be converted to light for the ultimate
    transmission speed across optical fiber networks. New calculations
    have shown that a novel impurity superlattice structure of
    thin-layer oxide could do precisely that by altering silicon
    electronic charge characteristics to couple directly to light. This
    breakthrough opens the door so that the light-emitting efficiency of
    silicon could be drastically enhanced. This discovery will
    dramatically impact the microelectronics industry by significantly
    reducing the cost and complexity associated with the integration of
    optoelectronics into silicon-chip products.

-   ***Synchrotron Light Sources Help Reveal Secrets of Welding**.*
    Welding is a critical metal joining technology used worldwide in the
    energy, automotive, aerospace, construction, and chemicals
    industries. Rapid cooling during welding induces numerous phase
    changes in the metal. Theories have been developed to describe this,
    but they have never been verified experimentally. Time-resolved
    x-ray diffraction using synchrotron radiation has now been used for
    the first time to monitor in-situ phase evolution of a
    multi-component steel weld during melting and subsequent
    solidification. The results show that equilibrium theories applied
    to rapid cooling conditions are not valid for steel welds containing
    fast diffusing (carbon) and slow diffusing (aluminum) atoms. This
    new ability to observe the competition of multi-component phases at
    the microstructural level will make it possible to design stronger
    and tougher welds, chemically tailored for optimum performance.

-   ***Ultrathin, Laminar Films for Instantaneous Computer Boot-up.*** A
    new technique has been developed to deposit metal atoms onto thin
    oxide layers. This technique will help next-generation computers
    boot up instantly by making entire memories immediately available
    for use. The method anchors ultrathin metallic cobalt layers on
    sapphire by using a surface chemical reaction that overcomes an
    island formation problem that has long plagued researchers. The new,
    inexpensive trick to prevent island formation is as simple as
    exposing thin oxide films to water vapor before depositing the metal
    layer. The thin metal layer achieves crystallinity after the
    deposition of only a few atomic layers. This process should be
    applicable to a wide range of metals on metal oxides.

-   ***Novel Synthesis of Shape-Controlled Nanostructures.***
    Fabricating shape-controlled nanostructures such as nanowires and
    nanodots plays a central role in nanoscale science and technology. A
    novel electrodeposition process has been developed to self-assemble
    an array of nanostructures on flat surfaces. The new technique is
    based on the application of an electric field to ions on graphite
    substrates immersed in an aqueous solution. A large variety of
    voltage-controlled nanostructures have been grown such as cubes,
    pyramids, pentagons, hexagons, nanowires and snowflakes in
    superconductors and ferromagnets as well as in emerging application
    systems such as catalytic silver and hydrogen-sensing palladium.
    These unique nanostructures provide a new theater to explore shape
    effects on quantum confinement and present new opportunities for
    nanoelectronic applications.

-   ***Biomolecular Route to Photovoltaic and Semiconductor
    Nanocrystals**.* Biology exhibits a remarkable ability to control
    the nanostructures of materials, such as the exquisitely shaped
    microscopic shells of diatoms and radiolarians, with a precision
    that far exceeds the capability of present human engineering. Now,
    the biomolecular mechanism that directs the nanofabrication of
    silica in living organisms has been harnessed to direct the
    synthesis of photovoltaic and semiconductor nanocrystals of such
    materials as titanium dioxide, gallium oxide, and zinc oxide \--
    materials that biology has never used in structures before. Proteins
    from a marine sponge -- and their counterparts produced from cloned,
    recombinant DNA -- were used to catalyze and structurally direct the
    growth of the inorganic semiconductors at low temperature and under
    mild conditions, in marked contrast to the need for elevated
    temperatures and caustic chemicals presently required by
    conventional manufacturing methods. The nanocrystallites of gallium
    oxide formed in this process show a preferential alignment directed
    by the underlying proteins, revealing a template-like
    structure-directing activity of the biomolecules. Furthermore, the
    proteins working at low temperature produce and stabilize crystal
    forms of gallium oxide and titanium dioxide normally seen only at
    very high temperatures. Such biomolecular routes may lead to new,
    environmentally benign routes to semiconductor and photovoltaic
    materials with improved control over both nanostructure and
    performance, as well as improved interfaces between optoelectronic
    devices and living systems.

-   ***The Impact of a Single Atom**.* Never before has it been possible
    to identify single atoms within bulk materials and determine the
    influence of a single atom on its surroundings. Isolated atoms can
    significantly modify the physical properties of many of the
    technologically most relevant and scientifically interesting
    materials. While it has long been known that in semiconductors, for
    example, the presence of a single dopant atom among 10^19^ host
    elements drastically modifies the macroscopic properties, the
    possibility of identifying, localizing, and even measuring the
    electronic properties of single atoms becomes of fundamental
    importance in the nanotechnology era. We now have that capability.
    The aberration-corrected scanning transmission electron microscope
    allows not only the imaging of individual atoms inside a crystal,
    but their chemical identification. This remarkable improvement in
    sensitivity reaches the quantum limit of information, the ability to
    probe the electronic environment of a single atom.

-   ***Molecular Cages under Pressure**.* The isolation, removal, and
    entombment of radioactive waste are challenging scientific problems.
    Structural data from high-pressure x-ray powder diffraction has
    demonstrated that cage-like zeolites can potentially separate toxic
    waste from the environment. Using reversible superhydration \-- the
    selective absorption of excess water under pressure into fully
    hydrated zeolites --- the immobilization of commonly occurring
    radioisotopes such as ^90^Sr, ^137^Cs and ^60^Co via a "trap-door
    mechanism" may be realized. By exchanging ions at high pressures,
    the holes of the zeolites will expand due to the excess water
    entering the zeolite cages. After pressure release these holes
    contract again, essentially closing the trap door and sealing the
    waste inside the zeolite for good.

-   ***Biocompatible Lasers for Ultrasensitive Detection**.* A highly
    sensitive quantum optics device using a biocompatible semiconductor
    laser microcavity has been devised that can analyze and characterize
    spore simulants. This device is based on recent advances in the
    surface chemistry of semiconductors and the concept of quantum
    squeezing of light emitted through a spore flowing at high speed in
    the laser's microcavity. This light squeezing enables even tiny
    spores to generate a very large signal which, when analyzed, yields
    critical biological information including the spore's protein coat
    morphology, shape, intracellular granularity, protein density, and
    uniformity. This field-deployable biolaser should be able to
    identify different types of spores (for example, anthrax) within a
    large population of harmless spores rapidly and effectively.

-   ***Electrocatalyst Design for Fuel Cells**.* Electrocatalytic fuel
    cells at ambient temperature require materials with high catalytic
    activity and high tolerance to poisons such as carbon monoxide and
    sulfur. The use of alloys presents inherent limitations including a
    random distribution of the constituent elements and their propensity
    to segregate. The use of ordered intermetallics provides stable
    ordered phases. Based on studies of model systems, it is predicted
    that the ordered intermetallic bismuth-platinum (BiPt) should
    exhibit high catalytic activity and greatly reduced poisoning from
    carbon monoxide. These predictions, based on electronic and
    geometric effects, respectively, were borne out by experiments. BiPt
    catalyzes the oxidation of formic acid is a better material than
    pure platinum in some ways; moreover, it exhibits catalytic currents
    that are about 30 times those on platinum and is virtually immune to
    carbon monoxide poisoning. Although the focus has been on anode
    materials, this new design paradigm has clear implications in the
    design of cathodes as well as reformer catalysts and could usher a
    new era in fuel cell R&D.

    **Chemical Sciences, Geosciences, and Energy Biosciences
    Subprogram**

-   ***Emergence from the Primordial Soup**.* Fifty years ago, Miller
    and Urey (Science, 1953) showed that simple inorganic molecules
    presumed present in the early earth atmosphere could yield amino
    acids after exposure to an electric discharge. Subsequent models of
    the chemical origin of life were complicated by the requirement to
    explain the asymmetric (chiral) nature of DNA and its components.
    Both of these elements are addressed in recent work using advanced
    mass spectrometric tools to study amino acid aggregation and
    reaction products in the gas phase. The simple amino acid serine is
    the commonly accepted product of formaldehyde and glycine, both
    known to exist in interstellar space. Using sonic-spray ionization
    with mass spectrometric detection, researchers have shown that
    certain, especially stable, clusters of serine are homochiral, that
    is, exclusively one of the possible symmetries. Furthermore, in
    reactions of the cluster with other important biological molecules,
    the asymmetry is passed on to the reaction products. These
    observations rationalize a model of prebiotic chemistry beginning
    with the assembly of homochiral serine octamers. Following selection
    of a particular homochiral cluster by an unknown asymmetric species,
    reactions with other biologically relevant molecules could pass on
    the asymmetry as further chemical reaction led to the formation of
    chiral, self replicating, life forms.

-   ***Designer Solvents.*** Ionic liquids have already replaced
    volatile, polluting hydrocarbon solvents in some industrial
    processes, and progress is being made in using ionic liquids for
    inherently safe processing of nuclear fuel and radioactive waste. It
    is important to understand how chemical reaction patterns are
    influenced by the unusual environment of ionic liquids. New studies
    have explored fast reactions in ionic liquids by pulse radiolysis
    and have shown that charged species, such as a bare electron
    surrounded by solvent, move more slowly in ionic liquids in
    comparison to neutral species, just the opposite of what is seen in
    normal solvents. Also discovered was a reactive and highly mobile
    form of the electron that exists for only a few trillionths of a
    second in normal solvents but persists thousands of times longer in
    ionic liquids.

-   ***Reactivity within Nanovessels.*** The elusive challenge of
    attaining chemical selectivity close to 100 percent for reactions in
    aqueous solution may eventually be achieved by mimicking Nature's
    most selective catalysts -- enzymes. Researchers are attempting just
    that by synthesizing stable and semi-rigid inorganic cage structures
    that are able to sequester organometallic catalysts in their
    interior. By using the restrictive environment of the nanovessel
    cavity, they have shown reactant-selective organic transformations.
    As a dramatic demonstration of reactant selectivity, they have shown
    that these encapsulated complexes react with aldehydes with rates
    that depend on the size of the molecule, unlike the same complexes
    in solution, which cannot discriminate among aldehydes of different
    length.

-   ***Fundamental Studies of Water.*** It is difficult to identify a
    quantity more fundamental to chemistry than the O--H bond
    dissociation energy of water. Its importance arises from its
    ubiquity, which ranges from elementary reactions to those in complex
    environments such as flame chemistry or atmosphere chemistry. A
    joint experimental/ theoretical study recently revised the value of
    this bond dissociation energy by a small amount. Although a
    relatively small change, the impact of this correction is enormous.
    It will cause changes in the gas-phase acidity of water, several
    proton affinities, all R-OH bond dissociation energies, reaction
    enthalpies of all OH reactions, and heats of formation computed
    relative to H~2~O or OH bond dissociation energies.

-   ***Storing Energy in Dendrimer Tree*s.** Dendrimers are nanoscale
    molecules constructed from branches connected to a central core. If
    a dendrimer is built with an electron acceptor in the core and
    electron donors on the branches, the molecule can capture and
    temporarily store energy from light by moving electrons from the
    branches to the core. Further chemistry can then be used to capture
    the energy permanently before it is dissipated by electron transfer
    back to the branches. A dendrimeric system has been designed that
    functions as an electron antenna, absorbing several photons to
    create a core with a long lifetime. The stored energy can be lost if
    the electron returns to the "hole" it left behind. However, for
    dendrimers with branches long enough to allow their tips to touch,
    the holes are trapped on pairs of molecules at the tips, and the
    charge-separated state lasts for a long period of time.

-   ***Coherent Surface Plasmons in Nanoscale Systems.*** One of the
    great promises of nanotechnology is the localization of phenomena on
    the nanoscale. Theoreticians have recently described the nanoscale
    analog of a laser in which coherent optical-frequency radiation
    fields are confined and amplified in nanosystems. They show that
    quantum generation of surface plasmons for a nanoscale v-shaped
    metal or semiconductor pattern can lead to stimulated emission and
    gain for certain highly localized plasmon modes. Such a device has
    been christened a SPASER, for Surface Plasmon Amplification by
    Stimulated Emission of Radiation. If realized, the SPASER has
    enormous potential applications in nanotechnology, including optical
    detection and information processing.

-   ***Triple-Action Catalytic Polymerization.*** Catalysts that involve
    multiple functions working in concert at the molecular level offer
    dramatic advantages over single-function catalysts by reducing
    intermediate separation steps and achieving unusual reaction
    selectivity by controlling the competitive interplay of catalytic
    sites and the various molecular species present in the solution.
    Triple functions were synthesized on a complex catalytic compound
    that is active for ethylene polymerization. The terfunctional
    catalyst produces branched polyethylene with regular structures that
    cannot be obtained with a single catalyst or a pair of catalysts
    working in tandem. The extent and type of branching exhibited by the
    polymers, and therefore the chemical, mechanical, and optical
    properties of those materials, can be controlled by adjusting the
    ratios of the different functionalities.

-   ***Multidimensional Chemical Analysis of Attomole Sample.*** Modern
    applications of chemical analysis, ranging from pollution studies to
    homeland security, increasingly require the ability to interrogate
    extremely small sample sizes. These mass-limited situations might
    arise because the sample is incredibly expensive, unusually toxic
    (biothreat agents), or inherently difficult to obtain in large
    quantities (intracellular signaling molecules). Conventional
    instrumentation is challenged, because their requirement for large
    sample volumes leads to extremely diluted samples. Researchers are
    developing solutions to this conundrum by exploiting the special
    electrokinetic flow properties of tiny cylindrical capillaries to
    create multilayer chemical instrumentation capable of addressing
    samples as small as 1,000,000 molecules and below. Because the
    capillaries are less than 100 nanometers in diameter, they can
    control fluid flow among layers of microchannels, thereby making it
    possible to sequentially link separate chemical manipulations. For
    example, scientists recently demonstrated the use of a nanocapillary
    molecular gate to detect and capture a 100 attomole (10^-16^ moles)
    band from a chip-based electrophoretic separation, establishing a
    new low for preparative chromatography of mass-limited samples.

-   ***DNA Transport through a Single Carbon Nanotube.*** Carbon
    nanotubes have been proposed as useful media for a variety of
    applications such as hydrogen storage, chemical separation, and
    ultrasensitive sensors. A common research theme among these
    applications is the need to understand mass transport through such
    nanoporous materials. In a dramatic demonstration of its separations
    capability, a single, multiwalled carbon nanotube has been
    immobilized within an electrophoretic membrane test chamber and the
    passage of single DNA molecules has been monitored by fluorescence
    microscopy. Individual DNA molecules having a diameter smaller than
    the nanotube's opening were observed to readily pass through,
    whereas larger DNA molecules exhibited behavior consistent with
    trapping and hindered passage. Because of the simple structure of
    the nanotubes, modeling can yield insight into the mass transport
    properties of its very small pores.

-   ***Actinide Supramolecular Chemistry: Giant Rings for Heaviest
    Atoms**.* Supramolecular chemistry is the controlled formation of
    large molecular aggregates from smaller subunits. The formation is
    controlled in order to achieve or optimize specific chemical
    properties. Actinide ions, the largest metal ions, have unique
    electrons configurations and represent materials that can be
    extremely useful or extremely dangerous. Supramolecular assemblies
    called helicates have been created where six thorium ions are
    encapsulated in a "box" (cluster) that self-assembles from eight
    smaller assemblies, which will now be investigated for their ability
    to remove toxic ions such as the actinides from the body.

-   ***Targeted Recognition of Actinide Ions.*** Fundamental research on
    the selective complexation of specific ions of radioactive elements
    with disk-like complexants has led to simple and sensitive detection
    of these ions. Several classes of disk-like complexants create
    strong bonds between actinide ions, all of which are radioactive,
    and nitrogen atoms in the cages. These bonds cause transitions in
    electronic and vibrational spectra that result in visible color
    changes that occur only when specific actinide ions, in particular
    ions of neptunium and plutonium, are present. These colored
    complexes are important because of the changes they cause in
    electronic and vibrational structure and because they represent
    opportunities for detection of potentially hazardous radioactive
    ions that could be released into the environment -- or to reassure
    first-line responders and the public that such species have not been
    released.

-   ***Life Cycle of a Water Molecule on an Electrode.*** Technological
    progress towards a future hydrogen economy relies on understanding
    molecular-level phenomena governing conversion hydrogen formation at
    the electrodes in electrolyzers and fuel cells. Ruthenium dioxide is
    unsurpassed at enhancing catalytic activities in room-temperature
    fuel cell anodes, and it is a very promising electrocatalyst. Using
    synchrotron x-ray studies, fascinating sequential rearrangements of
    surface water molecules were discovered, evolving from a loose
    hydrogen-bonded water layer, to a hydroxide layer, and to a dense
    form of water, which exist on the ruthenium dioxide surface at
    different applied potentials. These interfacial forms of water may
    be the intermediates long suspected to be responsible for promoting
    oxidation of hydrogen and methanol in the fuel-cell environment as
    well as promoting the oxygen-evolution reaction. These previously
    unavailable molecular-level details of the energy-conversion
    processes provide scientific impetus for a more rational design of
    high performance electrocatalysts. This first-of-its-kind study was
    possible because of the unprecedented level of sensitivity afforded
    by the high brilliance of today's synchrotron radiation light
    sources.

-   ***Identification and Structural Determination of a Novel Protein
    Motif.*** The protein machinery within a biological cell is
    manufactured via a complex assembly line that stretches from
    decoding DNA into RNA and translating the message into a polypeptide
    chain. Subsequent assembly into larger complexes and covalent
    linkage of the peptide chain with other carbohydrate or lipid
    components may also occur to provide additional chemical reactivity
    or specificity. The photosynthetic machinery that captures light
    energy and turns it into chemical energy is assembled in just such a
    fashion, with both large and small subunits of the carbon-fixing
    enzyme, Rubisco, undergoing methylation on lysine residues. A novel
    protein motif called the SET domain that carries out the methylation
    of Rubisco has been identified and its structure determined. The SET
    domain has been found in many other enzymes in a variety of
    biological contexts ranging from enzyme substrate recognition to
    scaffolding and stabilizing DNA. The common function of recognizing
    a molecular structure for subsequent covalent modification may lead
    to a common code for deciphering regulatory mechanisms of catalysis
    and molecular recognition.

-   ***First measurement of how much energy is required to insert a
    single new protein into a chloroplast.*** The presence of internal
    organelles within the plant cell poses numerous challenges for the
    coordinated synthesis and trafficking of new proteins, which often
    must be synthesized in one part of the cell and directed to another
    sub-cellular compartment. The latter process necessitates the
    movement of the new protein across one or more membranes. Plant
    chloroplasts represent a unique opportunity to study the energetics
    of a mixed transport system that incorporates the cellular
    challenges of both eukaryotes and microbes. The energetic cost of
    this process is a fundamental unanswered question in plant biology,
    since the majority of photosynthetic apparatus proteins are
    continuously synthesized and imported into the chloroplast, then
    rapidly degraded. DOE/BES support has led to the first measurement
    of how much energy is required to insert a single new protein---an
    astonishingly high proton flux that is equivalent to the energy
    stored within 10,000 ATP molecules! Thus approximately 3% of the
    total energy output of the chloroplast from photosynthesis is
    devoted to maintaining the photosynthetic machinery. This knowledge
    provides the foundation for future strategies for more efficient
    light-harvesting applications for renewable energy.

**Selected FY 2003 Facility Accomplishments**

-   **The Advanced Light Source (ALS)**

    *Record Low Vertical Emittance Demonstrated.* The emittance is a key
    parameter that describes the circulating particle beam in a storage
    ring. Accelerator scientists have reduced the ALS vertical emittance
    to 5 picometer-radians during accelerator physics experiments. This
    is the lowest emittance value ever realized in any storage ring.
    While this emittance is a factor of 20 lower than the value normally
    used in ALS operation for users, it will be especially important for
    future spectroscopy studies in which the highest possible resolution
    is important.

    *Femtosecond R&D Program Launched.* The study of ultrafast dynamical
    processes on the time scale of fundamental processes, such as a
    molecular vibration, is one of the most active areas of modern
    science. An ALS R&D program was initiated that aims to produce
    ultrafast x-ray pulses by means of a technique known as
    electron-beam slicing. To generate x-rays from soft to hard x-ray
    energies with the maximum intensity the first, narrow-gap, in-vacuum
    undulator will be installed in the ALS.

    *Beamline Devoted to Study of Soft X-Ray Coherent Science.*
    Exploitation of the coherence of undulator light has not kept pace
    with that of other properties, such as brightness. To address this
    issue at the ALS, a branchline dedicated to coherence has been added
    to an existing undulator beamline that will produce microwatts of
    tunable coherent soft x rays. This new capability will allow users
    to carry out a wide range of experiments in both scattering and
    fundamental optics.

