**Research Activity: Atomic, Molecular, and Optical Science**

Division: Chemical Sciences, Geosciences, and Biosciences

Primary Contact(s): Eric Rohlfing (<eric.rohlfing@science.doe.gov> ;
301-903-8165)

Team Leader: Eric Rohlfing

Division Director: Walter Stevens

**Portfolio Description:**

The AMOS activity supports experimental and theoretical studies of the
fundamental properties of atoms, ions, and small molecules and the
interactions between electrons, photons, and ions in collisions with
atoms, molecules, and surfaces. Research is aimed at the most complete
quantum mechanical description of such properties and interactions.
Topics of interest include: studies of the interactions of intense
electromagnetic fields, induced by highly charged ions or lasers, with
atoms and molecules; coherent control of quantum mechanical processes;
development and application of novel x-ray light sources in advance of
next generation light sources; theory and experiment on ultracold
collisions and quantum condensates.

**Unique Aspects:**

The underpinning aspect of the AMOS activity gives it a unique
relationship with BES activities that utilize photon, electron, neutron,
and heavy ion probes at the BES user facilities. The relationship will
continue to be exploited, particularly with respect to forefront
research into the generation and application of ultrashort, intense
x-ray pulses. The AMOS program is the sole supporter of
synchrotron-based AMOS studies in the U.S., which includes ultrashort
x-ray pulse generation and utilization at the ALS and APS. The AMOS
program continues its role as the principal U.S. supporter of research
into the properties and interactions of highly charged atomic ions,
which is of direct consequence to fusion plasmas. The program supports
unique ion source/trap and accelerator facilities to conduct this work.

**Relationship to Others:**

The AMOS activity funds with BES Materials Science the ultrafast x-ray
beamline at the ALS. The program has had substantial participation in
the continued development of the scientific case for the Linac Coherent
Light Source (LCLS), and several AMOS PIs serve on the LCLS Scientific
Advisory Committee. Fundamental insight and data obtained in the AMOS
activity are relevant to FES programs in atomic data for fusion modeling
and basic plasma physics. This synergy is particularly noticeable at the
Multicharged Ion Research Facility (MIRF) at ORNL, which is co-funded by
BES and FES. There is overlap in the interactions of intense laser
fields with high-energy plasmas relevant to defense programs in DOE. A
close working relationship exists with the NSF Atomic, Molecular,
Optical and Plasma Physics Program, and these two programs co-fund the
NAS/NRC Committee on Atomic, Molecular and Optical Science (CAMOS). In
2002, the AMOS Program provided partial support for the Gordon
Conference on Multiphoton Processes and the 8^th^ International
Conference on X-Ray Lasers. The program had active participation in the
workshop at PNNL on Understanding the Role of Water in
Electron-Initiated Processes and Radical Chemistry that involved both
chemical physicists and radiation chemists supported by BES.

**Significant Accomplishments:**

During the past five years, the AMOS activity has been a major U.S.
supporter of experimental and theoretical studies of the fundamental
properties of atoms, ions and small molecules and of collisional
interactions between atoms, ions, molecules and surfaces. This has lead
to the acquisition of a vast database on the properties of atoms, ions
and small molecules. This information is now being used to manipulate
the quantum behavior of these species. It has also lead to the
development and application of powerful new methods for momentum imaging
of collision fragments that have seen wide application in atomic,
molecular, and chemical physics. More recently, the initiative on Novel
X-Ray Light Sources has lead to the further development and scientific
application of ultrafast x-ray sources using table-top lasers and 3^rd^
generation synchrotrons (ALS and APS). Quasi phase matching of
high-harmonic generation for soft x-ray production has been demonstrated
and fundamental interactions of intense and controllable laser fields
with atoms and small molecules leading to ionization and fragmentation
have been examined. New projects in FY2002 focused on electron-driven
processes in gaseous and condensed phases, the production and
utilization of ultracold molecules and multidimensional spectroscopy for
characterization of the optical properties of nanoscale materials. Prof.
John Thomas of Duke University observed a possible superfluid transition
in an ultracold Fermi gas, an observation with important ramifications
for our fundamental understanding of cooperative phenomena in Fermionic
systems. Prof. Philip Bucksbaum at the University of Michigan took the
first steps toward creation of an ultrafast x-ray switch in work done on
laser-modulated x-ray diffraction at the Advanced Photon Source. Dr.
Fred Meyer at ORNL performed benchmark studies of how highly charged
ions are neutralized in collisions with metal surfaces using the MIRF at
ORNL. Dr. Debbie Jin of JILA/University of Colorado was awarded the 2002
Maria Goeppert-Mayer Award by the American Physical Society for her
pioneering work on quantum degenerate Fermi gases. In 2002 four AMOS PIs
were named Fellows of the American Physical Society; 68% of the current
PIs in the program are now Fellows.

