bluuebunny/crossref_metadata_2025 huggingface dataset:
Intra‐ and Intermode VibrationalEnergy Flow in CH3F Excited byIrradiation With an Intense CO2Laser: A Non‐Linear VibrationalRelaxation
Authors: Nakane Hideaki , Tsuchiya Soji
Published: March 2007

The vibrational relaxation mechanism of CH3F whose ν3 mode is excited by a transversely
excited atmospheric (TEA)CO2 laser‐pulse has been discussed on the basis of
observation of the laser‐induced fluorescence (LIF) of the ν3 overtones and of the C–H
stretching modes and kinetic analyses. The time‐evolved LIF in the 3‐μm region was
found to be dependent significantly on the laser fluence; at a low fluence (<0.01 J cm−2),
the emission intensity increased almost exponentially with a rate similar to the one
determined in the experiment with a Q‐switched laser, while at a higher fluence
(>0.1 J cm−2) the emission rose much faster to form a peak which decayed quickly
before a second broad peak appeared. In the wavelength‐resolved fluorescence
measurement, it was found that the kinetics of population in the ν4 level were similar to
those in the 3ν3 level, while those in the ν1, 2ν5, ν2 + ν5 and 2ν2 levels behaved in a way
different from those in the ν4 level. These observations lead to the conclusion that the
laser energy poured into the ν3 mode flows to the ν4 level directly through 3ν3 as well as
by the successive inter‐ and intramode V–V energy transfers, i.e., ν3→ν6→ν2, ν5→2(ν2, ν5)→ν1→ν4. A model calculation of the relaxation kinetics, including the
direct V–V energy transfer between two 3ν3 and ν4 levels, could reproduce the 3‐μm
emission data. Another significant finding is a non‐exponential depopulation in the 2ν3
level, the ν4, ν1 and other vibrational levels in the 3‐μm region in the final stage of the
relaxation. The deactivation rate is larger for a higher level and is a decreasing function
of time and is much larger than the V–T/R energy transfer rate. determined in the experiment of weak laser excitation. This may be attributed primarily to the successive
intermode V–V energy transfers from the 3ν3 to the ν4, ν1, 2ν5, . . levels which lie
between the 2ν3 and 3ν3 levels. This process may be repeated if the intramode V–V
energy transfer from the 2ν3 to the 3ν3 level occurs. The deactivation mechanism found
in this experiment is called ‘catastrophic cyclic path’ which is effective until the relative
population distribution in relevant levels between 2ν3 and 3ν3 becomes that in equilibrium
at the translational temperature of the CH3F gas.
The Mechanism of Occurrence of Dual Fluorescence in Intermediate Case Molecules as Viewed From Rotational Effects
Authors: Sekiguchi Osamu , Ohta Nobuhiro , Baba Hiroaki
Published: March 2007

Fluorescence decays of jet‐cooled pyrazine excited at various positions of rovibronic
transitions within the 0–0 band were measured by the use of a pulsed dye laser pumped
by an excimer or a nitrogen laser. The experimental data thus obtained on the number
(N) of the triplet states coupled to the initially excited singlet rovibronic state were
analyzed and interpreted by the aid of computer simulation using an asymmetric rotor
program. The results indicate that the extraordinarily great variation of N with excitation
energy and unreasonably small values of N hitherto reported in the literature can be understood
in terms of the conventional theory based on the singlet–triplet mixed state
model which has been developed for elucidating the mechanism of the occurrence of
dual fluorescence in intermediate case molecules.
On the 1986 Nobel Prize in Chemistry
Authors: Durup Jean
Published: March 2007

A review is given of some major trends in the work of the 1986 Nobel prize winners in chemistry, D.R. Herschbach, J.C. Polanyi and Y.T. Lee.
Comparison of the Photoisomerization andRelaxation Processes Studied byTime Resolved SpectroscopicMethods in Two PolymethineDyes With the Same PolymethineChromophor
Authors: Rentsch S. , Grummt U. W. , Khetchinashwili D.
Published: March 2007

A streptocyanine dye (BMC) and an oxadicarbocyanine (DODCI) were studied in the
picosecond and millisecond time region. The comparison showed that for both dyes the
following parameters are nearly equal: the radiative lifetime, the difference between the
absorption maxima of the stable form and the photoisomer, the activation energy and
the frequency factor for the thermal backreaction and even the energy barrier in the
excited state.