    *Next-Generation Detector for Synchrotron Radiation Developed.* The
    brightness of third-generation synchrotron radiation sources often
    generates huge signal rates that overwhelm the capabilities of
    existing detector systems. Often, the detector saturation problem
    both prevents the fullest utilization of the synchrotron light and
    limits the realization of certain new types of experiments. To
    overcome this bottleneck, the ALS has developed and successfully
    tested a high speed (more than 1 GHz), next-generation detector
    based on high-energy physics technology.

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-   **The Advanced Photon Source (APS)**

    *A Bull's Eye for Storage Ring Beam Orbit Stability.* Stable x-ray
    beams are critical for all users of x-ray facilities, particularly
    those users who microfocus x-rays onto small samples. X-ray
    beam-position monitors developed for the APS insertion device
    beamlines are providing beam stability that is now equivalent to
    firing a stream of bullets through the bull's eye of a target from
    several miles away.

    *New Information from APS Could Lead to Improved Data Storage.* A
    surface twisted magnetic state predicted 15 years ago has, for the
    first time, been confirmed using a new experimental technique at the
    Basic Energy Sciences-funded X-ray Operation and Research sector 4
    at the APS. Twisted magnetic states of materials have important
    ramifications for applications in the development of improved
    magnetic memory.

    *EPICS Collaboration Helps APS and the World.* EPICS (Experimental
    Physics and Industrial Control System) software developed at two
    U.S. Department of Energy national laboratories is being used
    worldwide to control complex mechanical systems, from accelerators
    that reveal the nature of subatomic particles, to observatory
    telescopes that view distant galaxies, to industrial control
    processes such as semiconductor wafer manufacturing.

    *Optics Capabilities at the APS Enable New Dynamical Studies of
    Liquids and Solids.* Inelastic x-ray scattering (IXS) is a
    synchrotron x-ray tool that opens new vistas for the study of
    high-temperature materials. The x-ray optics capabilities of the APS
    have reached a level that makes possible implementation of an IXS
    spectrometer with exceptional resolving power.

    *A Breath of Fresh Air for Insect Physiology.* A technique that
    couples phase-enhanced x-ray imaging to the intensity of APS x-ray
    beams has revealed a previously unknown insect breathing mechanism.
    Further development of this technique could have important
    implications for human health care and afford the potential for a
    wide variety of other materials-related applications, including
    detecting and studying cracks, voids, and other boundaries inside
    optically opaque structures; studying fluid flow in rocks and soils
    for oil exploration and recovery; and characterizing advanced
    materials, such as ceramics and fiber composites.

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-   **The National Synchrotron Light Source (NSLS)**

    *High Gain Harmonic Generation (HGHG) FEL Reaches Saturation in
    Ultraviolet.* The NSLS is pioneering the development of laser seeded
    Free Electron Lasers (FEL). The HGHG FEL makes uses of a Ti-Sapphire
    seed laser to produce fully coherent 266 nm light. This marks the
    first HGHG FEL to successfully reach saturation in the ultraviolet
    regime and thereby obtaining sub picosecond pulses with energy in
    excess of 100 microjoules.

    *New Powder and Single Crystal Diffraction Beamline Completed.* A
    new bending magnet beamline, X6B, has been completed. The beamline
    was constructed to meet the increasing demand of nanoscience users
    for powder and single crystal x-ray diffraction. The beamline
    consists of a Si(111) monochromator, tunable from 5 keV to 20 keV,
    and a double focusing mirror. The beamline is designed to
    perform (a) time-resolved powder diffraction, (b) combined x-ray
    spectroscopy and x-ray diffraction, (c) single crystal diffraction,
    and (d) measurement of electron density of excited states.

    *Superconducting Wiggler Beamline Upgraded.* The X17 superconducting
    wiggler beamline is the only high-energy x-ray insertion device at
    the NSLS. It serves a large and very productive earth science and
    high-pressure users community. In FY 2003, two new experimental
    hutches were constructed so that a materials science instrument, a
    large volume press instrument and a diamond anvil cell instrument
    will each have a dedicated experimental hutch. All three programs
    will be able to operate simultaneously, thus significantly
    increasing the amount of beam time available to these user
    communities.

    *Low-Energy X-Ray Beamline Upgraded.* The low-energy x-ray region is
    important because it covers the K absorption edges of Si, S, P, Cl,
    and L edges of 4d transition metals. X-ray spectroscopy and x-ray
    resonant scattering in this energy range are valuable tools in
    catalysis, environmental science, magnetism and bio-materials. A new
    monochromator was designed and installed in FY 2003 to improve the
    cooling of the monochromator crystals in X19A beamline. The new
    design has led to better energy and intensity stability of the
    beamline.

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-   **The Stanford Synchrotron Radiation Laboratory (SSRL)**

    *First Beam from the Sub-Picosecond Pulse Source (SPPS) is
    Achieved.* Ultrafast pulses of x-rays are key tools for probing the
    electronic and structural changes in materials during fast chemical
    reactions and phase changes. To this end, the SPPS was installed in
    the SLAC Final Focus Test Beam Facility, which generates pulses of
    8-10 keV x-rays with 10^7^ photons/pulse at a pulse rate of 10
    pulses per second. The peak brightness of these x-ray pulses exceeds
    that of any existing x-ray source. The SPPS is planned to operate
    3-4 months per year through 2005, when it will be displaced by the
    construction of the Linac Coherent Light Source, a much more intense
    source of short x-ray pulses.

    *SSRL's Final Run with SPEAR2 Ends on a Perfect Note.* SSRL's most
    recent experimental run prior to the decommissioning of SPEAR2 ended
    very successfully with SPEAR delivery of scheduled beam time to
    users at the 100% mark during the last week of operations. Even
    though the FY2003 run was shortened by about 4 months due to the
    beginning of the SPEAR3 installation, a total of 813 users came to
    SSRL during the run to conduct experiments on 32 stations. The up
    time average for the entire FY2003 run was 96.8%.

    *SPEAR3 Installation Program Proceeding on Schedule.* The SPEAR3
    Installation Program began on schedule on March 31, 2003. The
    Installation Program involves three phases: demolition of SPEAR2,
    modification of the facilities to meet SPEAR3 needs, and finally the
    actual installation of SPEAR3 technical systems and components. Each
    phase is a complex procedure that is planned in great detail with
    overall completion by the end of October 2003.

    *New Experimental Station Developed on BL11.* A new experimental
    station that will be used for both materials scattering and
    macromolecular crystallography has been commissioned on BL11. This
    new station will help relieve the significant over subscription on
    BL7-2 for users performing x-ray structural studies of thin films as
    well as provide for single- or multi-wavelength anomalous dispersion
    (SAD and MAD) experiments to be carried out at the Se edge for
    macromolecular crystallography applications.

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-   **The Intense Pulsed Neutron Source (IPNS)**

    *Upgrades of IPNS Instruments Continue.* IPNS continues to make
    major instrument upgrades and source improvements to maintain world
    class science capabilities for U.S. users: 1) an upgrade project for
    a powder diffractometer, GPPD, has been completed putting the
    instrument on a par with the fastest powder instruments in the
    world; 2) installation of a guide on QENS, a quasi-elastic
    spectrometer boosted flux on sample by a factor of five; 3)
    redesigning the moderator/reflector assembly resulted in a gain of
    60% neutrons-on-sample for small angle scattering applications.

    *Outstanding Operations at IPNS Continues.* For the sixth
    consecutive year, the IPNS has exceeded its goal of offering at
    least 95% reliable operations, achieving a figure of 97% in FY 2002.
    This reliability assures users that experiments can be performed as
    planned and offers additional evidence that pulsed neutron sources
    can be run in a reliable manner.

    *IPNS Hosts the National Neutron and X-Ray Scattering School.*
    During the two-week period of August 10-24, 2003, Argonne National
    Laboratory again hosted the National School on Neutron and X-Ray
    Scattering. The school continues to attract outstanding graduate
    students and post-doctoral appointees with 143 applications for the
    60 positions available in 2003.

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-   **The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
    Neutron Science Center (LANSCE)**

    *First Results with the 11-T Magnet at Lujan Center.* The newly
    commissioned 11-T superconducting magnet provided Lujan Center users
    with the first results of an intensity image (reflection) of neutron
    data collected from an antiferromagnetic material on the new Asterix
    instrument. Significantly, the mass of material contributing to the
    reflection is only about 100 micrograms. Moreover, exceedingly good
    thermal stability was achieved during the measurements.

    *Upgraded NPDF Produces 300 Data Sets.* The Neutron Powder
    Diffractometer (NPDF) opened its shutter for the first time and
    produced over 300 experimental data sets during the run cycle.
    Promising results obtained during the run cycle not only put NPDF at
    the cutting edge of local-structure determination but also served as
    a development platform for a new structure-analysis tool based on
    pair-distribution functions in disordered and nanostructured
    materials.

    *Upgrades to SPEAR Improve Reflectivity Measurements.* Upgrades to
    SPEAR have simplified the operation of the instrument and provided
    more precise and reproducible reflectivity measurements. SPEAR is a
    time-of-flight neutron spectrometer ideally suited to study thin
    organic and inorganic layers in a variety of environments. A recent
    experiment on SPEAR provided fundamental information about the
    stability of model biomembranes in the presence of large electric
    fields.

    *Upgrades to LQD Enables More Sophisticated Small-Angle Scattering
    Experiments.* Small-angle scattering has been improved at the Lujan
    Center to keep apace with the significantly increased cold-neutron
    flux available to LQD (Low-Q Diffractometer), which has been
    increased by approximately a factor of five. These upgrades will
    allow more measurements, higher-quality data, and the ability to
    perform more sophisticated experiments.

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-   **The High Flux Isotope Reactor (HFIR)**

    *World-Class Triple-Axis Spectrometers Installed at HFIR.* These
    spectrometers, designated HB-1, HB-1A, and HB-3, are exceeding
    performance goals and are equal to the highest intensity instruments
    of their kind in the world. The installation of three additional
    world-class instruments is under way at the HB-2 shielding tunnel,
    which was completed in March 2003. The first of the new instruments
    should be available in early fall 2003 with the other two to follow
    by the end of 2003.

    *Shield Tunnel Installed for the HFIR HB-2 Neutron Beam.* The tunnel
    extends the neutron beam into the beam room and provides full
    neutron beam access to four instruments with individual instrument
    shutters. Installation of the instruments will result in a
    significant increase in the number of experiments that can be
    performed using the HB-2 neutron beam.

    *Construction of the Small Angle Neutron Scattering (SANS) Guide
    Hall Completed.* The high bay guide hall will house the new 40m and
    35m SANS instruments and supporting lab space. It will provide a
    research environment away from the reactor building that will be
    used by numerous facility users for physical and biological material
    studies.

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-   **The Combustion Research Facility (CRF)**

    *New Capability Developed for Three-Dimensional Measurements in
    Turbulent Flames.* Lasers and digital camera systems for imaging of
    laser-induced fluorescence in two intersecting planes were added to
    existing systems for line-imaging measurements of temperature and
    major species in turbulent flames. The combination yields
    information on the magnitude and effects of three-dimensional scalar
    dissipation, which is a central quantity in combustion theory and
    modeling.

    *Station Established to Generate Periodically Poled Lithium Niobate
    (PPLN).* A station has been designed and built to pole lithium
    niobate at the CRF. PPLN is a quasi-phase-matched crystal that is
    significantly more efficient and tunable than conventional crystals.
    Recent major advances in nonlinear optical materials have opened up
    many new possibilities for chemical sensing. In particular, the
    development of PPLN has sparked the advent of broadly tunable,
    compact, highly efficient infrared laser sources. This technology
    could be applied to problems such as medical monitoring or transient
    molecule detection.

**Selected FY 2002 Scientific Highlights/Accomplishments\
\
Materials Sciences and Engineering Subprogram**

-   ***Giant Magnetoresistance (GMR).*** GMR is revolutionizing the
    magnetic recording and data storage industry by enabling major
    increases in data density and ease of read/write processes. GMR is
    the term applied to layered magnetic systems that undergo very large
    changes in resistance in the presence of a magnetic field. The
    origin of GMR and its relationship to layered structure is unknown.
    New experiments in which the GMR is measured with current flowing
    perpendicular to the layer interfaces have yielded insight into the
    factors underlying the effect. Measurements of the GMR in samples
    with quantitatively determined interfacial structure, characterized
    by microscopy and x-ray scattering, have shown a direct relationship
    between the GMR and the interfacial roughness. Since most GMR-based
    devices rely on the magnitude of the effect, these results provide
    guidance for their optimization by interfacial roughness tailoring.

-   ***Multifunctional Materials.*** For the first time, organic
    materials that exhibit bistability simultaneously in three channels
    -- magnetic, optical, and electrical -- have been produced. The new
    materials have many interesting properties. In one state, they are
    paramagnetic (attracted to a magnetic field), infrared transparent,
    and electrically insulating; in the other state, they are
    diamagnetic (repelled by both poles of a magnet), infrared opaque,
    and electrically conducting. The switching between the two states is
    thermally driven, and a switching temperature just above
    technologically useful room temperature has been achieved. These
    multifunctional materials have the potential for use in new types of
    devices for electronics, computers, and data storage where multiple
    channels are used for reading, writing, and transferring
    information.

-   ***Transparent Electronic Devices.*** Rather than ordinary glass,
    imagine that your window panes at home are a multi-functional wide
    band-gap semiconductor device that might serve as: an energy
    generator, a microprocessor, a detector, and a light modulator. The
    potential of wide-gap semiconductors is enormous, ranging from
    highly efficient solid-state light sources and high-density data
    storage to invisible monitoring devices for national security. The
    key in making this dream a reality is to be able to dope these
    materials with impurities to achieve both the n- and p-type
    mechanisms of electrical conduction. Achieving p-type doping had
    been an insurmountable problem. The root cause was found to be
    twofold: the spontaneous formation of native defects and the
    low-dopant solubility. Suppression of the defect formation was
    achieved by chemical design of the band structure of the
    semiconductor oxides. This approach has led to a family of new
    p-type transparent conducting materials. These studies have
    facilitated the experimental exploration of transparent electronic
    device materials.

-   ***World's Smallest Ultraviolet Nanolasers.*** The world's smallest
    ultraviolet-emitting lasers, based on "nanowires" of zinc oxide,
    have a broad range of potential applications in fields ranging from
    photonics -- the use of light for superfast data processing and
    transmission -- to the so-called "lab on a chip" technology in which
    a microchip equipped with nano-sized light sources and sensors
    performs instant and detailed analyses for chemistry, biology, and
    medical studies. The nanolasers were fabricated using a new
    processing method that can grow arrays of zinc oxide nanowires
    between 70 and 100 nm in diameter with adjustable lengths between 2
    and 10 microns. This development continues the progress in
    semiconductor laser research, providing new materials that extend
    the availability of these versatile and inexpensive light sources
    from the near infrared and red regions of the spectrum into the
    green-blue and near ultraviolet.

-   ***Nanotubes Increase Heat Conduction in Fluids.*** Fluids
    containing 1 percent carbon nanotubes in oil exhibit a 250 percent
    increase in heat conduction. This addition of nanotubes resulted in
    the highest thermal conductivity enhancement ever achieved in a
    liquid -- ten times higher than predicted by existing theories. This
    has required the development of new heat conduction models for
    solid/liquid suspensions. This research could lead to a major
    breakthrough in solid/liquid composites for numerous engineering
    applications, such as coolants for automobiles, air conditioning,
    and supercomputers.

-   ***Molecular Based Spintronic Material.*** For years scientists have
    dreamed of separately controlling the spin and charge of the
    electron to create \"spin electronics\" or spintronics for next
    generation electronic devices. We have advanced one step closer to
    this goal with the fabrication of a new molecular solid integrating
    alternate layers of spin networks with organic metal networks
    through crystal engineering. The close proximity of the spin to the
    metal -- less than one nanometer apart -- promises strong
    communication of spin and charge while allowing each to be
    manipulated separately. The new material is made by relatively
    inexpensively using bottom-up self-assembly as opposed to the
    elaborate and expensive top-down lithography for other semiconductor
    materials.

-   ***Deformation at the Nanoscale.*** Large-scale atomic-level
    simulations reveal how and why conventional dislocation deformation
    processes in materials break down at the nanoscale. Nanostructures
    can experience very high internal stress levels; thus, mechanical
    stability and compliance represent major obstacles in the
    development of nanodevices. The computer simulations demonstrated
    that, as the grain size becomes ever smaller, a material becomes
    harder to deform. However, at a critical size, dislocations no
    longer can exist, because they are comparable to that of the grains
    themselves, and the material suddenly softens again due to the onset
    of novel deformation mechanisms mediated by the grain boundaries
    that contain the grains. This "strongest size" was shown to be a
    function of not only the material itself but also the stress level
    to which it is subjected. These insights will enable the design of
    nanodevices with tailored mechanical performance, capable of
    withstanding the very high stresses under which they often operate.

-   ***Nano-onions.*** Carbon "nano-onions," generated by carbon-arc
    discharge in deionized water, are the latest entry in the fullerene
    family. Their structures resemble onions, with a fullerene at the
    core, surrounded by multiple layers of fullerene-like carbon. The
    arc method produces "nano-onions" with diameters from about 10 to
    150 nm. These "Buckyonions" are easily fractionated on the basis of
    diameter by using flow field-flow fractionation, with small
    particles eluting before larger ones. Characterization of these
    "nano-onions" using electron microscopy and light scattering methods
    could lead to new and novel applications for these materials.

-   ***A Trillion Elements per Square Inch.*** Magnetic storage arrays
    with more than a trillion elements per square inch, ultrahigh
    resolution field emission displays, and high resolution, on-chip
    macromolecular separations devices have been constructed using a
    new, patented technique of self-assembly of polymers. By means of
    routine chemical etching processes, large area arrays of nanopores
    (4-50 nm in diameter) with very high aspect ratios are produced in a
    simple, robust manner. These serve as templates for pattern transfer
    to substrates and as scaffolds to direct surface chemistry or
    electrochemical deposition of metals for the generation of ultrahigh
    density, multilayered nanowire arrays. The simplicity of this
    technique has a broad impact across many disciplines ranging from
    bioactivity to semiconductor devices.

-   ***Molecules of Gases and Water Swim Upstream.*** A theoretical
    analysis has shown that molecules of hydrogen, oxygen, and even
    water can travel across conducting membranes in opposite directions
    from what would normally be expected. An understanding of these
    membranes is important in the development of advanced materials
    systems for energy storage such as fuel cells. The analysis pertains
    to a class of materials called perovskites that can, under some
    circumstances, conduct charge via both individual electrons and
    ionized atoms of hydrogen and oxygen. Individual chemical species
    can move in the \"wrong\" direction from areas where they are at a
    lower concentration to areas of higher concentration. This is
    normally explained by other driving forces that are taken into
    account in a quantity referred to as the chemical potential. In
    mixed-conducting membranes, however, the new analysis shows that
    neutral (uncharged) molecules can even move contrary to the gradient
    in the chemical potential as a result of the simultaneous, coupled
    transport of multiple species.

-   ***Ultra-Sensitive Sensors.*** A new principle for chemical sensors
    with ultra-high sensitivity has been developed and successfully
    demonstrated based on computer simulations of the structure and
    properties of particle composites. These sensors are fabricated by
    dispersing electrically conducting magnetic particles into an
    insulating liquid, then organizing the particles into chains with a
    magnetic field while the liquid solidifies by polymerization. These
    materials are referred to as Field-Structured Composites. The
    particle chains conduct electricity quite well. When exposed to
    certain chemical vapors, the polymer absorbs the chemicals and
    swells. The chains are stretched ever so slightly to create gaps
    between the particles, resulting in conductivity decreases of ten
    billion or more. The unprecedented magnitude of this effect makes
    these materials sensitive to even trace amounts of vapors.
    Inexpensive, portable devices for chemical identification can be
    achieved by making an array of sensors, each of which is fabricated
    with a polymer having unique chemical affinities, so that any single
    vapor leaves an identifying signature on the array.

-   ***New Analysis Method Enables Prediction of Dendritic Pattern
    Formation.*** Just as water freezes into the elaborate patterns of
    snowflakes, so do metals form highly branched patterns called
    dendrites. These dendrites control many aspects of the processing
    and microstructure that determine alloy properties and hence our
    ability to use materials. Dendrite patterns are controlled by minute
    variations of the interface between the material and its melt. While
    simulations have modeled the atomic processes that occur during
    solidification, they have proven inadequate to extract the more
    subtle information about the anisotropy. An entirely new method to
    extract the anisotropy of energy and mobility from supercomputer
    simulations has been devised. The critical step was the
    identification of a related quantity that can be calculated with
    sufficient precision and then used to simulate dendritic growth.
    Additional supercomputer simulations have exploited this new
    information to predict the precise nature of dendritic pattern
    formation in a range of materials from silicon to nickel.