**Mission Relevance:**

AMO Science underpins a wide spectrum of BES research activities and
lays the foundation for enhanced future utilization of BES light
sources, electron beam microcharacterization centers, and neutron
scattering facilities. The knowledge and techniques acquired through the
AMOS program have potential impact in the development of new probes of
matter in the gas and condensed phases using photons, electrons, and
ions; on our understanding of nanostructured materials; and on our
ability to model low- and high-temperature plasmas. AMOS contributes at
the most fundamental level to the science-based optimization of current
energy sources and the development of new ones.

**Scientific Challenges:**

AMO science is currently undergoing a transition from a field in which
the fundamental interactions of atoms and molecules are probed to one in
which they are *controlled*. The enormous database of knowledge acquired
over the last several decades and the powerful technical innovations in
laser technology are the two forces driving this transition. AMOS
practitioners can now shape the quantum mechanical wavefunctions of
atoms and small molecules using controllable laser fields, trap and cool
atoms (and soon molecules) to temperatures near absolute zero where
condensation into a single quantum state occurs, create coherent matter
waves by manipulating quantum condensates, create novel surface
structures using highly charged ion beams, and coherently drive
electrons in atoms so that they generate high-harmonic radiation in the
soft x-ray region.

**Funding Summary:**

**Dollars in Thousands**

**[FY 2002]{.underline}** **[FY 2003 Request]{.underline}** **[FY 2004
Request]{.underline}**

11,815 11,815 12,275

.

> **[Performer]{.underline} [Funding Percentage]{.underline}**
>
> DOE Laboratories 39.0%
>
> Universities 60.0%
>
> Other 1.0%

These are percentages of the operating research expenditures in this
area; they do not contain laboratory capital equipment, infrastructure,
or other non-operating components.

The program provides funding for 47 university grants supporting about
60 students and partially supporting about 55 faculty and senior staff.
It also funds 3 programs at national laboratories supporting about 15
senior staff and 3 students and postdocs. Programs at the laboratories
are multi-investigator efforts focusing on problems that require
extensive participation by experienced scientists. These programs
usually underscore the user facilities at the SC laboratories, including
the Multicharged Ion Research Facility (MIRF) at ORNL, the ALS at LBNL
and the APS at ANL. A new program at LANL on optical properties of
semiconductor quantum dots, which was funded under NSET in FY2002, is
strongly affiliated with the nascent Center for Integrated
Nanotechnologies at LANL/SNL. The program supports the J. R. MacDonald
Laboratory at Kansas State University: a multi-investigator program and
BES Collaborative Research Center devoted to the experimental and
theoretical study of collisional processes involving highly charged
ions.

**Projected Evolution:**

Coherent control of nonlinear optical processes and tailoring quantum
mechanical wavefunctions with lasers will grow in importance. Such
control will be vital to the ultimate realization of laser-controlled
chemistry and to our ability to store and read information in quantum
systems.

The development and application of novel x-ray light sources using
existing synchrotrons or table-top lasers will continue. Topics of
interest include the development of high-harmonic generation or its
variants as useable soft x-ray sources, development and characterization
of femtosecond pulses of x-rays at existing synchrotrons and
applications in the chemical and materials sciences.

AMO science plays a strong role in nanoscale science efforts.
Opportunities include the development of AMO theory for artificial
quantum structures in materials, the utilization of light force trapping
and cooling to create ultracold samples of atoms and molecules including
quantum condensates, the use of nonlinear spectroscopies to characterize
the optical properties of nanoscale materials and the manipulation of
condensates to create coherent matter waves. Quantum condensates of
bosons and fermions represent novel nanostructures whose properties
(superfluidity, Cooper pairing, etc.) increasingly blur the boundary
between atomic and condensed matter physics. Coherent matter waves offer
dramatic opportunities for atom lithography on the nanoscale.

Fundamental studies of highly charged ions and their interactions with
atoms, molecules, and surfaces will continue to further develop the
knowledge base important to fusion plasmas. A new thrust area related to
this effort will be to utilize the experimental and theoretical tools of
AMOS in the study of low-energy electron-molecule interactions in the
gas and condensed phases. Such interactions play vital roles in
determining the subsequent chemistry in low-temperature plasma
processing, which is used extensively in the semiconductor industry and
in radiation environments such as mixed-waste storage tanks.

November 13, 2023