The dyes show strongly different kinetics in the excited state. BMC relaxes faster by
about 2 orders of magnitude than DODCI and shows a much higher photoisomerization
rate. In accordance with Eyring′s theory the higher relaxation and isomerization rate of
BMC is connected with an entropy increase in the transition state.
Frequency Dependent Kinetics ofthe CW CO2 Laser InducedReaction of CF3CF2Cl
Authors: Zitter R. N. , Koster D. F. , Siddiqua N.
Published: March 2007

Kinetics of the decomposition of CF3CF2Cl at 50 torr by a cw CO2 laser have been studied over a range of laser frequencies extending 36 cm−1 below an absorption band
center at 980 cm−1. At constant translational temperature, the change in the rate constant with laser frequency is a factor of 100, comparable to the effect previously observed in CF2ClCF2Cl. Arrhenius plots show an activation energy of 86.2 kcal/mole, independent of frequency.
Intracavity Gain Detection Applied to Transient Inversions of IF
Authors: Williamson R. L. , Hanko L. , Davis S. J.
Published: March 2007

A CW dye laser has been used to study transient optical gain on the B →X electronic
transition of iodine monofluoride. By placing the gain generator inside the CW dye laser
cavity, gain was readily observed even at levels too small to support lasing in a low loss
cavity. Transient phenomena, including V–T energy transfer, were easily observable.
An analysis of the intracavity gain detection technique revealed a method for estimating
optical gain. The technique should be readily applicable to other systems.
Multiphoton Absorption of 12CF3I,13CF3I, CF3Br and SF6 by a HighPressure CO2 Laser
Authors: Angelié C. , Capitini R. , Girard P.
Published: March 2007

An investigation of the IR multiphoton absorption (MPA) of 12CF3I, 13CF3I, CF3Br and SF6, excited in cell by a 10 Bars TE CO2 laser is reported. The spatial, spectral and temporal characteristics of the laser emission versus the grating position have been
carefully investigated. The main result is that the peaks observed in the different MPA spectra are undoubtedly correlated to the gain curve of the laser and not to the fine molecular spectroscopy.

This result is discussed in comparison with published similar works. The most likely explanation involves a laser bandwidth effect associated with a background of weak but rather dense resonances (typical spacing of 0.1–0.2cm−1). The MPA cross section of 13CF3I is about half that of 12CF3I pointing out the probable rôle of Fermi resonances.
Laser‐Induced FluorescenceStudy on Reactions of C+(2P) andC(1D,1S) With Alcohols Leading toCH(X2Π) Radicals atThermal Energy
Authors: Tsuji Masaharu , Nagano Ichiro , Nishiyama Nobuaki , Sekiya Hiroshi , Nishimura Yukio
Published: March 2007

Thermal energy reactions of C+(2P) and C(1D,1S) with CH3OH, C2H5OH, n‐C3H7OH
and i‐C3H7OH to give CH(X2Π) radicals have been investigated by observing laser‐induced
fluorescence (LIF) spectra of CH(A—X) in a flowing afterglow. In the hydride
ion abstraction by C+(2P), only CH3OH exhibited the CH(A—X) LIF spectrum with a
vibrational distribution of 1.0: 0.62 for v″ = 0 and 1, respectively. On the other hand,
the CH(A—X) LIF spectra exclusively from v″ = 0 were observed in the reactions of
C(1D,1S) with all alcohols studied. By isotopic substitution for CH3OH it was shown that
the CH(X) radicals arise from the selective attack on the methyl site in the reactions of
C+(2P) and C(1D,1S) with methanol.
Bridged Quaterphenyls as Flashlamp‐Pumpable Laser Dyes
Authors: Kauffman Joel M. , Kelley Charles J. , Ghiorghis Alem , Neister Edward , Armstrong Lorne , Prause Paul R.
Published: March 2007

Partial bridging of the o,o′ positions of the aromatic rings in quaterphenyl gave superior
flashlamp‐pumpable laser dyes. Alkyl‐substituted carbon bridges gave superior dyes to
those containing oxygen or alkyl‐substituted nitrogen or silicon bridges. Dyes lasing in
the 365–390 nm region with improved energy output, lifetime and solubility were
discovered.
Multiphoton Ionization of Formaldehyde: Observation of 3py and 3pzRydberg States
Authors: Bomse D. S. , Dougal S.
Published: March 2007