-   ***Superconductors Show Their Stripes.*** Like tigers and zebras,
    superconductors are distinguished by their stripes. Some physicists
    believe that electricity runs without resistance along "stripes" of
    electric charge in these materials. Stripes have now been observed
    for the first time the most widely studied of the cuprate
    high-temperature superconductors. The material consists of planes of
    copper and oxygen atoms located in a square pattern. Some of the
    electrons are missing in these planes leaving positively charged
    holes that pair together to produce superconductivity. In a standard
    superconductor, these pairs travel through the material without
    hindrance producing the perfect conductivity inherent to a
    superconductor. However, in the cuprate materials, the copper atoms
    have a magnetic moment that makes conductivity in the planes
    difficult. Recent neutron scattering measurements made at the High
    Flux Isotope Reactor show that the holes form lines or stripes in
    the superconductor in which there are no magnetic moments. The holes
    can thus move along the stripe in an unimpeded manner.

-   ***Neutron Instrumentation for Nanoscience.*** Nanoscience requires
    the study of structures ranging from a few nanometers to a few
    microns. A new neutron scattering technique for study of materials
    in this size range has been developed. The method uses the fact that
    the spin of the neutron has unique behavior in a magnetic field \--
    the spin precesses like a top in a magnetic field so that the total
    rotation angle of the spin depends on the time the neutron spends in
    the magnetic field. By appropriately designing the magnetic fields,
    the rotation angle can be made to depend on the direction of
    travel of the neutron with respect to some fixed spatial direction,
    effectively \"coding\" the trajectory angle into the value of the
    neutrons spin. This technique can easily be implemented and could be
    perfected in time to impact early measurements at the Spallation
    Neutron Source. 

**Chemical Sciences, Geosciences, and Energy Biosciences Subprogram**

-   ***Catalytic Chemistry of Gold Nanoparticles**.* Gold spheres of 2.7
    nm diameter supported on titanium oxide are able to oxidize carbon
    monoxide, and spheres of 2.4 nm diameter are able to activate oxygen
    from air and insert it into propene readily and very selectively.
    Yet bulk gold metal is inert, and particles of slightly smaller or
    larger diameter than those cited are also unreactive or unselective.
    Using a variety of spectroscopic and chemisorption techniques,
    atomic-resolution microscopy, and theoretical electronic structure
    calculations, it was shown that decreasing metal particle size
    provokes changes in the electronic structures of gold and titanium
    oxide such that the particles are able to acquire a partial charge.
    Those variations are shown to decrease the binding energy of gold on
    titanium oxide (and thus alter the morphology of the clusters), as
    well as increase the binding energy of reactants such as oxygen,
    carbon monoxide, and propene to gold. The results explain why gold
    clusters are active and selective oxidation catalysts and provide a
    semiquantitative framework to predict catalytic reactivity on the
    basis of electronic structure of metal clusters.

-   ***New Nanoporous Catalysts Developed.*** Nanocrystalline materials
    possess unique properties and offer great promise for promoting
    selected physical and chemical processes. Crystalline films of
    magnesium oxide that consist of tilted arrays of filaments attached
    to a flat substrate have been synthesized by impinging a magnesium
    atom beam in an oxygen background toward a surface off-normal by 70°
    to 85°. The individual filaments are thermally stable, highly
    ordered and porous, and contain enormous numbers of binding sites in
    comparison to a magnesium oxide flat surface deposited on a
    substrate. The high surface area (\~1,000 m^2^/g) and high density
    of binding sites potentially render these nanoporous materials
    extraordinary catalysts.

-   ***Multidimensional Catalyst Arrays**.* Studies of the affects of
    particle spacing on the reactivity of catalysts has been hampered by
    the inability to produce uniform nanoparticles that are regularly
    distributed in a supporting matrix. Recent work shows that two- and
    three-dimensional arrays of platinum nanoparticles are achievable.
    Two-dimensional arrays of platinum supported on 4-inch silicon
    wafers were produced using electron beam lithography and spacer
    photolithography. The latter technique permits variation of particle
    size from 600 nm to 10 nm. More recently, three-dimensional arrays
    of 2-5 nm platinum nanoparticles of vary narrow size distribution
    were prepared, and the resulting x-ray and electron diffraction
    patterns are typical of crystallinity, hence regularity. The results
    significantly enhance enable the production of designer catalysts
    and will answer fundamental questions in catalysis.

-   ***Nanostructured Anodes**.* There is considerable interest in
    tin/lithium anodes for high-energy electrochemical storage systems
    because, in principle, they can deliver substantially more storage
    capacity than carbon based lithium ion batteries. However, the
    tin-based anode functions by reversibly alloying lithium into the
    tin, and a very large volume expansion occurs when lithium is
    alloyed (as much as 300 percent). As a result, the tin based anode
    system typically has poor cycle life because the volume expansion
    and contraction during cycling causes the anode to self-destruct.
    New research has shown that nanostructured tin/lithium anodes
    prepared via a membrane template method do not suffer from this loss
    of cycle life, even after 1,400 charge discharge cycles. The
    nanostructured electrode gives good cycle life because the absolute
    volume change for a nanofiber is correspondingly small and because
    the brush like configuration of nanofibers provides room to
    accommodate the volume expansion.

-   ***Nanometer-Scale Faceting of Metals, a Means to Control
    Reactivity.*** Bimetallic catalysts are providing new insights into
    chemical reactivity. Upon annealing at elevated temperatures, the
    atomically rough, "unstable" surfaces were observed to undergo
    massive reconstruction at the nanometer scale, in some instances
    leading to the formation of surface alloys. These structural
    rearrangements were accompanied by corresponding changes in
    electronic structure, morphology, and catalytic activity.
    Time-dependent, atomically resolved images allowed the measurement
    of the rate of facet growth and of their reconstruction in the
    presence of adsorbates such as sulfur and oxygen. Catalytic activity
    was found to dramatically depend on the composition, structure,
    size, and shape of the facets exposed under reaction conditions.

-   ***Organic Semiconductors.*** Molecular and polymeric semiconductors
    are very important organic compounds that have the potential to
    replace inorganic semiconductors for applications in
    photoelectrochemical and photovoltaic cells for solar energy
    conversion of sunlight to electricity and solar fuels (hydrogen,
    methane, and alcohols). Photoconversion devices based on organic
    semiconductors could be much less expensive and easier to produce
    and process because of the present vast technology available for
    polymer and molecular processing into continuous thin films and
    sheets. Doping the molecular semiconductors to produce the required
    n-type and p-type electrical conductivity to create p-n junctions
    has been problematic as the dopant has not become part of the
    molecular or atomic structure of the compound. Recently, scientists
    successfully doped molecular semiconductors and increased the
    conductivity by five orders of magnitude.

-   ***Long-Lived Charge Separation in a Novel Artificial Photosynthetic
    Reaction Center**.* Fullerenes and porphyrins have molecular
    architectures that are ideally suited for photochemical conversion
    and storage of solar energy. Their use as three-dimensional electron
    acceptors holds great promise because of their small reorganization
    energy in electron transfer reactions that can significantly improve
    light-induced charge-separation processes. Recent research indicated
    a 24 percent efficient charge-separation within a molecular tetrad.
    In this linear array, a light harvesting antenna assembly composed
    of two porphyrins and a fullerene-ferrocene photosynthetic
    reaction-center mimic were integrated into a single molecule. The
    380 millisecond lifetime of the spatially-separated and high energy
    radical pair, a product of sequential short-range energy and
    electron transfer reactions, enters a time domain that has never
    been achieved in an artificial reaction center.

-   ***New Technique for Detection of Impact Ionization in
    Semiconductors**.* The thermodynamic conversion efficiency with
    which solar radiant energy can be converted to electricity or to
    stored chemical energy in solar-derived fuels is limited by the
    energy loss of high energy electrons and positive holes created by
    the absorption of high energy solar photons in the photoconversion
    device. The thermodynamic efficiency limit can be more than doubled
    if the high energy photons can be used to create additional
    photogenerated current through a process called impact ionization.
    For the first time, scientists have demonstrated a contactless,
    optical method to detect impact ionization in semiconductors useful
    for solar photoconversion. The method is based on femtosecond
    time-resolved visible pump-infrared probe spectroscopy, and can be
    used to study impact ionization in colloidal semiconductor quantum
    dots where electrical contact to the colloidal particles is not
    possible. Impact ionization in semiconductor quantum dots is
    expected to be greatly enhanced.

-   ***Gas-Phase Chemistry of Actinide Ions.*** The studies of gas-phase
    reactions of ions provide important insights into fundamental
    chemistry. Such studies have previously been limited to transition
    metal ions and to thorium and uranium in the actinide series;
    however, recent work has expanded this approach to the radioactive
    actinides, which cannot easily be studied by conventional
    techniques. One type of reaction that has been particularly
    enlightening involves the metal- or metal-oxide-catalyzed removal of
    hydrogen from alkene hydrocarbons. In these alkene dehydrogenation
    reactions, the neptunium ion is highly reactive, the plutonium ion
    is significantly less reactive, and the americium ion is essentially
    unreactive. This provides clear evidence that the 5f electrons of
    the actinides beyond neptunium are inert in these organometallic
    reactions. Results for the actinide oxide ions have also been
    illuminating, revealing a decrease in reactivity between uranium
    oxide ions and heavier actinide-oxide ions. The role of 5f electrons
    in bonding is central issue in contemporary actinide science, and
    these results provide experimental evidence for a change in the
    bonding nature of the actinide 5f electrons in molecular compounds,
    ranging from being chemically active for the early members of the
    series to being inert for the actinides beyond neptunium.

-   ***Lattice Disorder and f-electrons: Evidence For a New State of
    Matter.*** An important question is the nature of the
    non-superconducting high-temperature superconducting (HTSC) ground
    state from which superconductivity arises. Intermetallic alloys
    containing *f*-electron elements, in which superconductivity is
    absent or is easily suppressed, allow one to explore this question.
    Like HTSCs, *f*-electron intermetallic alloys often behave as
    "non-Fermi liquids" (NFL), so named because they are not consistent
    with Fermi liquid theory, which, until recently, has been the basis
    for explaining the properties of metals. Of specific interest is how
    the atoms surrounding an *f*-electron atom, and how disorder in
    their arrangement, affect magnetic and conducting properties. A
    recent study of these arrangements in the NFL compound UCu~4~Pd
    showed that significant lattice disorder exists. Although such
    disorder can produce NFL behavior within a Fermi liquid model, the
    study showed that there is insufficient disorder for the model to
    match the measured magnetic and conductivity data. That is, the
    system acts as though it is more disordered than it actually is.
    These results strongly imply that lattice disorder precipitates NFL
    behavior in this material, perhaps by amplifying the effect of the
    disorder, and thereby the possibility of a new type of metallic
    ground state.

-   ***Cellulose Biosynthesis.*** The detection and isolation of
    cellulose synthase genes is driving new efforts to understand how
    cellulose acquires its structural characteristics in hopes of
    eventually devising methods of tailoring these characteristics to
    facilitate its use as a renewable resource. Scientists have provided
    a key piece of information in the biochemical dissection of the
    three steps of cellulose synthesis: 1) initiation of the sugar
    chain; 2) adding sugars to the growing chain; and 3) stopping the
    process at a predetermined length. A single copy of a cellulose
    synthase gene was introduced into yeast cells that do not normally
    make cellulose. The result was the formation of a specific
    lipid-sugar compound that serves as a primer for subsequent chain
    growth. Understanding the critical steps in the synthesis of
    cellulose, the most abundant biomolecule, will lead to understanding
    the function of plant cell walls and to engineering modified
    renewable resources.

-   ***Boron in Plant Cell Walls.*** Research has confirmed the role of
    the element boron in the growth and development of plant cell walls.
    Over 90 percent of a plant's boron is associated with the cell wall,
    and boron deficiency leads to stunted plants with malformed and
    brittle leaves. Arabidopsis thaliana mutants with a small change in
    the structure of a major type of cell wall carbohydrate show the
    same characteristics but can be rescued by feeding with excess
    borate. This defect was shown to reduce the plant's ability to bind
    the borate that is needed to form and stabilize the cross-linked
    cell wall. Future mechanistic studies relating borate-carbohydrate
    crosslinking to physiological growth could lead to improved
    strategies for the development and production of renewable biomass
    resources.

-   ***Naturally Occurring Organochlorine Compounds**.* Organochlorine
    molecules are commonly observed in natural soils and have been
    attributed to pollution from manmade sources. Natural organic
    matter, such as humic and fulvic acid, in the shallow subsurface is
    both universal and little understood. It has no fixed stoichiometry
    or structure, cannot be crystallized, and is famously difficult to
    characterize reproducibly. Synchrotron x-ray spectroscopy has been
    used to document changes in the chemical state of chlorine in humic
    materials. This research confirmed the startling conclusion that
    natural organochlorine compounds are common in soil and that there
    is a net transfer of chlorine from inorganic to organic forms with
    common weathering. Abundant catalytic peroxidase facilitates the
    chlorination of natural aromatic organics. These results add strong
    support to the hypothesis that chlorination of organic compounds in
    humic materials is widespread, and may explain the puzzling
    organochlorine concentrations found in otherwise unpolluted
    environments. Accurately understanding natural conditions is
    critical in identifying and taking action to correct man-made
    problems.

-   ***Quantum Degenerate Fermi Gases**.* A new theoretical formulation
    predicts an unusually high critical temperature for the onset of
    superfluidity in a gas of fermionic potassium atoms. This new form
    of quantum matter, which lies between high-temperature
    superconductors and systems that undergo Bose-Einstein condensation
    should soon be achievable experimentally using optical traps. The
    ultimate goal of these experiments is to achieve Cooper pairing, in
    which pairs of fermionic atoms "condense" and occupy the lowest
    quantum states available to the ensemble of trapped atoms. Such an
    accomplishment would permit studies of the underlying mechanism of
    superconductivity.

**Selected FY 2002 Facility Accomplishments**

-   **The Advanced Light Source**

    *Superbend Magnets Extend Synchrotron Spectral Range.* Originally
    designed for highest brightness at longer x-ray wavelengths (soft x
    rays), the ALS has been retrofitted with superconducting bend
    magnets (superbends) that dramatically boost the synchrotron
    radiation intensity at shorter x-ray wavelengths (hard x rays)
    without disrupting the soft x-ray performance of the existing
    beamlines, thereby allowing the ALS to service a broader user
    community.

    *Higher-Order-Mode Dampers Increase Storage Ring Stability.* The
    beam in the ALS storage ring comprises more than 300 discrete
    "bunches" of electrons spaced more or less equally around the ring,
    but interactions between the bunches can cause the beam to become
    unstable. Addition of antennae to the radio-frequency (RF) cavities
    that power the storage ring has substantially improved the
    reliability of the feedback system that combats beam instabilities.

    *A New Radio-Frequency (RF) Feedback Loop Saves Electrical Power and
    Money.* Driven by the soaring costs that came with the California
    energy crisis, staff at the ALS found a way to reduce the
    electricity bill an estimated 11% by implementing a feedback loop
    that reduced power consumption by a klystron power amplifier without
    interfering with other RF-cavity controls.

    *Beamline for Ultrahigh-Resolution Chemical Crystallography
    Commissioned.* Based on a novel miniaturized design that is low-cost
    yet robust and high-performance, the ALS has put into operation a
    new beamline that meets the demands of chemists for a tool to
    rapidly determine the atomic structure of molecules with
    sub-angstrom resolution from solid samples (crystals) as small as a
    few micrometers on a side.

    *An Experimental Station Has Been Designed to Study Magnetic
    Nanostructures.* Consisting of multiple layers of magnetic and
    nonmagnetic materials, each only a few atoms thick, magnetic
    nanostructures are the foundation for advanced magnetic devices. The
    new station at the ALS will allow complete magnetic characterization
    of each layer separately with x rays that are polarized in any
    desired orientation.

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-   **The Advanced Photon Source**

    *Operating in Top-up Mode.* One of the principal operational goals
    has been to run the storage ring in the "constant current" or top-up
    mode. Top-up mode consists of injecting a small amount of charge
    into the storage ring at regular intervals in order to maintain a
    100 mA current. The major benefit of top-up operation is the virtual
    elimination of the beam lifetime (the decay of beam current over
    time) as a factor in further improvements or enhancements of the
    storage ring performance. As an example, the APS can now operate
    efficiently with a lower horizontal emittance, which reduces the
    source size by a factor of two. This reduction in size provides a
    smaller beam spot that can be used to illuminate smaller samples.
    Normally, the decrease in beam lifetime would severely reduce the
    average current available to the users, but with top-up, the
    reduction is non-existent. Top-up operation is now the standard and
    comprises 75 percent of the total operating time of the APS. The APS
    is the first synchrotron facility to have conceived and implemented
    top-up operation.

    *Canted Undulators for Increased Beamline Capacity.* New
    technologies devised to offset the ever-increasing demand for
    beamline access include the "canted undulator" configuration that
    produces two beamlines originating from one point on the ring.

    *New Information on High-Pressure Fuel Sprays.* An x-ray imaging
    technique devised at the Basic Energy Sciences-funded Synchrotron
    Radiation Instrumentation Collaborative Access Team (SRI-CAT) has
    produced unprecedented details of the structure of diesel fuel
    sprays, including the first evidence of supersonic shockwaves in
    sprays as they leave high-pressure fuel injectors. This information
    may lead to improvements in fuel injector-engine emissions and
    efficiency, and earned a 2002 National Laboratory Combustion &
    Emissions Control R&D Award from the Department of Energy.

    *Nanotomography of Integrated Circuit Interconnects.* A
    high-resolution scanning transmission x-ray microscope is providing
    superior 3-D images of the tiny wire interconnects and other
    embedded structures in computer chips without damage to the chips.
    This unique capability makes it possible to more easily identify and
    correct manufacturing problems, and ultimately to build faster,
    smaller, more-efficient, and more-reliable computers.

    *New Lens for Imaging.* An offshoot of APS expertise in x-ray
    beamline instrumentation is the first full-scale crystal-diffraction
    medical-imaging lens. Resolution with this lens is a factor of three
    better than with most current imaging systems. It can be applied to
    small test animals used by the pharmaceutical industry and to
    imaging small parts of the human body. There are also many
    possibilities for nonmedical applications, including examination of
    nuclear fuel elements and location of radioactive material within a
    larger mass.

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-   **The National Synchrotron Light Source**

    *Source Development Laboratory Laser at 400 nm.* The Deep
    Ultra-Violet Free Electron Laser (DUV-FEL) facility marked an
    important milestone, generating laser light at 400 nm by the process
    of Self Amplified Spontaneous Emission (SASE). Achieving intensity
    20,000 times higher than the spontaneous emission, the result showed
    that the electron beam and the undulator system can support lasing
    down to 88 nm, which has strong user interest in the chemical
    physics community.

    *Soft X-ray Undulator Beamline Monochromator Upgrade.* A new
    water-cooled, 6-position interferometrically controlled grating
    chamber was installed at beamline X1B. At present, four new gratings
    (300, 600,1200, and 1600 lines/mm) covering the soft x-ray photon
    energy range from 100eV to 1600eV were outfitted. Resolving power of
    more than 10,000 was achieved. The high energy resolution and
    extended energy range provided by the new monochromator will benefit
    greatly all the experimental programs using the beamline, including
    soft x-ray resonant scattering, emission, and imaging.

    *Ultra-high Vacuum Compatible Soft X-ray Scattering End Station.* A
    novel resonant soft x-ray scattering instrument has become
    operational at the X1B undulator beamline. The instrument combines
    the element and electronic state specificity of soft x-ray
    spectroscopy with x-ray diffraction, which enables the direct
    probing of intrinsic inhomogeneities in strongly correlated electron
    systems and nanoscale magnetic systems. For example, the spatial
    distribution of the doped holes in an epitaxial film of oxygen-doped
    La~2~CuO~4+δ~ was determined recently using this instrument for the
    first time.

    *New End Station for Soft X-ray Coherent Scattering and Imaging.* To
    facilitate nanoscience research, imaging techniques with nanometer
    spatial resolution are needed. A new end station for soft x-ray
    coherent scattering and imaging was designed and constructed. It
    will be used to develop two and three dimensional diffraction
    imaging and tomography with tens of nanometer spatial resolution for
    nano-magnetic, organic, and biological systems

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-   **The Stanford Synchrotron Radiation Laboratory**

    *Accelerator Modeling Toolbox Developed.* An interactive accelerator
    modeling software tool called Accelerator Toolbox has been developed
    that greatly increases productivity and flexibility in interactive
    computer modeling. By making the Accelerator Toolbox available to
    other laboratories via the web, a community of users has grown who
    share code and experience in solving similar accelerator modeling
    problems.

    *High Power X-ray Monochromators Deployed.* X-ray monochromators
    with high-efficiency crystal cooling utilizing liquid nitrogen have
    been designed, fabricated and successfully installed on four
    high-power wiggler beam lines. Their enhanced performance under high
    heat loads has already resulted in significant improvements in the
    stability and throughput of these beam lines. These monochromators
    and others to be implemented will be critical elements in obtaining
    the ultimate performance available from the SPEAR3 accelerator when
    it becomes operational in 2004.

    *Improved Microfocusing System for X-ray Microspectroscopy.*
    Improved tapered metal capillary focusing optics with a 5 micrometer
    focal spot have been successfully integrated into a new system for
    performing microspectroscopy measurements. These developments, which
    included sample scanning capabilities and software for mapping the
    chemical states of the elemental distributions, will ultimately be
    propagated to a number of beam lines to enable microspectroscopy
    research in biology, materials sciences, and environmental sciences.

    *Major Progress in SSRL Beamline Upgrade Program.* A beam line
    upgrade program is underway whose goal is to bring all SSRL beam
    lines to optimal performance with SPEAR3 running at 500 mA.
    Improvements to date include high-stability mirror systems for the
    insertion device-based beam lines, new permanent magnet wigglers, a
    high-resolution soft x-ray monochromator, and new liquid
    nitrogen-cooled two-crystal x-ray monochromators. Some upgrades have
    been completed during the current SPEAR2 operations phase, bringing
    higher performance to the ongoing user research programs.

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-   **The Intense Pulsed Neutron Source**

    *Upgrades of IPNS Instruments.* 1) A project was initiated for the
    development of a large-aperture, magnetic bearings-suspension,
    high-resolution chopper system for the HRMECS and LRMECS chopper
    spectrometers at IPNS. 2) A new scattering chamber for the Small
    Angle Diffractometer is being installed. It will improve the data
    quality and collection rates. 3) Through an IPNS/RIKEN collaboration
    a neutron compound refractive lens based on an assembly of MgF2
    single-crystal prism elements was tested on the POSY II beamline for
    focusing cold neutrons.

    *Operations at IPNS Continues Outstanding.* For the fifth
    consecutive year, IPNS has exceeded its goal of offering at least
    95% reliable operations. This includes delivering the 7 billionth
    pulse to the target. This accomplishment constitutes more pulses
    delivered to target than any other pulsed neutron source in the US.
    In May of 2002, IPNS was designated a Nuclear Historic Landmark by
    the American Nuclear Society.

    *IPNS Hosts the National Neutron and X-Ray Scattering School.*
    During the two-week period of August 12-23, 2002, Argonne National
    Laboratory once again hosted the National School on Neutron and
    X-Ray Scattering. The school continues to attract outstanding
    graduate students and post-doctoral appointees with 160 applications
    for the 60 positions available in 2001.

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-   **The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
    Neutron Science Center**

    *Four Instruments Commissioned.* Four world-class neutron scattering
    instruments completed commissioning and entered the user program.
    These are HIPPO, SMARTS, Protein Crystallography Station, and
    Asterix. New data acquisition systems were completed and installed
    on the new instruments.

    *Pharos Rebuilt.* Inelastic chopper spectrometer Pharos enjoyed
    substantial upgrades, including detectors on the wide-angle bank,
    commissioning of the new vacuum system, new data acquisition
    electronics and computer system, and a new chopper control system.
    Pharos took its first data and accepted its first users since 1997.

    *Designed and Installed New Robust Target System, Mark II.* Using a
    simplified Monte Carlo model, the new target improves cooling in
    Mark I moderator and upper target. A beryllium reflector replaced
    the lead reflector, cooling was simplified, and cadmium decoupling
    in the reflector was removed for more robust operation. The target
    received first beam on July 8, 2002, as scheduled.

    *Completed Basis for Interim Operation for actinide experiments.*
    The new authorization basis enabled over a dozen plutonium and
    uranium studies to be completed and restores an important capability
    to the DOE science complex.

    *New Shutters and Interlocks.* Greater safety, reliability and
    performance were achieved by replacement of Personnel Access Control
    Systems interlocks on all flight paths, replacement of all mercury
    reservoirs and plumbing, and installation of a new fire detection
    system. Two new mechanical shutters and over 300 tons of shielding
    were installed to enable two new flight paths for new instruments.

    *Proton Storage Ring Instability Tamed.* A series of successful
    Proton Storage Ring development tests confirmed that the "e-p
    instability" could be controlled at accumulated charge levels
    approaching 10 μC, well above the goal of 6.7μC.

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-   **The High Flux Isotope Reactor**

    *Major Refurbishment of Reactor Vessel Completed.* The refurbishment
    of the pressure vessel\'s internal components included replacing the
    permanent and semipermanent beryllium reflectors and their support
    structures. This required maintenance was accomplished without
    incident and will support the substantial upgrade in neutron
    scattering research capabilities at HFIR.

    *HFIR Cooling Tower Replaced.* The original 36-year-old wooden
    cooling tower had significant structural degradation, required
    excessive maintenance, and could no longer reliably support reactor
    operations. The more efficient replacement tower will cost less to
    operate and should last for the remaining life of HFIR.

    *New Thermal Neutron Beam Tubes Installed at HFIR.* The new beam
    tubes, which replaced existing tubes that had reached their end of
    life, are capable of providing more neutrons to a greater number of
    scientific instruments.

    *Operational Readiness Review (ORR).* The ORR at HFIR was the first
    to be conducted at any Category 1 DOE facility since the current ORR
    guidance was issued. The ORR included a comprehensive restart plan,
    independent-contractor and DOE reviews, and close coordination with
    DOE headquarters and the site office. Reactor operations were
    resumed on December 18, 2001

    *Facility Improvements Support Neutron Scattering Instrument
    Upgrades.* New monochromator drums were fabricated for the
    triple-axis spectrometers at HB-1, 2, and 3. A shielding tunnel and
    neutron guide were fabricated for HB-2, where a 20-cm-diameter beam
    tube was installed with beryllium inserts to support four beam
    lines. The resulting beam intensity is expected to be three times
    that of the original design for some of the instruments.

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-   **The Combustion Research Facility**

    *Stagnation-flow Reactor Designed to Probe High-temperature
    Chemistry.* Chemically reacting flows at interfaces are an important
    class of processes occurring in combustion, catalysis, thin film
    formation, and materials synthesis. An innovative stagnation-flow
    reactor with access for optical diagnostics and mass spectrometry is
    nearing completion and will provide a valuable tool for probing
    high-temperature chemistry for a broad range of industrially
    relevant processes.

    *Fiber-based Laser Systems Developed.* Fiber lasers and amplifiers
    are unique optical sources that provide many advantages for
    detection of chemical and biological compounds. The CRF has
    established the capability to fabricate them in-house. The facility
    will allow the pursuit of new research in optical diagnostics and
    will help DOE remain at the forefront of this field.

    *New Reactor Allows Investigation of Gasification Processes.* The
    design and facility modifications have been completed for a new
    reactor that will allow unprecedented optical access to pressurized
    combustion and gasification processes. This reactor will give the
    CRF the capability to investigate gas-phase kinetics, materials
    behavior, advanced diagnostic development, and solid and liquid fuel
    combustion chemistry and physics under pressurized conditions.

**Selected FY 2001 Scientific Highlights/Accomplishments**

**Materials Sciences and Engineering Subprogram\
**

***Micro-size Light Emitters for Solid State Lighting Applications.***
Energy savings of tens of billions of dollars per year could be achieved
by replacement of household 100-watt light bulbs by white light emitting
diodes (LED) made by mixing LEDs emitting primary colors. However,
improved LED efficiency is necessary before such replacement becomes
feasible. New research has shown that interconnecting hundreds of
micro-size LEDs to replace larger conventional LEDs can boost the
overall emission efficiency by as much as 60 percent.

***A New Method for Obtaining Crystal Structures Without Large
Crystals.*** High-resolution x-ray diffraction using polycrystalline
samples ("powders") rather than traditional single-crystal samples has
advanced to the point where the structures of complex materials
including oxides, zeolites, and small organic structures can be solved.
Advantages of powder diffraction are that it is not affected by crystal
fracture and polycrystalline samples can be formed over a much wider
range of conditions than large single crystals. Recently, powder
diffraction was demonstrated for large molecules, such as proteins, that
were considered far too complex for powder diffraction experiments. In
addition to the many important applications to materials sciences, this
technique will also be useful in chemistry and biosciences.

***NMR and MRI Outside the Magnet.*** NMR (nuclear magnetic resonance)
imaging and MRI (magnetic resonance imaging) have required large
high-field magnets that impose extremely uniform magnetic fields upon
the sample. In many circumstances, however, it is impractical or
undesirable to place or rotate objects and subjects within the bore of
such a large magnet. A new approach for the recovery of highly resolved
NMR spectra and MRI images of samples in grossly non-uniform magnetic
fields was recently demonstrated. The approach will be useful for the
enhanced study of fluids contained in porous materials, such as deep
underground oil-well logging studies, and is expected to have dramatic
research applications in chemistry, materials sciences, and biomedicine.

***Terabit Arrays (One trillion bits per square inch).*** A 300-fold
increase in magnetic storage density has been achieved using a patented
technique of self-assembly of block copolymers under the influence of a
small voltage. The new technique is simple, robust, and extremely
versatile. The key to this discovery lay in directing the orientation of
nanoscopic, cylindrical domains in thin films of block copolymers. By
coupling this with routine lithographic processes, large area arrays of
nanopores can be easily produced. Electrochemical deposition of metals,
such as cobalt and iron, produces nanowires that exhibit excellent
magnetic properties, key to ultrahigh density magnetic storage. The
nanowires are also being used as field emission devices for displays.

***Observations of Atomic Imperfections.*** A new electron beam
technique has been developed that has measured atomic displacements to a
record accuracy of one-hundredth of the diameter of an atom. Such small
imperfections in atomic packing often determine the properties and
behavior of materials, particularly in nano-structured devices. This
capability has been made possible by a new technique that couples
electron diffraction with imaging technology. The result is a greatly
enhanced capability to map imperfections and their resulting strain
fields in materials ranging from superconductors to multi-layer
semiconductor devices.

***Semiconductor Nanocrystals as "Artificial Leaves."*** Recent
experiments demonstrated that carbon dioxide could be removed from the
atmosphere with semiconductor nanocrystals. These "artificial leaves"
could potentially convert carbon dioxide into useful organic molecules
with major environmental benefits. However, to be practical, the
efficiency must be substantially improved. New theoretical studies have
unraveled the detailed mechanisms involved and identified the key
factors limiting efficiency. Based on this new understanding,
alternative means for improving efficiency were suggested that could
lead to effective implementation of artificial leaves to alleviate
global warming and the depletion of fossil fuels.

***\"Magic\" Values for Nanofilm Thickness.*** A key issue for
nanotechnology is the structural stability of thin films and the devices
made from nanostructures. It was recently demonstrated that nanofilms
are significantly more stable at a few specific values of film
thickness. The origin of this effect arises from the confinement of
electrons within the film leading to electronic states with discrete
energy values, much as atomic electrons are bound to the nucleus at
discreet energy levels. Calculations demonstrated that increased
stability occurred when the number of electrons present in the film
completely filled the set of available states, just as filled electronic
shells make the mobile gases very stable.

***Materials Resistant to Damage from Nuclear Waste.*** The ability to
predict the composition and structure of materials that are resistant to
radiation damage, such as in nuclear waste storage, has been formulated
on a firm scientific basis. Current nuclear storage materials cannot
resist radiation damage for the required thousands of years because
radioactive emissions in a storage material jostle atoms out of their
carefully ordered arrangements. These materials become unstable and
eventually leach into the environment. Computer simulations and
experiments revealed that a special class of complex ceramic oxides
called fluorites is able to resist this fate. The fundamental principle
is rather simple: the configurations of atomic arrangements in these
oxides are relatively disordered to begin with allowing them to tolerate
displaced atoms caused by radiation.

***Brilliant X-Rays Shine Light on Welds**.* Using high-brightness
synchrotron radiation, the details of microstructural changes of welds
were mapped and studied for the first time. This advanced capability
shows how the welding process alters the structure and changes the
properties of metals. Its application is virtually unlimited, since it
can investigate dynamic changes in crystal structure near the melting
point of any metal. Knowledge gained from this award winning work on
titanium and stainless steels is being used to advance and refine
theories and numerical models of welding fundamentals. Dramatic savings
to the U.S. economy would result from better quality, more reliable
welds.

***Micro Lens for Nano Research**.* A silicon lens that is 1/10 the
diameter of a human hair has been fabricated and used to image
microscopic structures with an efficiency 1,000 times better than
existing probes. The combination of high optical efficiency and improved
spatial resolution over a broad range of wavelengths has enabled
measurement of infrared light absorption in single biological cells.
This spectroscopic technique can provide important information on cell
chemical composition, structure, and biological activity.

***Nanofluids**.* Nanofluids (tiny, solid nanoparticles suspended in
fluid) have been created that conduct heat ten times faster than thought
possible, surpassing the fundamental limits of current heat conduction
models for solid/liquid suspensions. These nanofluids are a new,
innovative class of heat transfer fluids and represent a rapidly
emerging field where nanoscale science and thermal engineering meet.
This research could lead to a major breakthrough in making new composite
(solid and liquid) materials with improved thermal properties for
numerous engineering and medical applications to achieve greater energy
efficiency, smaller size and lighter weight, lower operating costs, and
a cleaner environment.

**Chemical Sciences, Geosciences, and Energy Biosciences Subprogram**

***Capturing Molecules in Motion with Synchrotron X-Ray Pulses.***
Photochemical conversion of solar energy depends on light-driven
chemical reactions. Absorption of light ultimately leads to atomic
rearrangements necessary to produce photochemical products. The
intermediate molecular configurations created by absorption of light are
short-lived and their structures are largely unknown. In novel
experiments at the Advanced Photon Source, molecular structures of
laser-generated reaction intermediates in solutions, having lifetimes as
short as 28 billionth of a second, have been obtained. Future
experiments are planned that will allow for capture of intermediate
structures on even shorter time scales. These studies are providing the
fundamental knowledge needed to develop artificial photoconversion
devices.

***Early Precursor Identified in Water Radiolysis**.* Radiolytic
decomposition of water produces hydrogen gas, which is flammable and
potentially explosive. This is of concern in maintenance of
water-moderated nuclear reactors, long-term storage of transuranic
fissile materials containing adsorbed water, and management of
high-level mixed-waste storage tanks. In recent studies on the effects
of ionizing radiation on condensed media, a common precursor to
essentially all hydrogen from irradiated water has been discovered. This
precursor is a solvated electron. External intervention and capture of
this precursor can prevent the generation of hydrogen gas from water.
The reactivity of the precursor with a large number of scavengers has
previously been determined in pulse radiolysis experiments, thus a
priori predictions can be made on the efficiency of the intervention and
prevention of gas generation.

***The World\'s Smallest Laser**.* A team of materials scientists and
chemists has built the world\'s smallest laser - a nanowire nanolaser
1,000 times thinner than a human hair. The device, one of the first to
arise from the field of nanotechnology, can be tuned from blue to deep
ultraviolet wavelengths. Zinc oxide wires only 20 to 150 nanometers in
diameter and 10,000 nanometers long were grown, each wire a single
nanolaser. Discovering how to excite the nanowires with an external
energy source was critical to the success of the project. Ultimately,
the goal is to integrate these nanolasers into electronic circuits for
use in \"lab-on-a-chip\" devices that could contain small laser-analysis
kits or as a solid-state, ultraviolet laser to allow an increase in the
amount of data that can be stored on high-density optical disks.

***Polymerization to Make Plastics.*** The discovery of metallocene
catalysts caused major advances in polymer production (e.g.,
polyethylene, polypropylene), the most widespread of synthetic
materials. The ability to control the orientation of each link of a
polymer chain allows control of crystallinity, density, softening point,
and other important properties. A recent improvement in these catalysts
is the synthesis of bimetallic complexes in which two catalytic centers
and two cocatalytic centers are held in close proximity in solution or
adsorbed on surfaces. By altering the nature of the centers, it is
possible to control rate of reactivity, the degree of chain branching,
and plastic rigidity.

***First Ever Chemistry with Hassium, Element 108**.* Element 108 -
hassium - was discovered in 1984. It does not exist in nature but must
be created one atom at a time by fusing lighter nuclei. Recently, the
first experiments to examine its chemical properties were performed by
an international team (German, Swiss, Russian, Chinese and American
scientists) at the Gesellschaft für Schwerionenforschung (GSI) in
Darmstadt, Germany using novel techniques developed at the Lawrence
Berkeley National Laboratory. Energetic magnesium projectiles bombarded
targets of curium, a rare artificial isotope produced and processed at
Oak Ridge National Laboratory. The hassium atoms formed by impacts
between beam and target reacted with oxygen to form hassium oxide
molecules enabling the study of the properties of this new chemical
compound. The chemistry of man-made and heavy elements, particularly
chemistry impacting environmental insults, is of major interest, and
these experiments are a first step for this element.

***Improved Materials for Fuel Cells**.* Major impediments for the
commercialization of fuel cells include the inability to use hydrogen
fuel containing traces of carbon monoxide and the necessity of using
large amounts of expensive platinum catalysts. A novel
ruthenium/platinum catalyst has been produced through a new preparation
method involving spontaneous deposition of platinum on metallic
ruthenium nanoparticles. The resulting catalyst has a higher carbon
monoxide tolerance than commercial catalysts and uses smaller amounts of
platinum.

***Platinum Encrusted Diamond Films**.* Research on new catalytic
electrodes, e.g., for fuel cells, has shown that synthetic diamond thin
films are excellent supports for catalysts because of their corrosion
resistance. The challenge to produce an electrode is to incorporate
nanometer sized platinum and platinum/ruthenium catalyst particles into
the surface structure of the diamond film. Recently, the ability to
incorporate 10 to 500 nanometer diameter particles into the bulk
structure of the films has been demonstrated. These new surface modified
systems may result in significantly improved catalytic activity and
stability, and could have even broader applications in chemical
synthesis, toxic waste remediation, and chemical and biomedical sensors.

***Complex Flow in the Subsurface**.* Recovery of subsurface fluids,
whether oil and gas or contaminants, requires understanding the way
fluids flow within porous and fractured rocks and soil. This is
particularly complicated when there are multiple fluids
(oil-methane-water; water-carbon dioxide). New experiments combined with
theory and computational modeling have tracked the simultaneous flow of
two fluids in fractured and porous media. Flow paths of both fluids are
significantly longer than under single fluid conditions and transport is
very sensitive to differences in fluid structure.

***Complete Plant Genome of the First Model Plant.*** The first complete
sequencing of a plant genome was completed by an international
consortium of researchers from Europe, Japan and the U.S. The DOE was
one of the supporters of the U.S. effort. The sequencing of the genome
of Arabidopsis will provide the information needed to increase food
production in an energy-efficient and environmentally friendly manner,
provide increased wood and fiber production, and increase the use of
plant materials for energy and the production of petroleum-replacing
chemicals.

**Selected FY 2001 Facility Accomplishments**

The four synchrotron radiation light sources and three BES neutron
scattering facilities served 6,982 users in FY 2001 by delivering a
total of 26,476 operating hours to 204 beam lines at an average of 96.1%
reliability (delivered hours/scheduled hours)[^1]. The High Flux Isotope
Reactor at Oak Ridge National Laboratory did not operate in FY 2001 due
to the installation of upgrades. Statistics for individual facilities
are provided below. In one instance, less time was needed for
maintenance activities than was scheduled, so more time was delivered to
users than planned.

The maximum number of total operating hours for these 7 facilities is
estimated to be about 37,100 hours. Most of the BES facilities already
operate close to the maximum number of hours possible for their
facility. The next priority is to support and maintain beamlines and
instruments at the state-of-the art. For the synchrotron radiation light
sources and the neutron scattering facilities, the number of beamlines
and instruments would need to be increased in order to achieve the full
capacity of each of the facilities. Capacity at the light sources could
increase by nearly a factor of two if all beamlines were fully
instrumented. Capacity at the neutron sources could also increase
substantially by upgrading existing instruments and fabricating new
ones.

**The Advanced Light Source (ALS)** served 1,163 users in FY 2001 by
delivering 5,261 operating hours to 37 beam lines at 96.2% reliability
(delivered hours/scheduled hours). The ALS is supported by the Materials
Sciences and Engineering subprogram.