Multiphoton ionization (MPI) of CH2O and CD2O is reported for dye laser wavelengths
between 445 and 470 nm. The ionization pathway starts with three‐photon resonant
absorption to 3py and 3pz Rydberg states. One or two additional photons are required,
depending on wavelength, to reach threshold. MPI spectra agree well with VUV
absorption measurements of the same Rydberg levels. MPI yields are small and photoacoustic
measurements imply the initial three‐photon excitation has low probability.
Transitions at the four‐photon ionization threshold show larger cross sections than the
(overall) five‐photon ionization bands but hot band transitions were not observed
following selective vibrational excitation of ground state molecules.
Investigation of Solvent Dependence of Intermolecular Proton Transfer by Picosecond Absorption Spectroscopy
Authors: Kaschke M. , Granesz A. , Kleinschmidt J.
Published: March 2007

A picosecond absorption study on the
intermolecular proton transfer of photoexcited
8‐hydroxy‐1,3,6‐pyrene trisulfonate (HPTS)
is presented. The time of formation of deprotonated
excited HPTS was measured for various
solvents. The dependence of this time of
formation on the methanol fraction in watermethanol
mixtures is discussed in terms of a
simple cluster model. Proton transfer rates
were determined in different micellar systems
yielding information on the character of the
micellar surrounding of the proton donator.
IR‐Luminescence of CF2Cl2 Molecules in Multiple‐Photon Excitation With Co2‐Laser Radiation
Authors: Dem′Yanenko A. V. , Polyakov G. A. , Puretzky A. A.
Published: March 2007

We studied the IR luminescence spectra of vibrationally excited CF2Cl2 molecules
resulting from excitation of the ν1 (1098 cm−1) and
ν8 (922 cm−1) modes with a pulsed CO2 laser.
The nonequilibrium spectra obtained under pumping conditions where their equilibrium counterparts
coincide (the number of the photons absorbed per molecule being the same) were found to differ considerably.
We suppose that this difference is due to different types of vibrational distribution formed as a result of the IR laser pumping.
When pumping the ν1 mode, excitation of the R‐branch occurs, resulting in the
molecules “sticking” on the lower vibrational levels, whereas in the case of the ν8 mode,
it is the P‐branch that gets excited so that the molecules become easy to raise to high‐lying vibrational levels.
Alanine Formation in Aqueous Solution of Ammonium Acrylate Induced by UV Picosecond LaserPulses
Authors: Khoroshilova E. V. , Kuzmina N. P. , Matveetz Yu. A.
Published: March 2007

Formation of amino acids (α‐ and β‐alanine) and oligomers containing NH2‐groups, have been discovered under the irradiation of aqueous solution of ammonium acrylate by picosecond laser pulses with intensity up to 1 GW/cm2, λ = 266 nm.

The composition of photoproducts was shown to depend on intensity of laser pulses. The laser intensity dependence of the β‐alanine quantum yield was of a nonlinear character. The β‐alanine formation occurred under the excitation of highly singlet electronic states of ammonium acrylate molecule by two quanta of UV or one quantum of VUV light. The unimolecular mechanism of amino acid formation in such a reaction was suggested.
Diode Laser Spectroscopy of the Dynamics of Multiphoton Excitation of SF6 Molecules byCO2 Laser Pulses
Authors: Kuritsyn Yu. A. , Makarov G. N. , Pak I. , Sotnikov M. V. , Zasavitsky I. I. , Shotov A. P.
Published: March 2007

The dynamics of excitation by CO2 laser pulses of SF6 molecules from individual
rotational sublevels J″ of the ground vibrational state have been investigated in a pulsed
molecular jet under essentially collisionless conditions. At different energy fluences of exciting laser pulse Φ = 10−5 + 10−1 J/cm2, the dependences of the fraction fJ of excited molecules on the rotational quantum number J″ have been obtained,
when SF6 molecules were excited on the 10P(16) CO2 laser line, as well as on the 10P(18) and
10P(14) lines at Φ = 0.1 J/cm2. Comparison of experimental results with theoretical
predictions18–20 shows rather strong disagreement between theory and experiments both
in the population of the υ3 = 1 state and in the role of multiphoton transitions.
It is shown that the narrowing of the exciting laser pulse spectrum (the 10P(16) line,
Φ ≲ 10−2 J/cm2) results in drastic decrease of the fraction of excited
molecules from the (υ3 = 0, J″ = 4) state which is most resonant with laser
radiation.
Isotopically Selective Infrared Multiple‐Photon Dissociation ofMoF6 by a H2‐Raman Laser
Authors: Oyama Toshiyuki , Satooka Sakae , Kato Shuji , Midorikawa Katsumi , Tashiro Hideo , Takeuchi Kazuo
Published: March 2007