*A new beamline for x-ray microscopy of polymers.* Owing to its
elemental and chemical specificity, x-ray microscopy is a superior tool
for the study of multicomponent polymers. A scanning x-ray microscope
that is specifically optimized to the demands of polymer research is
being commissioned.

*Ambient-pressure photoemission spectroscopy.* The real world of
chemistry, biology, and environmental science is a world that is
frequently wet, hot, and under atmospheric or higher pressures, whereas
experimental measurements are often best done under vacuum with cold
samples. One step toward bridging the gap is the development of a new
experimental chamber for *in-situ* investigation of samples under
ambient conditions.

*Interferometer controls scanning x-ray microscope.* In scanning
microscopy, it is essential to locate and control the position of the
probe over the sample. A control system developed for a scanning x-ray
microscope is able to position the x-ray beam with nanometer accuracy,
so that features in the sample can be studied at the finest spatial
resolution of the instrument.

*Superbend beamlines developed.* To broaden the spectral range of the
Advanced Light Source to cover shorter wavelengths, superconducting bend
magnets were designed. The first two beamlines will be implemented
sequentially over the next year to serve protein crystallographers and
to provide much needed harder x-ray sources for ALS diffraction studies.

**The Advanced Photon Source (APS)** served 1,989 users in FY 2001 by
delivering 4,788 operating hours to 37 beam lines at 95.8% reliability
(delivered hours/scheduled hours). The APS is supported by the Materials
Sciences and Engineering subprogram.

*Storage ring "top-up operation" becomes routine*. After successful
tests with 25% of the scheduled user-beam time dedicated to top-up
operation, the APS is scheduling the majority of future operations for
top-up mode. During top-up operation, injecting a pulse of electrons
once every two minutes holds the stored current constant to 0.2 percent.
This operating mode delivers a constant heat load on x-ray optics and
various accelerator components, thus improving the x-ray beam stability.
It also allows flexibility in operating modes, which are traditionally
limited by the short lifetime of the stored beam. Top-up operation has
significantly enhanced the research capabilities of the APS.

*Two undulators on a single straight section deliver two independent
x-ray beams to users.* For the first time, a novel concept of spatially
separating the beams from two insertion devices placed on single
straight section was realized. This was accomplished by placing the
undulator axes at a small angle with respect to each other. Successful
implementation of this concept enabled 100% efficient utilization of the
delivered beam.

*Low-emittance lattice developed.* Machine studies have successfully
established operating conditions for the APS storage ring with the
horizontal emittance reduced by approximately a factor of two. This
reduces the horizontal source size and divergence of the x-ray beam and
results in at least a factor of two improvement in the overall
brilliance. Initial user results are encouraging and routine operation
with this mode is scheduled for the near future.

**The National Synchrotron Light Source (NSLS)** served 2,523 users in
FY 2001 by delivering 5,556 operating hours to 86 beam lines at 100.0%
reliability (delivered hours/scheduled hours). The NSLS is supported by
the Materials Sciences and Engineering subprogram.

*Polarization modulation spectroscopy for magnetism research.* A new
high-resolution soft x-ray beamline and a phase sensitive detection
system were completed to take advantage of the fast switching capability
of the Elliptically Polarized Wiggler. The new system provides high
sensitivity and enables magnetic field dependent studies.

*Focusing of high energy x-rays with asymmetric Laue crystals*.
Theoretical prediction and experimental verification of a new concept
for focusing of high energy x-rays was demonstrated. This new design
results in a more than 100 fold increase in the photon flux delivered to
the sample. A new monochromator based on this design was constructed and
implemented at the superconducting wiggler beamline for high pressure
and materials research.

*High magnetic field, far-infrared spectroscopy beamline commissioned.*
A new high magnetic field, far-infrared beamline was commissioned with a
far-infrared spectrometer and 16 Tesla superconducting magnet. Combining
this with a high-field magnet system opens up new opportunities for
measuring electron spin resonance (ESR), cyclotron resonance, and other
magneto-optic effects in solids.

*X-ray optics for microbeam diffraction, elemental mapping, and high
pressure research developed.* A new system for micro-focusing of x-rays
was implemented, achieving a focus of 3 microns (vertical) by 9 microns
(horizontal). The system has been used in the study of bone diseases,
materials under high pressure, and semiconductors.

*High gain harmonic generation (HGHG) free electron laser (FEL) achieves
saturation.* By frequency multiplying and amplifying a seed laser
signal, an HGHG FEL imposes the properties of the laser onto the FEL
output beam. In a demonstration, light at long wavelength was frequently
doubled. Full characterization of the FEL light and its harmonics agreed
with theory and demonstrated the utility of an HGHG FEL for producing
intense coherent light pulses.

**The Stanford Synchrotron Radiation Laboratory (SSRL)** served 907
users in FY 2001 by delivering 4,539 operating hours to 25 beam lines at
94.9% reliability (delivered hours/scheduled hours). The SSRL is
supported by Materials Sciences and Engineering subprogram.

*Stanford-Berkeley synchrotron radiation summer school.* The first
Stanford-Berkeley summer school on synchrotron radiation and its
applications was held with 36 students from a diverse range of
scientific fields. The goal was to introduce young scientists to the
fundamental properties of synchrotron radiation and the understanding
and use of several techniques, including spectroscopy, scattering, and
microscopy.

*New actinide facility commissioned.* Synchrotron-based measurements are
a crucial part of chemical and materials research programs involving
radionuclides and radiologic materials. In order not to limit the scope
of experiments that can be performed, a radiologic sample analysis
facility has been integrated into a modern synchrotron beamline. This
combination insures safe handling of actinide and other radiology
materials and also provides state-of-the-art measurement capabilities
that have proven extremely useful in remediation efforts.

*Materials science small angle x-ray scattering beamline facility
completed.* The materials science small and wide-angle x-ray scattering
station is now in full user operation. The integrated beamline and
experimental equipment facility allows for studies of weakly scattering
systems, such as dilute polymer solutions.

*Microfocus optics system for X-ray micro-spectroscopy.* An experimental
apparatus employing tapered metal capillary optics for conducting X-ray
micro-spectroscopy is now in operation. This capability allows X-ray
micro-spectroscopy experiments in the materials, biological, and
environmental sciences.

*Successful 3 GeV injector test.* The SPEAR injector was successfully
run at 3 GeV, proving that it is ready to provide at-energy injection
for SPEAR3. The 3 GeV test came toward the end of the two-year Injector
Upgrade Accelerator Improvement Project, in which power supplies,
magnets, and diagnostics were upgraded to insure reliable 3 GeV
operation. At-energy injection will improve SPEAR3 performance by
providing better fill-to-fill orbit reproducibility and thermal
stability.

*RF waveguide dampers improve beam stability and lifetime.* RF waveguide
dampers were installed in the two radio frequency (RF) waveguides in the
SPEAR storage ring to eliminate high frequency oscillations excited by
the electron beam in the RF cavity/waveguide system. The dampers not
only eliminated the instabilities but they allowed the use of operations
parameters that gave a 20% improvement in the electron beam lifetime.

**The Intense Pulsed Neutron Source (IPNS)** served 240 users in FY 2001
by delivering 3,968 operating hours to 13 beam lines at 102.6%
reliability (delivered hours/scheduled hours). The IPNS is supported by
the Materials Sciences and Engineering subprogram.

*IPNS hosts the national neutron and x-ray scattering school.* In August
2001, Argonne National Laboratory again hosted the two-week National
School on Neutron and X-Ray Scattering. The school continues to attract
outstanding graduate students and post-doctoral appointees with 179
applications for the 60 available positions.

*Upgrade of IPNS instruments.* The High Resolution Medium Energy Chopper
Spectrometer (HRMECS) instrument was completely upgraded and a chopper
was added to the General Purpose Powder Diffractometer (GPPD). The
HRMECS upgrade included the complete overhaul of data collection/control
software and hardware, addition of position-sensitive detectors at low
scattering angles and improved neutron choppers. The T0 chopper on GPPD
blocks high energy neutron from entering the diffractometer.

*Auto-anneal capabilities added to moderator system.* Regular annealing
required for IPNS's unique ultra-cold moderator has been accomplished by
installing a system that automatically anneals the solid methane
moderator every three days. This automation allows for reduced manpower
and improved operation of the IPNS target moderator assembly.

**The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
Neutron Science Center** LANSCE served 122 users in FY 2001 by
delivering 2,364 operating hours to 6 beam lines at 82.0% reliability
(delivered hours/scheduled hours). The Lujan Center is supported by the
Materials Sciences and Engineering subprogram.

*HIPPO diffractometer commissioned.* Following three years of design and
construction, the recently completed HIPPO (High Pressure, Preferred
Orientation) diffractometer took its first neutron-beam-related
diffraction pattern on a sample of nickel on July 7, 2001. The
scientific thrust of this new state-of-the-art spectrometer is the
investigation of dynamic processes in heterogeneous bulk materials in a
variety of environments.

*SMARTS will provide new capabilities in materials research.* SMARTS, a
third generation neutron diffractometer for the study of polycrystalline
materials, received its load frame and furnace, which were successfully
tested onsite during 2001. SMARTS is scheduled to receive first beam in
August 2001, followed by commissioning through the remainder of the
year.

*BES partners on new institutional instruments.* Three institutionally
funded instruments, ASTERIX, PHAROS, and IN500 were supported in part
under the auspices of BES. ASTERIX produces a highly polarized intense
beam of cold neutrons that has a very large cross section and covers a
wide wavelength range while minimizing the fraction of the neutron beam
that is not used. PHAROS, a high-resolution chopper spectrometer, is
designed for low-angle studies. IN500 is a cold neutron time-of-flight
spectrometer, which will offer all the advantageous capabilities of
reactor-based instruments.

*Instrument performance improves with use of new chopper technology.*
All of the Lujan Center\'s new instruments and some of the existing
instruments have enjoyed dramatic improvements in chopper technology in
FY 2001. These performance improvements in two technical areas, timing
reference generators and chopper controls, now enable the accelerator
and all neutron choppers to run as slaves of the master timing
generator. This success in chopper technology has drawn the attention of
several other spallation neutron facilities and has redefined the timing
specifications for the Spallation Neutron Source.

*Upgrades to small-angle scattering instrument.* A new frame-overlap
chopper was procured and installed, which enables the small-angle
scattering instrument, LQD, to make full use of the higher flux it
enjoys from the hydrogen moderator installed over the last two years.
Recent additions to LQD also include a gravity-focusing device, which
compensates for gravitational drop, especially for slow neutrons.

*Upgrades to SPEAR improve instrument performance.* SPEAR (Surface
Profile Analysis Reflectometer) is used for determining chemical density
profiles at solid/solid, solid/liquid, solid/gas, and liquid/gas
interfaces. Upgrades to SPEAR during 2001 included the installation of
shutter hardware to reduce closure time, and additional automation of
flight-path components. For better performance, an evacuated flight
path, and two digital chopper controllers were added. In addition, a new
collimation system, together with improved software, allowed for the
first real-time reflectivity measurements. These upgrades were made to
make the instrument user-friendlier.

**The High Flux Isotope Reactor (HFIR)** served 38 users in FY 2001 by
delivering 8 operating hours for materials irradiation and institutes
that utilize the transplutonium program and medical isotopes. The
reactor was shut down at 8:00 a.m. on October 1, 2000, for the scheduled
replacement of the beryllium reflector and installation of upgrades and
remained shutdown for the remainder of the year. The HFIR is supported
by the Materials Sciences and Engineering subprogram.

*Installation of new components enhances scientific capabilities at
HFIR.* Many of HFIR's internal components have been replaced with new,
upgraded components that will significantly enhance its neutron
scattering research capabilities without diminishing its
isotope-production or material-testing capabilities. Replaced components
include the beryllium reflector, its support structure, and three of the
four neutron beam tubes. Beam intensity for some instruments is expected
to be three times that of the original design.

*Cold Source Project progress.* The moderator vessel has been fabricated
and has passed acceptance pressure tests at room and liquid-nitrogen
temperatures.

*Spectrometers for cold neutron research.* The cold source to be
installed at HFIR will provide long wavelength neutron beams that are
unsurpassed worldwide. Instrumentation has been designed to make optimum
use of the cold neutron beams. Instruments include small angle
spectrometers for measurements on large-scale structures, reflectometers
for the study of surface phenomena, and triple-axis spectrometers for
the determination of low-energy excitations.

*Spectrometers for thermal neutron research.* The larger beam tubes and
new mochromator drums installed at HFIR will permit considerable gains
in intensity for the thermal neutron spectrometers, by as much as a
factor of five.

**The Combustion Research Facility (CRF)** is supported by the Chemical
Sciences, Geosciences, and Energy Biosciences subprogram.

*New capabilities.* The CRF provides a primary interface for the
integration of BES programs with those of DOE\'s Offices of Energy
Efficiency and Renewable Energy and Fossil Energy related to combustion
by collocating basic and applied research at one facility. Three
laboratories were completed. The particle diagnostic laboratory can now
generate flames with controllable fuel and oxidizer feeds to develop a
fundamental understanding of small particle formation from combustion
sources. A time-resolved fourier transform spectrometer for chemical
kinetics and dynamics studies is now available in the kinetics and
mechanisms laboratory. Related to applied research, the investigation of
a novel engine combustion concept is being conducted in the new
homogeneous-charge, compression-ignition engine laboratory.

## Selected FY 2000 Scientific Highlights/Accomplishments

**Materials Sciences Subprogram**

***Magnetism at the atomic scale.*** When information is written to a
computer hard drive, local magnetic moments associated with atoms in a
small region of the surface reverse direction like sub-microscopic
compass needles. A new theory has helped explain these dynamical
processes. This work recently received the Gordon Bell Award for the
fastest real supercomputing application and was named to the
Computerworld Smithsonian 2000 collection for being the first
supercomputing application to surpass one teraflop.

***Functional nanostructured materials that replicate natural
processes.*** A newly developed class of nanostructured materials can
selectively filter molecules by their size and chemical identity. These
remarkable materials are made from a solution of molecular building
blocks that spontaneously arrange themselves into a porous solid as the
solvent evaporates. This achievement involved creating the
self-organizing precursors, controlling the pore size, and employing a
novel evaporation process that promotes self-assembly. These materials
hold the promise for significant applications. For example, in the
future we may wear "breathing" fabrics that block hazardous chemicals
while admitting benign species like oxygen.

***The Library of Congress on a single disk?*** The vision that
information can be written and erased near the single molecule limit has
been realized for the first time. Disordering and re-ordering tiny
regions of a thin film show promise for storing a million times more
information than with today\'s computer disks with no increase in space.
The film is made of organic material and supported by graphite. It is so
thin that 40,000 layers would be only as thick as a sheet of paper. By
exposing the film to voltage pulses with a scanning tunneling
microscope, nanometer-sized regions can be switched from crystalline to
disordered, increasing their ability to conduct electricity by 10,000
times. Each tiny region is one bit of information, not much bigger than
a single molecule of the film.

***Analyses of nanocrystals using coherent (laser-like) synchrotron
radiation.*** A powerful new x-ray diffraction method for characterizing
the structure of nanocrystalline solids has been developed. Tailoring
nanocrystalline properties for specific applications depends critically
on detailed knowledge of three-dimensional structure. Traditional x-ray
diffraction methods are inadequate; however, coherent x-ray diffraction
patterns of gold nanocrystals show surface facets, fringes due to
interference among facets, nanocrystal lattice distortion, and,
ultimately, equilibrium nanocrystal shape.

***Ion-implantation for strong metal-ceramic bonds**.* Ceramics are hard
and corrosion resistant but fracture easily. Metals resist fracture but
are not as wear or corrosion resistant as ceramics. Coating a metal with
a ceramic is a way to improve both. However, current coating
technologies can degrade the performance of metals. A new approach has
been successfully developed that employs ion-beam intermixing of the
coating with the metal from collision cascades, which are microscopic
(nanometer-sized) "hot-zones" formed along the ion track. Since the
heating in collision cascades is very short and localized, macroscopic
heating of the metal does not occur. A patent has been filed using this
new approach to improve hip, knee, and dental prosthetic devices. Ion
implantation is used to coat the bone mineral (hydroxyapatite) on
titanium starting with a high density layer bonded well to the titanium
and changing progressively toward a porous bone mineral outer surface
that promotes bone growth and bonding to bone.

***Long-term storage of plutonium.*** Worldwide, nuclear energy
production and defense programs have created 1,350 metric tons of
plutonium. Because plutonium is radiotoxic and has a long half-life
(24,500 years), a long-term storage solution must immobilize plutonium
in materials that are resistant to radiation damage for millennia. Using
heavy-ion irradiation, advanced characterization techniques, and
computer simulation methods, researchers have discovered that highly
durable gadolinium zirconate can lock plutonium into its structure while
remaining resistant to radiation damage for millions of years.

***Boron doping of silicon semiconductor devices \-- faster, lower-power
computing.*** Boron doping of silicon improves electrical conductivity
and other important aspects of silicon device performance. A fifty-fold
increase in active boron doping \-- far above nature's maximum of 0.01
percent \-- has been achieved using a new process involving atomic
hydrogen. Resulting ultra-highly doped silicon layers provide
self-aligned \"metallic\" contacts, improve semiconductor devices,
eliminate etching steps in device fabrication, reduce manufacturing
costs, and minimize the use of toxic etching gases and chemicals.

***Seeing electrons.*** A novel, quantitative, and highly sensitive
method has been developed to image and measure the distribution of
valence electrons, which are responsible for chemical bonding and the
transport of electrical charge in solids. This new technique, combining
imaging and diffraction in the electron microscope, was used to reveal
the spatial distribution of valence electrons in complex structures of
high-temperature superconductors. The ability to directly observe and
measure valence electron distributions with atomic scale resolution will
greatly help in the search for better superconductors, ferroelectrics,
and semiconductors.

***Fluctuation microscopy.*** Fluctuation microscopy, a new discovery,
challenges the common perception that glassy materials have no
organization. Fluctuation microscopy relies on the ability of the
electron microscope to measure diffraction from tiny volumes (\~1000
atoms). It is based on detailed computational simulations coupled with
computer-assisted statistical analysis of multiple electron images. It
has required development of advanced image-detection methods. In one of
the first applications of this method, studies of amorphous silicon and
germanium show that both are highly organized over distances of tens of
atoms, even though other measurement techniques see these atoms as
completely random. This finding is critical to improving the ability of
amorphous solar cells.

***A smart transistor.*** A breakthrough in developing the world\'s
smartest transistor has been accomplished. Germanium-based transistors
using a new ferroelectric dielectric would be "smart" devices capable of
remembering their state. The heart of this new scientific advance is the
understanding of the relationship between polarization and
microstructure and how to control it. This breakthrough offers enormous
potential for energy savings in a myriad of electronic sensors and
devices as no power is necessary to maintain a given on/off state. A
low-power, gigabyte chip could thus serve as a computer hard drive.

***Design of semiconductors with prescribed properties**.* A theoretical
method has been invented by which one can first specify the properties
desired in a semiconductor and then work backward to predict the
structure of the material that will show those properties. This work was
featured in *Fortune Magazine*.

**Chemical Sciences Subprogram**

***Direct measurement of chemical reactions in turbulent flows.*** Long
known for their dramatic advancements in laser instrumentation for
monitoring gas-phase reactions and chemically reacting flows, scientists
at the Combustion Research Facility have for the first time monitored
multiple flame species directly and simultaneously. These measurements
provide a powerful test of combustion models that could lead to improved
combustion efficiency.

***Dynamics of a single molecules.*** Reactions of single molecules have
been observed by monitoring molecular fluorescence using newly developed
experimental methods, thus separating the effects of the motion of one
molecule from the ensemble motion of the molecule in its environment.
The dynamics of a single molecule have been shown to be significantly
different from motion in an ensemble, and should lead to the development
of new theories for predicting chemical reactivity.

***Blinking quantum dots.*** Quantum dots \-- nanometer-size particles
in which electrons are confined in a relatively small volume \-- have
recently been shown to emit light at multiple wavelengths, blinking on
and off on a time-scale of seconds. This remarkable behavior, attributed
to luminescence from different electronic states, has potential
applications for optical logic and photonics and may one day lead to
nano-scale computers and/or portable analytical instrumentation.

***Generation of laser-like x-ray beams.*** Combining state-of-the-art
ultrafast laser systems with evolutionary computer algorithms has led to
a dramatic new demonstration of the controlled generation of coherent
x-rays. This represents an important new source of ultrafast, coherent
soft x-rays for studies of materials properties and chemical physics.

***Biomolecular photobatteries.*** Voltages have been measured from a
single photosynthetic reaction center \-- the five nanometer wide
molecular structure in green plants that captures solar energy and
converts it into electrical energy. The reaction center may be thought
of as a tiny photobattery. The reaction center functions as
nanometer-sized diodes with possible applications to molecular scale
logic devices and computers.

***Radiation induced chemistry.*** Solid particles have been found to
enhance the effects of water radiolysis and the resulting production of
hydrogen. Furthermore, gas bubbles form on the particles and that
impedes the continuous, safe release of hydrogen from the suspension.
These results may provide an explanation for the "burps" in storage
tanks containing aqueous suspensions and radioactive material.

***Plutonium chemistry in the environment**.* Using newly constructed
beamlines at the BES synchrotron radiation light sources, scientists are
now able to study small quantities of radioactive materials. X-ray
absorption studies on plutonium-containing soils from Rocky Flats
revealed that the plutonium is predominantly present as the solid oxide,
PuO~2~, a form substantially less mobile in soil and ground water than
other possible forms. This result demonstrates that the plutonium will
remain stable and has led to substantial cleanup cost savings.

***Actinide supramolecular complexes**.* Researchers have for the first
time built a supramolecular actinide complex. Supramolecular complexes
are molecules that are built from smaller subunits, yet retain their own
distinct molecular properties. While there may be future applications in
separation science and catalysis, the current worldwide effort in
supramolecular chemistry is to understand the principles that govern
assembly of such molecules.

***Molecular theory of liquids**.* A molecular theory for the liquid
state, which has eluded scientists for years, has now been developed.
This provides new opportunities in one of the most important areas for
process engineering and one of its most perplexing problems - the
prediction of liquid-gas equilibria based on the well-known properties
of molecules.

**Engineering and Geosciences Subprogram**

***Engineering at the nanoscale.*** Using nanoscale devices in
real-world engineered systems is one of the greatest challenges facing
nanoscale research. A portfolio of research activities explores how to
engineer at the nanoscale. Recent activities include the development of
physics-based models to represent crack initiation as a nanoscale
phenomenon; studies of the frictional response of nanochains; electric
charge transfer in semiconductor nanostructures; nanoscale quantum-dot
self assembly using DNA templates; and the integration of nanoscale
biomotors with mechanical devices. In this last activity, researchers
constructed integrated nanoscale devices that are powered by
biomolecular motors and fueled by light. In one such system, a protein
from a photosynthetic bacterium generates an electrochemical gradient
across an artificial membrane system. This system is chemically closed,
enabling the motors to be continuously supplied with fuel using a total
light collection area less than 400 square nanometers.

***Geosciences imaging from the atomic scale to the kilometer scale.***
Advances in geosciences imaging were demonstrated this year at a variety
of disparate length scales. At the smallest length scale, the GeoCARS
beamline at the Advanced Photon Source was used to examine the
interaction of liquid water with alumina as a model for understanding
aluminum containing minerals such as clays. Unlike other techniques used
to characterize surfaces, the new beamline can study wet crystal
surfaces. The result showed a significant change from the experiments
using dry surfaces and will help researchers understand water-solid
interactions in nature at the atomic level. At an intermediate length
scale, researchers are using advanced laser scanning confocal microscopy
to image, reconstruct, and characterize fluid flow through pores and
cracks. Predicting the magnitudes and directions of flow in earth
material is critical in performance assessment of oil and gas
reservoirs. Finally, at the largest length scales, researchers are using
specially instrumented regions in an earthquake zone to help model and
improve geophysical imaging on the kilometer scale.

***Biogeochemistry.*** It is increasingly evident that living processes
play a fundamental role in determining the geochemistry of groundwater,
near-surface sediments, and deeper rocks. Microbes affect the weathering
of rocks and minerals, and microbial metabolism affects the accumulation
of heavy metals in soils or their release to groundwater. These and
other processes determine how soils, sediments, and ore bodies form and
how water quality is affected. Work identifying how microbes affect the
fate of zinc released to groundwater percolating through lead-zinc mines
and other biogeochemistry work recently led to the award of MacArthur
Foundation Fellowship to a BES supported researcher. Biogeochemistry,
which links three BES subprograms, is expected to play an increasingly
important role in addressing DOE missions.

**Energy Biosciences Subprogram**

***Completion of the gene sequence of* Arabidopsis thaliana*, the first
plant genome.*** *Arabidopsis thaliana*, a small weed belonging the
mustard family, became the world's "model" plant owing to its small
physical size, small genome size, low level of junk and repetitive DNA,
short life cycle, large number of mutations, and ease in genetic
analysis. An international collaboration involving scientists from the
U.S., Europe, and Japan announced the completion of the complete
sequence of this plant genome in December 2000. The *Arabidopsis* genome
is entirely in the public domain, making the results available to
scientists worldwide. The Energy Biosciences subprogram has been a
partner in this project since its inception; support for research on
*Arabidopsis* dates to the early 1980s.

***Snapshot of a light-driven pump.*** Sunlight causes the
bacteriorhodopsin protein to change shape, and in the process transport
protons across a membrane to provide chemical energy. X-ray
crystallographic structure determinations of this light-driven proton
pump captured for the first time the molecule frozen mid-stroke of this
shape modification. This novel view of the intermediate conformation
enables us to see how biological nanostructures capture and transform
energy.

**Selected FY 2000 Facility Accomplishments**

The four BES synchrotron radiation light sources served 6,009 users in
FY 2000 by delivering a total of 19,854 operating hours to 184 beam
lines at an average of 99.5% reliability (delivered hours/scheduled
hours). The three BES neutron scattering facilities served 524 users in
FY 2000 by delivering a total of10,395 operating hours to 34 beam lines
at an average of 94.7% reliability (delivered hours/scheduled hours).
Statistics for individual facilities are given below.

"Users" are defined by BES as researchers who conduct experiments at a
facility (e.g., received a badge) or receive primary services from a
facility. An individual is counted as one user per year regardless of
how often he or she uses a given facility in a year. "Operating hours"
are the total number of hours the facility delivers beam time to its
users during the Fiscal Year. Facility operating hours are the total
number of hours in the year (e.g., 365 days times 24 hour/day = 8,760
hours) minus time for machine research, operator training, accelerator
physics, and shutdowns (due to maintenance, lack of budget, faults,
safety issues, holidays, etc.).

**The Advanced Light Source (ALS)** served 1,036 users in FY 2000 by
delivering 5,367 operating hours to 34 beam lines at 95.0% reliability
(delivered hours/scheduled hours). The ALS is supported by the Materials
Sciences subprogram.

*New technique for improved storage-ring stability.* The electron beam
parameters in the storage ring determine x-ray beam lifetime and
stability. Using a mathematical technique, accelerator physicists have
understood the strength and location of harmful resonances that cause
irregular, chaotic electron behavior leading to loss of electrons from
the beam.

*Third-harmonic cavities enhance beam lifetime.* The electron beam
lifetime in a synchrotron-radiation source determines how long users can
record data before being interrupted when accelerator operators
replenish the train of short bunches that make up the beam. A desirable
way to increase the lifetime is to lengthen the bunches. Five new
third-harmonic cavities accomplish the bunch lengthening and have
increased electron beam lifetime increased by about 50%.

*X-ray science possible at femtosecond speeds.* X-ray experiments to
study physical, chemical, and biological processes that occur on a time
scale of one molecular vibration (typically 100 femtoseconds) are an
emerging area of research. Three developments at the ALS brought x-ray
science into the femtosecond realm. First, researchers developed a
high-speed x-ray detector (a streak camera) with a picosecond time
resolution. Second, researchers showed how to use a femtosecond laser to
\"slice\" tiny slivers from the circulating electron bunches in the
storage ring and use them to produce pulses of synchrotron radiation
lasting just 300 femtoseconds. Finally, accelerator physicists devised
an arrangement of magnets that allow a narrow-gap undulator optimized
for the production of femtosecond x rays to be installed in the storage
ring.

*Undulator has complete polarization control.* The elliptically
polarizing undulator (EPU) in the ALS is now in full user operation with
a high-resolution beamline to provide state-of-the-art performance. This
capability opens up many new experimental possibilities in polymer,
biophysics, and magnetism research all without rotation of the sample.

*Upgrades improve photoemission electron microscopy.* By imaging the
photoelectrons emitted from a sample with high spatial resolution, the
photoemission electron microscope is an ideal tool for combining
spectroscopy with variable polarization microscopy in the study of
materials ranging from magnetic materials to polymers. The performance
and sample-preparation facility of this instrument have been upgraded,
making possible new experiments, such as probing the magnetic roles of
the different elements in multilayer structures of the type under
development for magnetic memory and data storage.

*A facility for sub-micron x-ray diffraction developed.* Many properties
depend on behavior within individual grains and on the details of
grain-to-grain interactions. The ALS has pioneered the technology needed
for x-ray micro-diffraction and its application to thin-film stress
analysis. The system is capable of measuring structural parameters from
grains as small as 0.7 micron. The technique is starting to play a major
role in many materials projects, from stress-induced cracking of
indented high-strength materials to stress in magnetic thin films.

**The Advanced Photon Source (APS)** served 1,527 users in FY 2000 by
delivering 4,724 operating hours to 34 beam lines at 93.6% reliability
(delivered hours/scheduled hours). The APS is supported by the Materials
Sciences subprogram.

*3-D imaging in real time.* A real-time, three-dimensional x-ray
microtomography imaging system that can acquire, reconstruct, and
interactively display rendered 3-D images of a sample at
micrometer-scale resolution within minutes has been developed. This
system could bring better understanding of an array of physical
processes, ranging from failure in microelectronic devices to growth and
depletion processes in medical samples.

*Novel x-ray microprobe developed.* The magnetic contribution to the
cross section for x-ray scattering is of significant interest. A
technique has been developed that combines microfocusing x-ray optics
with Bragg-diffracting phase retarders to produce a circularly polarized
x-ray microprobe. This will enable a wide variety of magnetic scattering
experiments in applied fields like magnetic materials and
superconducting compounds.

*New beam chopper improves time-resolved experiments.* A new beam
chopper has been developed for time-resolved experiments. The time
window of 10 nanoseconds enables time-resolved experiments in
condensed-matter physics, atomic physics, and biological science.

*Beam-position monitor improvements started.* Significant upgrades have
been made to the particle beam and x-ray beam position measurement
systems. Further progress is expected when these changes are
incorporated in all of the beamlines at the APS. This state-of-the-art
improvement in beam stability will provide the APS users with more
efficient beamlines and the capability of working with smaller samples
and increased measurement resolution.

*Storage-ring "top-up" operations developed.* The APS is the first
facility to implement \"top-up\" filling of the storage with electrons
during normal operations. During 136 hours of top-up operation, the
stored current was held constant to about two parts per thousand by
injecting a pulse of electrons once every two minutes. This resulted in
improvements in x-ray beam stability. Ultimately, top-up filling will be
the routine operating mode of the APS.

*Record FEL SASE achieved.* Using the Low-Energy Undulator Test Line
(LEUTL) and the injector linac, an experimental verification was
obtained of the self-amplified spontaneous emission (SASE) process for
530 nm light. More recently, saturation of the SASE process at a power
level 10,000,000 times higher than the light produced by a single
undulator insertion device was verified. These experiments are viewed as
necessary experimental milestones for achieving an x-ray free-electron
lasers.

**The National Synchrotron Light Source (NSLS)** served 2,551 users in
FY 2000 by delivering 5,620 operating hours to 90 beam lines at 112.9%
reliability (delivered hours/scheduled hours). The NSLS is supported by
the Materials Sciences subprogram and the Chemical Sciences subprogram.

*New optical polarizer.* A newly developed quadruple-reflector optical
polarizer efficiently converts VUV light from linear to either
left-circular or right-circular polarization. This polarizer expands the
capability the U5UA beamline in the area of ultra-thin magnetic films.

*High-resolution photoelectron spectrometer.* A high resolution
photoelectron spectrometer was installed on the U13UB beamline, and has
already produced new physical insights into the electronic structure of
high temperature superconductors.

*Infrared beamlines revitalized.* The 10 year-old infrared
microspectrometer at U10B beamline was replaced with a state-of-the-art
continuum microscope and advanced Fourier transform infrared
spectrometer. The system has been used for the study of interplanetary
materials, biological tissues, corrosion, and materials formed at high
pressure. Also, the beam delivery optics for the U12IR beamline were
rebuilt to provide infrared radiation to a new high-resolution
spectrometer. This spectrometer will be used for magnetospectroscopy
studies of materials such as LaMnO~3~.

*Fluorescence microscopy.* For the first time, an infrared microscope
has been modified such that fluorescence sample visualization and
infrared microspectroscopic analysis can be performed simultaneously.
This unique combination is a valuable analysis tool for probing the
chemical composition of materials.

*Advanced x-ray detector array enables study of trace elements.* X-ray
absorption spectroscopy of trace elements in samples poses a serious
detection problem. The detector technology developed for high-energy
physics applications was used to produce a 100-element energy-resolving
detector array for use on an NSLS beamline.

*Advanced x-ray detector system developed.* One of the ways in which
diffraction experiments can be made more efficient is to detect the
entire diffraction pattern with high resolution. In order to accomplish
this, a novel curved cylindrical detector was developed. In addition, a
highly-parallel readout system was developed that is capable of
processing events 10 times faster than before.

*Low-cost monochromator, low-maintence spectrometer.* A simple device
that consists of a monolithic silicon diffracting element is near- zero
maintenance and almost adjustment free. It is now used on five NSLS
beamlines; several more such detectors will be installed at NSLS and at
other facilities. The new device removes need for ultra-fine mechanisms
that contribute to most of the cost of such an instrument and makes
x-ray monochromators difficult to control.

*Digital feedback system improves storage ring stability.* Meeting the
needs of the large population of NSLS users for high quality photon
beams requires an extremely stable electron orbit. To that end, digital
orbit feedback systems to replace the original analog ones were designed
in both the VUV and the X-ray rings. The main advantage of switching to
a digital architecture is the ability to use a higher number of beam
position monitors to achieve a better match between disturbances on the
beam and corrective action by the feedback system. The digital global
orbit feedback system was put into operations in the VUV ring in August
2000. Implementation of the digital orbit feedback system on the X-ray
ring is expected in FY 2001.

**The Stanford Synchrotron Radiation Laboratory (SSRL)** served 895
users in FY 2000 by delivering 4,143 operating hours to 26 beam lines at
96.8% reliability (delivered hours/scheduled hours). The SSRL is
supported by Materials Sciences subprogram and the Chemical Sciences
subprogram.

*Reliability of SPEAR improved.* The reliability of the injector was
improved by rebuilding the regulation of power supplies in the beam
transport line. This contributed to shorter filling times, and,
consequently, to longer beam times available to the users.

*Quality of the photon beam enhanced.* Stable photon beam intensity is
one of the requirements for performing demanding synchrotron radiation
experiments. Accelerator physics studies determined that one type of
beam noise was due to the excitation of high order electro-magnetic
modes in the accelerating cavities. To alleviate this problem, waveguide
dampers were installed in the radio-frequency accelerating system. As a
consequence, SPEAR operates more reliably and the beam stability is
improved.

*SSRL beam line systems modernized.* Six beam line stations were
upgraded to the SSRL standard data acquisition system and control
software. This greatly increases reliability while reducing user
training time, spares requirements, and staff support requirements.

*High magnetic field x-ray scattering station commissioned.* A new high
magnetic field end station incorporating a 13 Tesla superconducting
magnet was constructed and commissioned on SSRL's premiere x-ray
scattering beam line, BL7-2. This facility is one of the few facilities
in the world that enable state-of-the-art x-ray scattering experiments
in high field environments. The unique matching of a versatile,
high-field magnet with an intense synchrotron x-ray source allows
scientists to unravel the properties of these new materials. Eventually,
the fundamental understanding that will be derived from this research
will lead to higher performance sensors and magnetic storage devices.

*Photoemission beamline improved for higher throughput and resolution.*
The high-resolution angle resolved photoemission beam line station 5-4
has been used to study the fundamental mechanisms of high temperature
superconductivity and improvements in FY2000 have brought the station to
new levels of performance. The upgrades include a new primary focusing
mirror and an angle mode option to the photoelectron energy analyzer
greatly improving throughput.

*Molecular environmental science facility commissioned.* The importance
of molecular based research in the environmental area is increasing in
importance due to the emergence problems ranging from environmental
remediation at the DOE weapons labs, to long term storage of nuclear
waste, to basic questions concerning molecular interactions of
pollutants at the surfaces of soils. Beam line station 11-2 has been
optimized for x-ray absorption studies of samples in a variety of states
and under dilute field conditions. The station also includes
capabilities for small spot analysis as well as specialized facilities
for the safe handling and analysis of radioactive materials such as
soils contaminated with actinides or wastes from nuclear storage sites.

*New research and training gateway program initiated.* A Gateway pilot
program involving SSRL and the University of Texas at El Paso (UTEP) is
providing training and research opportunities targeted toward Mexican
and Mexican American students. In FY 2000, a group of 16 UTEP students
and staff underwent training and carried out experiments on four
separate beam lines.

**The Intense Pulsed Neutron Source (IPNS)** served 230 users in FY 2000
by delivering 3,842 operating hours to 15 beam lines at 101.6%
reliability (delivered hours/scheduled hours). The IPNS is supported by
the Materials Sciences subprogram.

*Upgrade of QENS instrument.* The quasielastic neutron scattering (QENS)
instrument was compleely upgraded. This instrument is used for
measurements that determine the diffusion rates of both molecular
rotation and translation on the typical time-scales of simple liquids,
adsorbates etc. QENS is also capable of measuring vibrational
excitations up to a few hundred meV, providing access to both external
and internal vibrational modes for hydrogenous systems.

*IPNS hosts second National Neutron and X-Ray Scattering School.* During
the two-week period of August 14-26, 2000, Argonne National Laboratory
once again hosted the National School on Neutron and X-Ray Scattering.
The success of the previous year was so overwhelming that additional
funds were provided by BES to increase the size of the school from 48 to
60 graduate students. Funding was also provided by the National Science
Foundation. This school fulfills a continuing need for training graduate
students in the utilization of national user facilities. The formal
program included 32 hours of lectures given by an internationally known
group of scientists recruited from universities, national laboratories
and industry.

**The Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos
Neutron Science Center** LANSCE served 25 users in FY 2000 by delivering
736 operating hours to 7 beam lines at 78.8% reliability (delivered
hours/scheduled hours). LANSCE was down for installation of upgrades and
safety shutdowns in FY 2000. The Lujan Center is supported by the
Materials Sciences subprogram.

*Neutron flux increased.* The Lujan Center is the first spallation
neutron source to exploit the increased neutron flux provided by coupled
moderators. A new coupled liquid-hydrogen moderator provides an increase
of approximately 2.5 times over the previous decoupled moderator. Both
the small-angle diffractometer, LQD, and the Surface Profile Analysis
Reflectometer, SPEAR, benefits from this increased flux at Lujan. The
increase in flux is a result of the interaction of the moderator, the
reflector surrounding the moderator, and the lack of decouplers.

**The High Flux Isotope Reactor (HFIR)** served 269 users in FY 2000 by
delivering 5,817 operating hours to 12 beam lines at 92.9% reliability
(delivered hours/scheduled hours). The HFIR is supported by the
Materials Sciences subprogram and the Chemical Sciences subprogram.

*Cold source progress.* Work continues on the development of the
nation\'s highest-intensity cold neutron source. This cold source, which
will be comparable in intensity to the world\'s best at the Institut
Laue--Langevin (ILL) in Grenoble, France, will support four neutron
guides and instruments. The cold source building and refrigeration plant
have been completed, and the guides and cold-source moderator vessel are
in fabrication.

**The Combustion Research Facility (CRF)** is supported by the Chemical
Sciences subprogram.

*New capabilities brought on line.* The CRF provides a primary interface
for the integration of BES programs with those of DOE's Office of Energy
Efficiency and Renewable Energy and Office of Fossil Energy related to
combustion by collocating basic and applied research at one facility.
Phase II of the CRF more than doubled the laboratory floor space to
37,000 square feet, increasing the number of labs to 37. The new wing
houses unique instruments, such as picosecond lasers for diagnosing
molecular energy transfer. The turbulent flame diagnostics laboratory,
which has become an international standard, has been expanded to
accommodate two simultaneous and independent experimental stations for
visitors. The new laser-imaging laboratory has also been expanded to
include several flame geometries with controlled, reproducible flow
structures. New staff members have been or are being hired in
theoretical chemistry, computer science, and experimental chemical
dynamics.