Infrared multiple‐photon dissociation (IRMPD) of MoF6 has been investigated with a parallel
beam of a para‐H2 Raman laser newly developed by our group. MoF6 gas
(2 Torr, natural abundance) was put into in a static cell cooled to −58℃ and was irradiated with the laser line
at 728 cm−1. The critical fluence of 0.11 Jcm−2 for complete dissociation was determined
by analysis with a Gaussian beam model. Irradiation at the lower frequency side (728 cm−1) of
the MoF6 ν3 band enriched the lighter isotopes in the residue.
A maximum value for selectivity of 1.1 was obtained.
Transient Isomerisation and Inverse Electronic Relaxation of Infrared Multiple‐Photon ExcitedPentafluoropyridine
Authors: Chowdhury P. K. , Rao K. V. S. Rama , Mittal J. P.
Published: March 2007

Pentafluoropyridine (PFP) undergoes fast structural isomerisation to fulvenes when irradiated
with 9R(16) CO2 laser line in the fluence range 0.5–1.5 J/cm2.
The unstable fulvenes slowly decay back to PFP in ms time scale. No detectable permanent dissociation of PFP
was observed in the above low fluence experiments. However, by using focused CO2 laser beam
for the irradiation of PFP, an emission of light in the visible/near‐UV was observed. The time evolution of the
luminescence reveals three peaks at 390, 460 and 500 nm on a broad background emission of 300–680 nm.
These bands are assigned to the fluorescence of PFP via inverse electronic relaxation (IER) and C2
Swan bands. On prolonged irradiation of PFP in focused condition a small extent of permanent dissociation
was observed with the major products as C2F4, a sooty yellow deposit and another
compound presumed to be Dewar PFP.
Kinetics and Mechanism of Transformations of Aliphatic Alcohol Molecules Under Multiphoton IR Excitation
Authors: Zhitneva G. P. , Markina I. A. , Pshezhetskii S. A.
Published: March 2007

The main channels for transformations of C2H5OH,
iso‐CH3H7OH and n‐C3H7OH molecules
under IR multiphoton excitation are the monomolecular reactions of dehydration (1), and Cα − Cβ
bond breaks (2). The ratio of the yields of reactions (1) and (2), γ, is determined by
the molecules′ structure, radiation energy density, the pressure of alcohol vapors and inert gas.
The direction of the alcohol molecules′ transformations under IR MPE, under thermal equilibrium conditions,
differs from pyrolysis, when the chain processes of C2H5OH and
C3H7OH molecules dehydrogenation, and CH4 splitting‐out from
n‐C3H7OH molecules are developing. Reactions of H and CH3 radicals
with alcohol molecules under laser initiation do not lead to the development of chains due to the high rate of
H atoms diffusion from reaction zone and effective
recombination of CH3 radicals.
Kinematic Effects on Laser‐induced Fluorescence Measurements Performed in Reactive Crossed Beam Experiments
Authors: Naulin Christian , Costes Michel , Benseddik Asmae , Dorthe Gérard
Published: March 2007

A simple, realistic model is developed to take into account kinematic effects on
laser‐induced fluorescence (LIF) measurements in crossed beam reactive scattering
experiments. The conversion factor from nascent populations to measured densities
(which are proportional to the LIF intensity) is calculated for several cases of practical
interest. The density‐flux transformation proposed by Zare and coworkers arises from
the model as a limiting case. Results concerning the C + NO → CN + O
reaction, studied in a pulsed crossed supersonic beam experiment, are also included. Calculations
carried out under various conditions emphasize the dramatic importance of beam collimation and pulse duration on detection efficiency.
Laser Induced Synthesis: Condensation of Acrylonitrile on Carvone
Authors: Stringat R. , Lemaire F. , Fellous R. , Loiseau A. M.
Published: March 2007

Laser irradiation of R(–) carvone in solution in acrylonitrile within the absorption band
of its n − π*
transition (≃350 nm) leads to the formation of cyclobutanic adducts, together with traces of camphocarvone.

The carvone transformation is complete and appears with high quantum efficiency.
The quantum yield for intermolecular reaction is intensity dependent (13–30%). This is ascribed to the fact that the reaction takes place via both a one and a two‐photon absorption channel, the second being even more efficient.
Experimental and Theoretical Analysis of Non‐linear Vibrational Relaxation of Polyatomic Molecules Strongly Excited by Resonant Laser Radiation
Authors: Carlomusto L. , Cartelli A. , Solimeno S. , Velotta R. , Bruzzese R.
Published: March 2007

We present a very simple theoretical model aimed at the analysis of non‐linear relaxation processes in
molecular gases in the presence of partial molecular dissociation induced by vibrational–vibrational
exchange between highly excited molecules. The model has a phenomenological character, since it analyzes the
behavior of a system of anharmonic diatomic molecules, which is a very rough approximation of a polyatomic
molecule such as SF6. Nonetheless, it provides an interesting key for the interpretation of a number
of peculiar features characterizing our experimental observation, with which a comparison is made. In particular,
the model takes realistic account of the influence of dissociation processes on the relaxation time.
Cyclic Ether Auxofluors on Oligophenylene Laser Dyes
Authors: Kauffman Joel M. , Kelley Charles J. , Ghiorghis Alem , Neister Edward , Armstrong Lorne
Published: March 2007

Laser dyes with terphenyl and quaterphenyl as the fluorophors and with acyclic ether auxofluors
were improved when the ether groups were made cyclic. Dyes containing cyclic ethers in 5‐ and 6‐membered
rings were observed to lase in the 360–400 nm region with better lifetime and/or solubility than their
acyclic analogs. In one case the laser output wavelength of a quaterphenyl fitted with cyclic ether auxofluors
was red‐shifted enough to match the wavelength of a sexiphenyl without auxofluors.
Comparisons of Infrared Multiple Photon Reaction Yields of Some C3–C6 Hydrocarbons
Authors: Yerram Murthy L. , Carr Robert W.
Published: March 2007

Low pressure (53 μ) infrared multiple photon decomposition of several hydrocarbons requiring large fluences to
produce measurable decomposition was investigated. Cyclopropane, propylene, methylcyclopropane,
cis‐ and trans‐2‐butene, vinylcyclopropane, cyclopentene and 1‐methylcyclopentene exhibit wide variations
in reaction product yield and the spectral dependence of yield at constant pressure and fluence. The role
vibrational state density, torsional vibrations and low intensity absorption cross section play in determining
yields was examined. The results show the complex interplay of factors affecting multiple photon decomposition.
Although the maximum observed yields tend to increase with increasing vibrational state density and absorption
cross section, they were poorly correlated with either state density or cross section. The dependence of yield upon
excitation wavenumber revealed several unexpected features which indicate that low energy vibrational level
structure must be the dominant factor in determining yields. Also, the data suggest that torsional vibrations can
ease the excitation bottleneck.
Effect of Various Anions and Zwitterions on the Lasing Properties of a Photostable Cationic Laser Dye
Authors: Kauffman Joel M. , Bentley James H.
Published: March 2007

An unusually photostable cationic laser dye first prepared by quaternization of the free base 4PyMPO (Figure 1) with methyl p‐toluenesulfonate unexpectedly had, when flashlamp pumped in methanol, half the energy output of four other N‐methyl quaternary salts: the methanesulfonate, the trifluoromethanesulfonate, the perchlorate, and the tetrafluoroborate. When four homologous zwitterions (Figure 2) prepared from
4PyMPO were tested in methanol, the output energies ranged from 1.4 to 2.5 times that of the p‐toluenesulfonate, and up to 1.3 times that of the salt with the highest output. When flashlamp pumped in water, the zwitterions showed 1.5 to 2.0 times the output energy of the p‐toluenesulfonate in water. Many of the dyes displayed laser output curves that were split in the middle, so that lasing energy appeared on either side of a dark valley. Among the zwitterions, a regular shifting from red to blue was observed as the carbon chain length was increased.
High Resolution Spectroscopy of CF3Br by Diode Laser in the Frequency Range 1070–1090 cm−1
Authors: de Bekker R. , Ebben M. , Snels M. , Stolte S.
Published: March 2007

The IR absorption spectra of gaseous CF3Br expanded in a molecular jet have been
recorded with a linewidth of about 0.002 cm−1. The rotational K‐structure of
the ν1 fundamental has been resolved and the molecular constants ΔB and
ΔA have been determined with an accuracy better than 5 x 10−6

cm−1. Spectral features belonging to the ν6‐ and ν3‐hotbands have been identified. For CF3 79Br (CF3 81Br) improved values of the vibrational origins for the fundamental ν1 = 1084.768(2) cm−1 (1084.520(2) cm−1) and for its hotbands ν3 + ν1 ← ν3 = 1081.709(80) cm−1 (1081.065(40) cm−1) and ν6 + ν1 ← ν6 = 1083.533(4) cm-1 (1083.288(4) cm-1) have been determined.
Raman spectroscopy of infrared multiphoton excited molecules
Authors: Wang Jyhpyng , Chen Kuei-Hsien , Mazur Eric
Published: March 2007