## Selected FY 1999 Scientific Highlights/Accomplishments

***Serendipitous Applications of Research in the Physical Sciences to
the Life Sciences.*** It has long been recognized that tools and
concepts developed in the physical sciences can revolutionize the life
sciences. One need only consider the impact of x-ray synchrotron
radiation and MAD (multiple wavelength anomalous diffraction) phasing on
macromolecular crystallography; both were developed within the BES
program. In FY 1999, many of the annual BES program highlights
illustrate the rapidity with which advances in the physical sciences are
impacting the life sciences. Two examples are given here. First, new
techniques of nuclear magnetic resonance (NMR) are being used to study
the molecular structures of solid protein deposits implicated in brain
diseases such as Alzheimer\'s Disease and BSE (Mad Cow Disease); both
diseases involve the transformation of normal, soluble proteins in the
brain (whose structure is known) into fibers of insoluble plaque (whose
structure is largely unknown). Second, a nano-laser device has been
shown to have the potential to quickly identify a cell population that
has begun the rapid protein synthesis and mitosis characteristic of
cancerous cell proliferation. Pathologists currently rely on microscopic
examination of cell morphology using century-old staining methods that
are labor-intensive, time-consuming, and frequently in error.

**Materials Sciences Subprogram**

***Seashell Provides Key to Strong Composites.*** Mollusk shells have
evolved over millions of years to provide hard, strong, tough shelters
for fragile occupants. These outstanding mechanical properties derive
from a laminated construction of alternating layers of biopolymer -- a
biologically produced rubber -- and calcium carbonate, commonly known as
chalk. It has been recognized for decades that materials with
alternating hard and soft layers absorb energy and impede cracking.
Unfortunately, it has proven difficult to transcribe seashell-like
designs into manufacturable materials. Now, a rapid, efficient
self-assembly process has been developed for making "nanocomposite"
materials that mimic the construction of seashells. This process can be
generalized and should lead to materials with unprecedented mechanical
properties.

***Imaging Fluid Distribution and Flow in Materials.*** Dramatic
pictures of the distribution and flow of fluids inside intact objects
and porous solid materials have been obtained by magnetic resonance
imaging (MRI) and nuclear magnetic resonance (NMR). The ability to
observe such images and spectra results from the use of noble gases,
particularly xenon, magnetically polarized by means of a laser. This
advance makes possible the observation of MRI pictures and NMR spectra
in ultralow magnetic fields. The technique produces brilliant pictures
(up to a millionfold increase in brightness) and provides a new
capability for noninvasive investigation of flow and transport. The
images and spectra allow the characterization of atomic distribution and
flow from the smallest scale of nanotubes to the largest scale of
macroscopic samples. The flow of fluids through solid materials is a
crucial component of many industrial processes from the catalytic
conversion of petroleum to the containment of toxic environmental
agents. These advances will eliminate the need for high magnetic fields
in some applications of MRI and NMR, a welcomed event given the cost,
bulk, hazard, and lack of portability of the magnets used in
contemporary instrumentation.

***New Fullerene Species Synthesized - Stickyball, C~36~.*** A new
fullerene species, C~36~, has been synthesized and produced in bulk
quantities for the first time. Fullerenes or \"buckyballs\" are hollow
clusters of carbon atoms. They have been studied extensively since the
Nobel prize-winning discovery of C~60~ in 1985 (supported by BES). C~36~
is the smallest fullerene discovered to date and is characterized by
unusual and potentially very useful properties. For example, in contrast
to C60 molecules, which interact only very weakly with one another,
C~36~ molecules stick together -- hence the nickname \"stickyballs.\"
The lower fullerenes, such as C~36~ are predicted to have more highly
strained carbon bonds, resulting in exciting properties for those
molecules such as very high chemical reactivity and high temperature
superconductivity. The synthesis of C~36~ is particularly significant,
because previously it was believed that any fullerene smaller than C~60~
would be too unstable to isolate in bulk.

***Seeing Clearly Now.*** Using a new imaging technique called
Z-contrast imaging, researchers have achieved the highest resolution
electron microscope image of a crystal structure ever recorded,
resolving adjacent columns of silicon atoms separated by a scant 0.78
angstroms (3 billionths of an inch). Better resolution enables
scientists to see and understand important details they had not been
able to see before. This technique also offers both high spatial
resolution and the ability to distinguish different kinds of atoms. The
precise atomic-scale structure of a material controls the performance of
materials for semiconductor devices, superconductors, and a host of
other applications. Combined with improved electron imaging optics
currently under development, this result promises to revolutionize the
atomic-scale understanding of materials.

***New Family of Bulk Ferromagnetic Metallic Glasses for Energy
Efficient Motors and Transformers.*** New rules for designing alloys
have been developed that enable the creation of a family of bulk
metallic glass alloys. These alloys exhibit outstanding ferromagnetic
behavior with virtually no energy loss. These new alloys are at least 65
percent iron plus contain up to seven other elements. Until now, such
alloys could only be produced as thin foils. Commercial transformers
based on the thin foil ferromagnetic metallic glasses are in service,
but their size and application are limited due to difficulties in thin
foil assembly and manufacturing processes. The new bulk glasses can be
cast into exact shapes and substituted into the standard assembly
processes now in use for traditional crystalline materials. It is
expected that the availability of bulk ferromagnetic glasses will
decrease the energy losses of transformers by about 2/3 compared to
today\'s transformers made from crystalline ferromagnetic materials.
That\'s good news for electric utility customers, since it is estimated
that power-distribution transformer losses cost about \$4 billion
annually.

***Universal Magnetic Behavior in High-Temperature Superconductors.***
Understanding high temperature superconductors remains one of the most
significant research issues in condensed matter physics. The observed
properties of two major classes of high temperature superconductors
initially appeared to be significantly different from one other, leading
scientists to believe that the fundamental interactions responsible for
the superconducting behavior were quite different in the two materials.
However, recent neutron scattering results have shown that the
superconducting behavior of both major classes of superconductors is
connected to excitations of the magnetic spin system in each material.
The new results offer insight on high-temperature superconductivity
including the promise that a single physical mechanism can account for
this phenomenon.

**Chemical Sciences Subprogram**

***Measuring Chemical Processes in Combustion One Molecule at a Time.***
A powerful new experimental instrument just completed at the Combustion
Research Facility promises to provide new information about how
molecules dissociate when given enough internal energy. Understanding
such processes is critically important for combustion, because, at the
high temperatures of combustion, dissociation occurs in a variety of
ways that are difficult to observe, model, and predict. In the
experiment, pulses of laser light a few femtoseconds in duration pump
enough energy into a molecule to cause it to dissociate. (One
femtosecond is one millionth of a billionth of a second.) A second
femtosecond laser pulse ionizes the molecular fragment during the
dissociation process. From the simultaneous measurements of the
fragments produced by the second laser, the details of the dissociation
process can be extracted. These measurements are made one molecule at a
time. This new experimental facility promises to be a tool of unrivaled
power for the validation of predictive models and theories of chemical
reactions.

***New Designs for Molecular Wires Help Mimic Photosynthesis.*** One way
to capture and store the sun's energy is to design systems that mimic
photosynthesis. In nature, biological systems use charge separation to
store energy. This charge separation occurs by transfer of an electron
from a photoexcited donor molecule through a bridge molecule to an
acceptor molecule. Researchers have recently constructed
donor-bridge-acceptor systems in which the bridge -- or molecular wire
-- is a conjugated organic molecule analogous to natural carotenes that
transfer charge over long distances. This research may lead to new
molecular devices for efficient charge separation and storage.

***New Insights into Surface Catalysis.*** One of the oldest problems in
surface-catalyzed reactions is understanding how the molecules actually
come together on a metal surface. Researchers studying the hydrogenation
of acetylene on crystalline nickel using sophisticated atomic and
molecular beam preparations and subsequent thermal desorption
spectroscopy demonstrated that this simple reaction proceeds via
hydrogen absorbed into the bulk of the metal rather than adsorbed on its
surface, as previously thought. This startling discovery has changed the
way we think about industrial hydrogenation catalysts such as Raney
nickel and palladium, and may have general implications for
heterogeneous catalysts presently used in energy-intensive industries
such as ammonia production (the Haber Process).

***First Observation of Relativistic Thomson Scattering -- 60 Years
After its Prediction.*** British physicist J. J. Thomson, who identified
the electron in 1897, showed in 1906 that light could cause electrons to
oscillate up and down and reemit at the same frequency in a dipole
pattern; this phenomenon was subsequently termed Thomson scattering.
Nearly a century later, researchers have demonstrated a new phenomena --
relativistic Thomson scattering -- in which electrons oscillate in a
more complex figure-8 pattern and emit light at both the exciting laser
frequency and multiples of that frequency, each emitted in a different
direction. The more complex pattern results from the electron
interacting simultaneously with both the electric and magnetic fields of
the laser light. To observe this phenomena, the research team built a
tabletop neodymium-glass laser and compressed its billionth-of-a-second
pulses by a factor of about 1,000, boosting their power to 4 trillion
watts of very high-quality beam. This experiment is an important
milestone in the study of nonlinear optics with electrons unbound to
atoms. Furthermore, this work may lead to new laboratory tabletop x-ray
sources producing very short x-ray pulses useful, for example, for
probing molecular motion during reactions.

**Engineering and Geosciences Subprogram**

***Making Waves.*** Unfortunately, many facets of nature exhibit chaotic
changes, driven by external forces, never settling down to a predictable
state. Progress has been made in understanding one kind of chaos in
which information travels from one point to another by means of
traveling waves. Examples include the ripples on a wind-blown lake,
light in a laser, weather patterns, and even the fibrillation of a human
heart. In order to understand this kind of chaos, scientists studied the
flow patterns in a thin layer of fluid heated from below. In certain
fluid mixtures, the patterns move laterally like waves on a pond. The
key discovery is that these patterns can be understood in terms of
so-called phase defects, which are places where the waves circle around
a point in a pinwheel-like motion. Looking at only the defects to
understand the entire pattern is much like keeping track of traffic jams
and accidents to understand the operation of a freeway system. The next
step will be to predict how the patterns change with time. If present
ideas are confirmed, they could be useful controlling such important
phenomena as heart fibrillation, and controlling lasers used in
communications, cutting and welding.

***Changes in Seismic Properties of Rocks Detects Damage.*** Seismology
uses the reflection and transmission of elastic waves to locate
subsurface features of interest. Various types of rocks respond
differently to different kinds and frequencies of waves. The theoretical
geophysics program has developed new techniques to study these
phenomena. The research examines rock behavior through ultrasonic
resonance experiments, which show that rock has both a rapid resonance
response and a slow resonance response. The resonance between the
vibrational modes gives the rock a memory of the shaking it has been
through. The resonance behavior has implications for accurately locating
subsurface features, and for understanding strong ground motion damage
patterns during earthquakes when the resonant modes of regions of
different ground properties couple with those of man-made structures. A
similar resonance response is also characteristic of damaged man-made
materials such as metals, ceramics and composites. Thus the nonlinear
elastic wave studies can contribute to understanding and testing the
characteristics of most man-made materials as well as rock or concrete.

**Energy Biosciences Subprogram**

***Orienting Molecular Syntheses.*** A component of plant cell walls
that severely restricts the use of the carbohydrates in plant biomass is
lignin. Lignins are aromatic polymers that make up a significant
fraction of the earth\'s renewable carbon resources. Research has
provided evidence that the biosynthesis of these large polymers from
smaller lignol units does not proceed in a random fashion, as was
previously thought. Novel plant genes have been discovered that encode
proteins that serve as a scaffold, helping to hold the lignol units in
the right orientation as they are joined together by other biosynthetic
enzymes. These results have broad implications for the efficient use of
plant biomass as well as offering new strategies for enzyme catalysis in
an industrial setting.

***Plant Cell Walls.*** The characteristics of plant cell walls -- the
major energy component of renewable biological resources -- vary to meet
the structural, metabolic, and developmental needs of different plant
cell types. The biosynthesis of the plant cell wall is precisely
regulated to conform to these constraints; however, relatively little is
known about how such variation is achieved during cell wall formation.
Researchers recently identified an enzyme responsible for modifying the
xyloglucan polymer backbone, an important factor in determining cell
wall strength. This discovery offers the potential to isolate similar
enzymes that modify cell wall properties. A better understanding of
plant cell wall biosynthesis can eventually improve the properties of
wood and other biomass materials through the efficient design of
specific complex carbohydrates and other renewable carbon resources.

***Designer Enzymes.*** Research on fatty acid desaturases and
hydroxylases has deciphered the mechanism that controls how these two
types of enzymes introduce a double bond (desaturase) or a hydroxyl
group (hydroxylase) at specific sites along the carbon atom backbone of
long-chain fatty acids. This knowledge of the active site of the two
enzymes has enabled the modification of the gene that encodes the
desaturase for a specific fatty acid to change it into the hydroxylase
and vice versa. Both enzymes perform important tasks in altering the
melting response of the fatty acid to heat. This pioneering work lays
the groundwork for future advances in designing vegetable oils---which
have hundreds of potential uses from heart-healthy margarine to
lubricants and nylon.

**Selected FY 1998 Scientific Highlights/Accomplishments**

**Materials Sciences Subprogram**

***Helping to Solve the Mystery of High-Temperature
Superconductivity.*** Understanding high-temperature superconductivity,
discovered in 1987, remains the outstanding problem in modern condensed
matter physics. Recent neutron scattering experiments suggest that the
electric current in high temperature superconductors may be like
"stripes" of flowing current separated by stripes where current does not
flow. These stripes can be static or dynamic (like the stripes on our
flags, waving in the wind). These and other experiments point to a very
different electron pairing mechanism than that seen in low-temperature
superconductors. Once the pairing mechanism is understood, it will be
easier to find materials with higher critical superconducting
temperatures and better mechanical properties.

***Magnetic Resonance Imaging (MRI) Without Magnets***. Striking, high
resolution MRI images have been obtained without the need for high field
magnets or high frequency detectors normally required for MRI. The
breakthrough involves MRI enhancement by noble gases magnetically
polarized (100,000 fold) through laser treatment. A new ultra-low-field
MRI instrument now makes it possible to obtain extremely bright MRI
pictures of polarized samples in the earth's natural magnetic field,
which is thousands of times weaker than fields obtained from traditional
MRI magnets (which are bulky, expensive, and often hazardous). The new
instrument has been used with localized injection of polarized xenon
solutions into human blood to provide the first observations of the
real-time process of xenon penetrating red blood cells. (Xenon is an
inert gas and an FDA-approved anaesthetic.) This combination of
techniques opens the way to provide high resolution MRI images of
localized areas in animal and human subjects.

***Discovery of New Materials Using LEGO.*** Of the enormous number of
combinations of elements in the periodic table, only a very small
fraction are used in real materials. It is quite certain that materials
with optimum properties for various applications have not yet been
discovered. For example, high-temperature superconductivity occurs in
ceramic compounds with a most unlikely combination of elements. A new
strategy using fast computers and concepts from quantum mechanics has
been developed to search for \"winning combinations\" of atoms to
produce materials with improved physical properties. This approach \--
Linear Expansion in Geometric Objects (LEGO) \-- recognizes that even
complex crystal structures can be viewed as a collection of simple
geometric objects such as dumbbells, triangles, etc. By assigning each
geometric object an energy value, computers can rapidly scan hundreds of
thousands of candidates looking for the lowest overall energy and,
therefore, the most stable structures. LEGO has already predicted
several new intermetallic compounds missed through conventional
approaches.

***Electrically Conducting Nanoscale Ropes.*** Incredibly light
synthetic metals with a potential electrical conductivity 50-100 times
better than copper per weight are being made from carbon nanotubes doped
with metals. First discovered in 1991, nanotubes are a new class of
materials formed from graphite-like sheets of carbon rolled into
exquisitely small cylinders. They self organize in the vapor phase
during growth to form well ordered crystalline bundles of individual
nanotubes. The introduction of dopant atoms, such as potassium or
lithium, into the open spaces between adjacent tubes within a rope can
increase electrical conductivity significantly at room temperature.
Doped nanotube ropes are also attracting increased interest as
constituents of novel nanoscale device structures and as replacements
for pure lithium metal in Li ion batteries.

***Molecular Bricks for Nanotechnology.*** Lightweight materials are
commonly composed of polymers, which are long chains of atoms. The
chains are difficult to order completely, which limits their
functionality and durability. Researchers have recently demonstrated new
possibilities for the design of polymers using nano-objects, which can
be regarded as molecular bricks. These bricks, which might have shapes
as diverse as those of nature\'s proteins, create a toolbox for the
design of lightweight materials that could self assemble into structures
with surprising functionality. Using the first elements of this toolbox,
a spherical nanostructure has been created that has internally
continuous channels; some channels transport water and ions, while
others block water but accept organic substances. These nano-sponges
could trap toxic metals from water streams.

***What Makes Stainless Steel Stainless?*** Corrosion damage is
estimated to cost the U.S. 4.2 percent of the Gross National Product
each year. Metals can be used in industrial and technological
applications only when appropriately protected. In the case of stainless
steel and many other metals, protection is provided by a thin oxide film
that prevents further corrosion. However, the structure of these oxide
films has remained a mystery despite decades of study. Recent research
using surface-sensitive synchrotron x-ray diffraction with a combination
of electrochemical experiments has now unambiguously determined that the
oxide film on pure iron has a very fine-grained, nanocrystalline
structure. Results for iron-chromium alloys (e.g., stainless steel) have
shown that the oxide films are also nanocrystalline. This overturns the
long accepted belief that stainless steel is corrosion resistant because
its oxide film is non-crystalline. These surprising results provide a
more realistic basis for understanding corrosion resistance and for the
development of better corrosion protection coatings.

***Do Cracks \"Melt\" Their Way through Solids?*** Predicting and
explaining why, how, and when solids fracture is a significant
scientific challenge. The driving force for fracture is intensification
of the local stress at a crack tip, yet the mechanism by which local
strain is dissipated during crack propagation is not well understood.
Can strain energy be dissipated via "local melting" around the crack
tip? Recent computer simulations of crack formation predict this
intriguing possibility. Simulations indicated that the melting in front
of a crack tip can lead to catastrophic fracture. Using high-voltage
electron microscopy, observations of moving crack tips in an
intermetallic compound confirmed the prediction of the computer
simulations and showed the development of melted and rapidly
re-solidified regions adjacent to the crack tip. This new picture of
fracture as a stress-induced melting process may lead to new approaches
to stress-corrosion cracking in the automotive, aerospace, power
generation, and ship building industries.

***Smart Filters.*** New materials with tailored pore sizes and pore
chemistry can selectively remove deadly heavy metals \-- such as
mercury, lead, and silver \-- from water. Researchers discovered that
precise control over the amount of water in the pores of porous silica
enabled the insertion of useful organic molecules on the walls of the
pores. Using this knowledge, monolayers of organic sulfur compounds were
bound to the internal surfaces of porous silica to prepare selective
filter materials. The high surface area of the porous silica (a few
grams have as much surface area as a football field) coupled with the
bonding characteristics of the organic compounds results in high
filtering capacity and high selectivity for specific contaminants. In
addition, pore openings in the silica are designed to be too small for
microbes to enter and digest the contaminants, later causing human
illness from, for example, mercury contamination. The filter materials
can purify highly contaminated water in a single treatment to a level
that exceeds drinking water standards. The filters can also be recovered
and reused after removing the contaminants.

***A Line in the Sand.*** Granular materials like gravel, salt, or dry
chemicals are ubiquitous in our daily lives and central to many
industrial processes, yet controlling their motion is both surprisingly
difficult and not well understood. For example, granular material
subjected to a driving force remains at rest until a minimum \"critical
force\" is applied; then it moves in uncontrollable events like
avalanches. Inefficiency in handling granular materials may result in
the loss of up to 40 percent of the design capacity of industrial
plants. In its retrospective of the last 50 years, Physics Today
highlighted the emerging science of granular materials as a notable
event of the last decade. Scientists have recently developed a
theoretical approach to describe the motion of granular materials in a
vibrating environment. This theory correctly describes the unexpected
formation of stripe, square, and hexagon patterns on the surface of
vibrated granular media and the formation of localized excitations
called \"oscillons.\" The theory also predicted how to control aspects
of granular motion \-- a prediction that was confirmed by experiment.
The new theory brings the description and control of granular motion to
a higher level of understanding and shows promise of substantial
advances in basic granular science, which can lead to industrial
applications that exploit the controlled motion of granular materials.

***Vortex Matter \-- A New Understanding of Magnetism in
Superconductors.*** Magnetic fields in superconductors are carried by
\"vortices.\" Each vortex consists of a tube of magnetic field
surrounded by a circulating flow of electrons that move without
resistance. It is this free flow of electrons that gives superconducting
materials their special property. Recently, it has been shown that the
system of magnetic vortices can take many forms analogous to the solid,
liquid, and gaseous forms of ordinary matter. The analogy between the
behavior of vortices and ordinary matter is so strong that a new term
has entered the scientific vocabulary \-- vortex matter. Vortex matter
melts from a crystalline to a liquid state in much the same way that ice
melts to water. The properties of vortex matter can be controlled over a
wide range. For example, the density of vortices can be varied by a
factor of 10,000 simply by changing the applied magnetic field. This
remarkable control enables the study of many types of phenomena in
vortex matter whose analogies in ordinary matter are difficult or
impossible to observe. Thus, the identification and characterization of
the melting transition in vortex matter has significant implications for
phase transitions in ordinary matter, for understanding the
electromagnetic properties of superconductors, and for developing
applications of superconductivity.