This paper presents an overview of data obtained on the intramolecular vibrational
energy distribution in infrared multiphoton excited CF2HCl, CF2Cl2, SF6 and CH3CHF2. All but CF2HCl show collisionless changes in the intensity of the spontaneous Raman signals after excitation, indicating that the excitation alters the population in the Raman active modes. A comparison of the spectrally integrated intensities of the Raman signals yields information on the distribution of vibrational energy over the modes of the molecule. The results for CF2Cl2 show a nonthermal distribution of energy after the excitation.
Interdependence of OpticalExcitation and Surface Chemistryin Laser Induced Deposition andEtching
Authors: Houle F. A.
Published: March 2007

Laser‐assisted modification of solid surfaces, e.g. thin film deposition and etching,
frequently involves a chemically reacting system whose optical and thermal properties
change continuously in time. This leads to a coupling between excitation and reaction
which has profound consequences for the cumulative effect of microscopic processes
occurring at the surface, whether thermal or photochemical in nature. An understanding
of this coupling provides an essential bridge between investigations of discrete mechanistic
steps in surface photoreactions and measurements of macroscopic rates of laser
etching and deposition. A range of situations have been found to lead to significant
interdependence between optical properties and reactivity: formation of waveguides
and gratings, chemical enhancement of absorption, coupling of optical properties and
temperature, and optical feedback in scanning. Typical examples are presented and
discussed. The real‐time effects of growth of a reflecting Ni film on an absorbing
substrate, of optical interference in the laser thermal oxidation of copper and of grating
formation in the photochemical deposition of copper are described in detail.
Infrared Induced Conformer Interconversion Processes in Low‐Temperature Matrices
Authors: Räsänen Markku , Kunttu Henrik , Murto Juhani
Published: March 2007

Molecules embedded in low‐temperature matrices experience conformer interconversion
processes due to IR‐ (or UV‐)irradiation. This paper summarizes the known
IR‐induced conformational changes, of which the majority has been studied by using
broad‐band sources provided with filters. We focus at the thermal and IR‐photochemical
methods in obtaining information of conformational energetics of matrix isolated
molecules, at the usefulness of ab initio calculations in assigning the spectra of
conformers involved and in finding the reaction path on the ground state surface. The
data obtained from a number of molecules is used to discuss possible mechanisms in both
intramolecularly hydrogen‐bonded and non‐bonded molecules. Also possible indications
of mode‐selective phenomena in these processes are dealt with. In addition,
common trends found for photorotamerization in different hosts are discussed.
Analysis of the Dynamics of theInteraction of Ultraviolet LasersWith Organic Polymers
Authors: Srinivasan R. , Sutcliffe Emile , Braren Bodil
Published: March 2007

The time‐dependent treatment of the dynamics of the ablation of polymers that was
proposed by Sutcliffe and Srinivasan has been used here to analyze the etching of several
polymers by pulsed, ultraviolet laser radiation. For five polymers which span a wide
range of absorptivities in the ultraviolet, the ablation threshold which is expressed in
terms of the “useful” photon density in the ablation volume falls within a narrow range
(±50%). The most intense absorbers show the most deviation from the average value.
The flux threshold which defines the absorbed photon level above which the photons are
useful in producing ablation is strongly influenced by the absorptivity of the polymer.
The extension of these ideas to the ablation of tissue which contains only 20% polymer is
also discussed.
Velocity Dependence ofRotationally InelasticCross‐Sections
Authors: Fell Christopher P. , McCaffery Anthony J. , Reid Katharine L. , Ticktin Anton , Whitaker Benjamin J.
Published: March 2007

Techniques are described for obtaining the energy‐dependence of state to state
rotational energy transfer (RET) cross‐sections in thermal cell experiments through
velocity selection by Doppler shift. The case of polarised excitation and detection is
discussed in detail and expressions presented which enable the state multipoles of
population, orientation and alignment to be obtained from appropriate RET experiments.
It is found that the translational order present in a non‐isotropic collision
environment, such as that resulting from excitation with a narrow linewidth laser, causes
state multipoles of different rank to become coupled. Experimental results are presented
for the energy dependence of cross‐sections for state to state transfer of
population and of orientation in Li2‐Xe collisions. The way the relative velocity vector
changes as a result of a collision may also in principle be studied using a high resolution
probe (e.g. a second laser) of the velocity spread following RET.
Two‐dimensional Imaging ofPhotofragments
Authors: Thoman John W. , Chandler David W. , Parker David H. , Janssen Maurice H. M.
Published: March 2007

The technique of photofragment imaging is described, and several examples of the
power of the technique are presented. Two‐dimensional images of state‐selected
photofragments from the photodissociations of CD3I and H2S illustrate how photofragment
imaging reveals β parameters, brancing ratios, Doppler profiles and vector
correlations. Comparisons are made with Doppler profiling and one‐dimensional
time‐of‐flight techniques.
Reactive Scattering of OxygenAtoms With Iodine Molecules
Authors: Firth N. C. , Keane N. W. , Smith D. J. , Grice R.
Published: March 2007

Reactive scattering of O atoms with I2 molecules has been studied at an initial
translational energy E~43 kJ mol−1 using cross‐correlation time‐of‐flight analysis with
resolution improved overprevious measurements. The broad centre‐of‐mass differential
cross section favours the backward hemisphere with a product translational energy
distribution lying above the distribution observed at lower initial translational energy
but below the microcannonical RRHO distribution. However, a minor component with
very low product translational energy favours the forward hemisphere. The observed
scattering is attributed to a strongly bent OII triplet complex intermediate with a lifetime
shorter than the period of overall rotation of the axis of the heavy II diatomic but long
compared with the period of vibrational and rotational motion of the light O atom.
The State‐selectedPredissociation Dynamics ofCClF2NO Ã(n,π*)
Authors: McCoustra Martin R. S. , Dyet Julie A. , Pfab Josef
Published: March 2007

The photodissociation of gaseous CClF2NO at 300 K and <20 K in a supersonic jet has
been studied in the wavelength range 568 to 705 nm of the S1(n,π*)←S0 electronic
transition. Energy disposal into, rates of formation and product‐state distributions of the
nascent NO(X2Πi) photofragment have been measured in detail, and have been
compared with statistical (Prior) calculations. The rotational population distributions of
the NO fragment are statistical up to the highest excess energies investigated, while the
spin‐orbit branching ratios are very non‐statistical and non‐thermal, favouring the lower
component. The lack of evidence for state‐specific effects in the energy disposal and
appearance times of the NO indicate that excess energy randomises prior to dissociation.
Intersystem crossing to T1 dominates the predissociation of all but the lowest S1 levels.
Levels close to the O,O origin predissociate either by internal conversion to the ground
state or by vibrational predissociation on an S1 potential energy surface that is weakly
bound in the dissociation coordinate. A bond dissociation energy of 13 700 ± 350 cm−1
(164 kJ mol−1) has been evaluated for the C—N bond.
A Simultaneous Photofragment Spectroscopy Measurement of Rovibronic and Translational Excitation in the CH3l A–Band Photodissociation System
Authors: Black John F. , Powis Ivan
Published: March 2007

The methyl iodide A‐band photodissociation is investigated using a photofragment
time‐of‐flight technique coupled with state specific detection of either the iodine atom or
methyl radical dissociation products by multiphoton ionization. The method is quite
general and allows the fragments′ velocity and spatial distributions to be determined
simultaneously with their rotational, vibrational and electronic excitation. It is shown
that methyl product from two competing dissociation channels, one direct, the other
necessitating an initial surface crossing, can be clearly distinguished by virtue of the
characteristic translational excitation in each. The different rotational excitation which
is observed in these two channels is discussed in terms of the dissociation dynamics in the
methyl iodide A‐band continuum.
Laser‐Induced‐FluorescenceSpectrum of the CNN Molecule
Authors: Curtis M. C. , Levick A. P. , Sarre P. J.
Published: March 2007

We have recorded a laser excitation spectrum of the A3Π–X3Σ− electronic band system
of the CNN radical in the gas phase, at a resolution of ca. 0.8 cm−1. The rotational branch
structure of the vibrational band near 419 nm has been simulated and molecular
parameters are obtained. The results are compared with data from laser‐induced‐fluorescence
spectra of CNN trapped in a low‐temperature matrix. A revised value for
the spin‐orbit parameter in the A3Π state is obtained and comparison is made with the
values for related molecules. The possible detection of CNN in astrophysical sources is
considered and the general features of its rotational spectrum in the ground electronic
state are described.
Rotational Relaxation ofBenzophenone in the VapourPhase
Authors: Strahand M. A. , Pearce B. , Beddard G. S.
Published: March 2007