# Chemical Sciences Subprogram

***Landmark Experiment Challenges Combustion Models***. Combustion is
perhaps the oldest technology in human experience, yet its complexity
limits predictions of combustion processes in devices ranging from
simple laboratory burners to automobile engines. The challenge is
characterizing the influence of chemistry and fluid dynamics on one
another. A simple experiment recently has demonstrated a major error in
current models for combustion processes. The experiment allows the
interaction of chemistry and turbulence to be examined in quantitative
detail for the first time. A planar flame sheet is deformed by a puff of
air generated by a small loudspeaker. Spectroscopic techniques are used
to determine the concentrations of reaction intermediates as the flame
sheet deforms. Comparisons of these experiments with computational
simulations showed that the widely accepted chemical reaction mechanism
for simple methane combustion is in error, thus, requiring a fundamental
change in our models for combustion.

***Fishing for Radioactive Actinides with Molecular Hooks.*** The
selection, separation, and removal of radioactive actinide ions from
complex aqueous waste stream mixtures remain vexing technical issues.
The development of new, improved separation approaches will result in
significant cost savings for nuclear waste treatments as well as improve
environmental safety and materials safeguard security. A new family of
chelate agents or \"chemical fish hooks\" suitable for the reversible
\"catch and release\" of trivalent actinide ions in highly acidic
solutions has been designed, prepared, and characterized. The latest
chelate derivatives show separation characteristics that are especially
suited to practical, batch type waste treatments.

***First Isolation of a Catalytic Oxidation Intermediate.*** Despite
worldwide efforts over the last 15 years on catalytic olefin oxidation,
little progress has been made in extrapolating from ethylene (the
smallest olefin) to larger olefins such as propylene. The key question
\-- the molecular mechanism of ethylene epoxidation (which gives us
anti-freeze and polyester fibers) \-- remains unresolved. Now, a
combined experimental and theoretical tour de force has yielded the
first definitive isolation and spectroscopic characterization of a
stable intermediate in the catalytic process \-- an oxametallacycle.
Calculations were employed to determine the structure for the
oxametallacycle on silver and to predict the infrared spectrum and
molecular motions for that structure. Conclusive identification was
provided by the excellent agreement between the predicted infrared
spectrum and the experimental electron energy loss spectrum.

***Liquid Crystalline Organic Semiconductors Discovered***. Liquid
crystals change their optical properties as they transition between
distinctive geometric states. Digital watch displays, for example, cycle
between transparent and opaque forms. They, like other technologically
important liquid crystals, are electrically insulating. Semiconducting
crystals could have much broader application than insulating crystals,
but large single crystals of these materials are difficult and expensive
to produce. In a recent breakthrough, a family of liquid crystalline
derivatives of perylene diimide was discovered that has semiconductor
properties. The films of one compound self organize from a red,
polycrystalline phase with randomly oriented crystallites into a black
phase with highly ordered ribbon-like structure. The fluorescence
intensity increases seven-fold during the transformation. This
spontaneous change in photophysical properties makes this class of
organic liquid crystals look very promising for future photoconversion
applications.

***Diode Lasers Detect Radiotoxic Isotopes.*** Solid-state diode lasers,
similar to those used in compact disc players, have been used in a new
approach to detect the toxic radioisotope strontium-90, which received
attention because of high levels found in milk after atomic weapons
tests and the Chernobyl reactor accident. Diode lasers excite and
efficiently ionize the strontium atoms; the resulting ions are detected
using a mass spectrometer. The high efficiency allows the detection of
less than one femtogram (femto = 10-15, e.g., a single postage stamp
compared to the area of Texas) of strontium 90. Furthermore, it is
possible to selectively ionize the strontium 90 even in the presence of
large excesses of the stable, naturally-occurring isotopes of strontium.
Measurements can be performed in a few minutes as compared to the
several weeks required previously for conventional radiochemical decay
counting methods. Thus, this new approach should significantly improve
the capabilities for near real-time monitoring of environmental
restoration activities, nuclear weapons tests, reactor accidents, and
the processing of nuclear fuels.

***Photochemical Studies on the Light-Activated Drug Hypericin.*** The
popular herbal remedy St. John\'s wort contains the compound hypericin,
which upon exposure to light is toxic to tumors and HIV, the human AIDS
virus. Now, the fundamental photochemistry of hypericin has been
elucidated. A novel laser spectroscopic technique, fluorescence
upconversion, was used to show definitively that the primary
photochemical process is excited-state intramolecular proton or hydrogen
transfer. Any incomplete proton or hydrogen atom transfers would acidfy
the aqueous solution immediately surrounding hypericin, which may be of
importance in its toxicity to viruses. The study is yet another example
of the role that the physical sciences play in providing fundamental
information relevant to a wide variety of subject areas.

# Engineering and Geosciences Subprogram

***Remote Sensing of Fractures and Prediction of Failure in Rocks***.
Long before catastrophic fracturing and failure of a material, sound
waves transmitted through the material show a dramatic frequency shift.
This shift has been documented before in fractured materials, but the
observation of the shift before the formation of a continuous crack is a
new discovery. Monitoring for the frequency shift can therefore be used
to provide a warning of failure. The sound shifts to a lower frequency
because the high-frequency sound (with shorter wavelengths) is
preferentially absorbed or scattered. Because the frequency shift occurs
prior to creation of a single fracture, there should be a network of
oriented, disconnected features appearing prior to a crack that absorb
or scatter the high-frequency sound in the same way as do observable
cracks. Connected cracks in rocks provide pathways for water, oil, or
pollutant flow. The growth of cracks can improve fluid flow or cause
failure of well-bores, reservoirs, and tunnels or engineered structures;
therefore, it is very important to understand how and when cracks form.

# Energy Biosciences Subprogram

***Building Doors into Cells.*** Before any molecule can enter a cell,
it must first pass through the cell membrane---the thin, fat-containing
film that covers all cells. The passage of most molecules through
biological membranes is controlled by pores, defined openings made with
specific proteins. The composition and structure of pore proteins can
now be altered through genetic engineering. Changes in the size of the
pore, the selectivity of the pore for letting different molecules pass
through, and the pore\'s ability to open and close are three properties
currently being studied by bioengineering new pore proteins. Successful
attempts to engineer modified pore opening and closing properties have
provided insight on how these processes can occur mechanistically as
well as for developing new biotechnological applications. Among the
potential products of this research are chemical triggers or molecular
switches that can be used to create new sensors to detect harmful
chemicals or viruses. Other potential applications are the development
of small light switches and new drug delivery systems.

## Selected FY 1997 Scientific Highlights/Accomplishments

***The Advanced Photon Source (APS) Completes Its First Year of
Operation.*** As the floor of the APS became crowded with experimental
hutches, new results emerged that took advantage of the very high
brightness of this new light source and that could not have been done
elsewhere. While much of the work at the APS and the other BES
synchrotron radiation light sources has been and will continue to be in
the area of materials sciences and condensed matter physics, many
studies are also being done in the areas of biological, plant,
environmental, and geosciences. For example,

\- A new structural determination and biochemical analysis of the human
fragile histidine triad (FHIT) protein has been performed. The FHIT
protein derives from a fragile site on human chromosome 3 that is
commonly disrupted in association with cancers. The understanding of
this tumor suppressor protein will focus on a diverse human HIT family
member in search of their in vivo function throughout biology.

\- The first experiments were conducted with a newly constructed
beamline for geosciences/soil/environmental research. Molecular-scale
observations (made possible by the high brightness of the APS) enable
new understanding of local structural and chemical changes that govern
the mechanisms of mineral-fluid interactions. For example, the molecular
form or speciation of environmental contaminants, such as chromium,
arsenic, lead, uranium or plutonium, determines their toxicity and
bioavailability.

\- Over 90% of the world\'s plants, including essentially all crops,
make use of symbiotic associations with fungi. X-ray imaging studies
performed on these systems using an x-ray microprobe have provided
detailed information on the elemental distribution in plant roots and
associated fungi. These images, with unprecedented spatial resolution,
will be a key to understanding the symbiosis between the plant roots and
fungi.

**Materials Sciences Subprogram**

***Breakthrough in Processing of Aerogel Films.*** A breakthrough in the
processing of ceramic aerogel films won a prestigious award of the
American Chemical Society and was cited as an important discovery by the
Wall Street Journal. This breakthrough overcame the sixty year barrier
to the large scale commercial utilization of these films. Aerogel films
have a foam-like structure, exceptional lightness and transparency, and
are ideal insulating materials for double-paned windows and other uses.
When freshly formed from a liquid, the film can be easy torn until it
has been hardened. Older processes required a toxic liquid and high
pressure and temperature to dry the films. Employing a new understanding
of film drying and chemical treatment of the surfaces of the pores in
the film, a non-toxic, low-pressure and temperature process was
developed to keep the film flexible and resilient as it formed.

***Cool Sounds.*** Air conditioning from your favorite music? Not quite
yet. However, sound, or acoustic energy, has now been used to make
refrigerating and heating units. These devices, called thermoacoustic
refrigerators, or thermoacoustic engines when operated in a heating
mode, have no moving parts and use sound waves in air or helium to
transfer heat. Operation of these devices has been based upon a standing
acoustic wave in a closed system, limiting their usage. Now, a radically
new concept has been devised in which the air or helium would flow
slowly through the device during operation. This concept would allow for
heating and cooling of buildings and for other industrial air
conditioning applications with an economic advantage over current
technology through the elimination of the bulky heat exchangers on
building roofs. First results from a test system operating as a
refrigerator using helium or air have confirmed the concept. Further
developments of this concept are under way.

***Slick and Sticky.*** Pencil-shaped organic molecules called
\"rod-coils,\" designed and synthesized to have half of the molecule
rigid and the other half flexible, were discovered to exhibit unusual
and important clustering mechanisms on several size scales. Aggregates
of these molecules self-assemble into mushroom-shaped clusters with the
rigid ends forming the stems and the flexible coils forming the caps. At
the next level of organization, the mushroom clusters pack side by side
into layered sheets to form, ultimately, a thick film. Because the
building-block molecules are all oriented in the same direction, the
film\'s properties mirror those of the individual molecules, resulting
in a film whose bottom surface is sticky and top surface is slippery.
Such a film has many potential applications, for example as an anti-ice
coating on an airplane wing or an anti-blood-clot lining for artificial
blood vessels. This new molecular organizational technique is being
explored to make films with other properties by replacing the slippery
and sticky groups capping the rodcoils with compounds that perform other
functions, such as conducting electricity or changing their size in
response to an electrical pulse.

***Materials Failure in a Radiation Environment.*** The safe storage of
nuclear materials and radioactive wastes is a major challenge for the
post cold-war generation. The long term effects of radiation on the
physical integrity of these materials and their containers is still
poorly understood. Recent work using simultaneous electron microscopy
and ion irradiation experiments shows that the impact of just a single
high energy ion on the surface of a material has a much greater effect
than previously realized and disrupts tens of thousands of atoms near
the surface of the material. The impact causes local melting,
displacement of many atoms beneath the surface, and the formation of
surface craters and holes. This work should lead to a correct
understanding of how materials are damaged by radiation and will help
explain and predict the behavior of materials used for waste storage and
other applications.

***Powder Process Produces Cheaper Stronger Permanent Magnets.*** A
collaborative team from two laboratories is a recipient of a prestigious
R&D 100 Award for the processing of nanocrystalline composite powder for
high-strength, permanent magnets. The permanent magnet industry is a
very large global industry worth 3.2 billion dollars in 1995 and is
predicted to reach 10 billion dollars by 2010. The high magnetic
strength of the prize-winning neodymium-iron-boron \'super magnets\'
results from matching the crystallite size formed on cooling the alloy
from the melt to the size of the magnetic domains. The previously used
rapid cooling process that creates the fine-grained polycrystalline
material is too expensive for many commercial magnet applications. It
was discovered that adding titanium and carbon to the molten alloy
allows a spray atomization process to create appropriately sized
particles that can be consolidated into magnetic compacts.

***New Process Forms Diamond-Like Boron Nitride Films.*** A process to
grow diamond-like boron nitride films, the second hardest material
known, has been discovered based on a new understanding of how hard
nitride films are formed. Like diamond, films of boron nitride can be
grown from hot gases and plasmas without the use of high pressures.
However, it was recently discovered that irradiation of boron nitride
films with low-energy ion beams will produce films of boron nitride that
contain the hard, diamond-like form rather than the soft graphite-like
form. This new process to form ultra-hard boron nitride films could
revolutionize the tool industry, because, unlike diamond, boron nitride
does not react with iron or steel; therefore, boron nitride is an ideal
material for cutting tools.

***A Microscopic Understanding of Materials Joining Enables the
Intelligent Processing of Materials.*** Welding is a critical
fabrication technology used extensively in a wide variety of industries
such as energy, automotive, construction, aerospace, shipbuilding, and
electronics. Weld failures are among the most common reason for
unscheduled outages in power plants with the cost of replacement power
often exceeding \$1,000,000 per day. Recent advances in materials
joining science have improved our understanding of the welding process
and welded materials. With the help of massively parallel computers,
complex physical models that link both macro- and microscopic scale
phenomena during the melting and solidification of a weld have been
developed. Using such models it is now possible to visualize directly
the solidified weld microstructure for a given set of processing
conditions. The resulting knowledge has been transferred to industry
thereby allowing the intelligent processing of defect-free, structurally
sound and reliable welds.

***Magnetic Refrigeration to Eliminate Harmful Freon.*** Conventional
air conditioning of domestic and commercial buildings, and cooling in
food processing and other industrial plants requires enormous quantities
of electricity and uses huge amounts of environmentally harmful
chlorofluorocarbons (CFCs). Magnetic refrigeration uses the
magneto-caloric effect, the ability of a magnetic material to raise its
temperature upon application of a magnetic field and to lower it upon
removal of that field. For many years the alloys showing this effect
operated only at impracticably low temperatures. New understanding of
thermal and magnetic behavior uncovered a gadolinium-silicon-germanium
alloy that cools efficiently near room temperature. Refrigerator devices
based on magneto-caloric material could cut energy costs and eliminate
ozone-depleting CFCs.

**Chemical Sciences Subprogram**

***\
\"Green\" Separation Process for Hanford Wastes.*** The radioactive
components in the Hanford waste tanks comprise a mere 1/100th of a
percent of the millions of gallons of contaminated waste in storage.
Thus, highly selective removal of the radioactive components could
significantly reduce the volume of waste, which will require very costly
processing and long-term storage. Fundamental studies of technetium
extraction in the 1980s, followed by more recent investigations of the
structural and thermodynamic aspects of the extraction of alkali metal
salts with crown ethers has led to a new technetium extraction process.
The crown ether binds sodium ions already present in the waste, and then
extracts technetium as much as four orders of magnitude better than
others ions in the waste, such as nitrate, which are present at much
higher concentrations. The crown ether complex is readily decomposed by
contact with water to release the extracted technetium thereby affording
a convenient, safe, and economical stripping method. The crown ether is
then recycled thus minimizing secondary waste production.

***New Metallocene Catalysts Lead to Commercial Applications.*** The new
family of metallocene polymerization catalysts, in which polymerization
occurs principally at a single type of metal center with a well-defined
coordination environment, are a substantial advance over the prior
heterogeneous polymerization catalysts. Recent advances on two fronts
\-- strained early transition metals and non-coordinating counterions
\-- have resulted in new commercial applications by Dow Chemical and by
Exxon Chemical. The remarkable stereospecificity features of these new
catalysts have not only led to a variety of new, advanced polymer
products over a wide range of densities, but they also provide the
ability to \"turn a microscope on\" the underlying molecular mechanisms,
thus leading to continually improved catalysts and products. The new
polymers produced from these catalysts are found in wide-ranging
applications from food wrapping to the plastic front end front bumper
combinations on automobiles. The impact of these new products can be
imagined from the Dow Insite process, which produces plastics with a
market of about \$2,000,000,000 per year at Dow\'s Texas plant.

***Joint Program Results in a New \"Smart\" Window.*** Windows with
reduced transmission have been shown to be energy savers by reflecting
some of the heat from solar radiation. However, such windows have fixed
transmission that also reduces visible light. On a cloudy day a building
or home equipped with such windows may not have adequate natural
lighting. Research jointly supported by BES and the Department\'s Energy
Efficiency program has led to the initial development of a self-powered
\"smart\" window that can control its own transparency. Integration of
two technologies, electrochromic windows and dye-sensitized solar cells,
yields a smart window that darkens, reversibly, when exposed to
sunlight.

**Engineering and Geosciences Subprogram**

***Fast-Transport Predicted in Subsurface Fluids.*** Underground flow
properties of fluids containing two or more components (oil(s)/water)
are a major issue for environmental remediation. New experimental work
documents how upward and downward flow of different fluids can be driven
by differences in their density and their tendency to diffuse. Such
transport occurs much more rapidly than has been predicted by earlier
models. This new research developed innovative experimental methods to
test the earlier predictions, and successfully measured and modeled the
effects of multiphase flow in simple porous materials. This work is a
significant step towards developing improved models to make better
predictions for complex and highly variable natural subsurface
environments.

**Energy Biosciences Subprogram**

***New Sensor Provides Instant Litmus Test for Pathogens.*** A new class
of colorimetric sensor materials has been invented that makes it
possible to instantaneously and inexpensively detect a wide range of
biological toxins and common disease-causing organisms. Building on
earlier discoveries, researchers have developed a thin film consisting
of receptor molecules attached to a film of linked diacetylene
molecules. The film transmits blue light. The surface receptor molecules
are designed to very selectively bind specific pathogens causing the
film molecules to reorganize and the film to turn red. Pathogens thus
far detected with good sensitivity include an influenza virus, cholera
toxin, botulism toxin, and the toxin produced by the bacteria
responsible for 200 deaths per year in the US alone, as noted by the
recent contamination of fruit drinks and fast food hamburgers. Existing
tests for all of these pathogens require at least a 24 hour culture.
After further development, the sensors can be placed on plastic, paper,
or glass and incorporated into inexpensive packaging and portable
detection devices.

***Silicon in Biology.*** Silicon is an element that is a principal
component of glass, computer chips, coatings and numerous consumer
products. There are only a few biological systems that metabolize this
element. Silicon is metabolized by some simple animals, by algae to make
the equivalent of glass houses, and by some higher plants (the rough
feel of corn leaves comes from shards of silicates in the leaves).
Recently a gene was identified that encodes a protein that is involved
in binding and transporting silicon into a cell. This discovery will
extend our understanding of how silicon is taken up and processed by
biological systems which may lead to applications such as the mining of
silicon from seawater and the manufacture of silicon-containing
products.

***Bioproduction of Natural Gas.*** The few microorganisms that possess
the ability to produce methane (natural gas) have been studied for a
number of years in the hope of using these organisms to produce a
renewable energy source. Last year the genome of a methane-producing
bacterium was sequenced which showed the uniqueness of these organisms.
It is now thought that these bacteria are among the first life forms
ever developed on earth. Recently, procedures have been developed which
will permit the genes of methane-producing bacteria to be manipulated.
This development will allow scientists to determine the nature and
properties of these organisms and their unusual metabolism.

***Controlling Natural Energy Resources through Plant Genetic
Engineering.*** Cellulose is the most prevalent biological compound on
earth. It is the principal component of all plants, wood, paper and
cotton. When considered globally, cellulose constitutes an enormous
supply of chemical energy, all of it renewable. Recently, several plants
have been manipulated to make significantly less cellulose. This
modification is important because it may now permit identification of
the factors that control the synthesis and deposition of cellulose and
related compounds. This development may permit the genetic engineering
of plants to produce either more cellulose, or plants that produce
larger amounts of other chemicals such as liquid fuels and plastics.

[^1]: BES defines \"users\" as researchers who conduct experiments at a
    facility (e.g., received a badge) or receive primary services from a
    facility. An individual is counted as one user per year regardless
    of how often he or she uses a given facility in a year. "Operating
    hours" are the total number of hours the facility delivers beam time
    to its users during the Fiscal Year. Facility operating hours are
    the total number of hours in the year (e.g., 365 days times 24
    hour/day = 8,760 hours) minus time for machine research, operator
    training, accelerator physics, and shutdowns (due to maintenance,
    lack of budget, faults, safety issues, holidays, etc.).