The excited singlet state lifetimes of benzophenone vapour have been measured at
shorter wavelengths than previous studies and with picosecond time resolution.
Excitation was at a series of wavelengths from 313.5 nm to 284 nm, which gave S2(ΠΠ*)
decay times of tens of picoseconds. We also report measurements of the polarisation
anisotropy decay due to free rotation of excited state benzophenone. Time‐dependent
anisotropies calculated by both quantum mechanical and classical formulae are in good
agreement with the experimental data and demonstrate benzophenone to behave as a
rigid rotor. From the residual anisotropy, at long times, it is concluded that no rotation
to vibrational energy transfer occurs during the excited state lifetime.
Surface‐Enhanced RamanSpectroscopy ofThionine‐modified GoldElectrodes
Authors: Virdee H. R. , Hester R. E.
Published: March 2007

Surface enhanced Raman (SER) and resonance Raman (SERR) techniques have been
used in situ to investigate thionine‐modified gold electrodes. New surface roughening
procedures for gold electrodes have resulted in an order of magnitude increase in the
Raman signals. As a result of this, Raman spectra from leucothionine have been
observed for the first time. The surface Raman spectra of both thionine and leucothionine
are essentially unchanged over the pH range from 1.3 to 7 but both show major
changes at pH 10. This behaviour has been rèlated to changes in the absorption spectrum
of thionine at pH 1.0 where the compound is believed to exist as thionine hydroxide. At
pH 1.3 and 7 the Raman signals from thionine arise from a combination of surface
enhancement and resonance enhancement processes, whereas signals from leucothionine
arise solely from surface enhancement. At pH 10 surface enhancement processes
give rise to Raman intensity for both thionine and leucothionine.
A Test for Bottlenecks in theVibrational Relaxation of CH3Cland CH3Br by Ar
Authors: Beck Kenneth M. , Gordon Robert J.
Published: March 2007

The method of time‐resolved optoacoustics was used to measure the rate of vibrational
relaxation of CH3Cl(ν6) and CH3Br(ν6) by Ar. The pressure pulses generated by the
relaxing gas revealed that the rate of production of translational energy from ν6 = 1 is
approximately twice the decay rate of IR fluorescence from
ν3 = 1. No evidence was
found for a previously proposed bottleneck in rotational relaxation, which would have
resulted in an acoustic relaxation rate slower than the fluorescence decay. The faster
rates observed here can be explained qualitatively by a rapid energy release from energy levels above ν3 which precedes the IR fluorescence. A simple three‐level model,
however, is unable to explain our observations quantitatively.
Insecticidal Effects of Organotin(IV) Compounds on Plutella Xylostella (L.) Larvae. II. Inhibitory Potencies AgainstAcetylcholinesterase and Evidence for Synergism in Tests WithBacillus Thuringiensis(BER.) and Malathion
Authors: Ahmad Nazni W. , Huang Tay Siew , Balabaskaran S. , Lo K. M. , Das V. G. Kumar
Published: March 2007

Features of pesticide synergism and acetylcholinesterase (AChE) inhibition (in vitro)
were studied using a selected range of organotin compounds against the early 4th instar
larvae of a highly resistant strain of the diamondback moth (DBM), Plutella xylostella, a
major universal pest of cruciferous vegetables.

Fourteen triorganotin compounds were evaluated for their ability to enhance the
toxicity of the microbial insecticide, Bacillus thuringiensis (BT) and of the commercial insecticide,
Malathion to Plutella xylostella larvae. Supplemental synergism was observed with
triphenyl‐ and tricyclopentyltin hydroxides in combinations with Bacillus thuringiensis.
Increased synergism was observed with an increase in the number of cyclopentyl groups
on tin in the mixed series, CypnPh3-n SnX, where X = OH, and 1‐(1,2,4‐triazolyl). The
combination of (p‐chlorophenyl)diphenyltin N,N‐dimethyldithiocarbamate at LD10 and LD25
concentrations with sublethal concentrations of Malathion as well as of tricyclohexyltin
methanesulphonate at the 0.01% (w/v) concentration with Malathion exerted strong synergistic
effects (supplemental synergism) with toxicity index (T.I) values of 7.2, 19.8 and
10.1, respectively.

Studies on the in vitro inhibition of acetylcholinesterase prepared from the DBM
larvae showed that while most of the triorganotin Compounds tested were without effect on
the enzyme, compounds containing the thiocarbamylacetate or the dithiocarbamylacetate
moieties demonstrated appreciable levels of inhibition, being comparable in efficacy to
commercial grades of Malathion and Methomyl.
Transferrin: From Inorganic Biochemistry to Medicine
Authors: Messori Luigi , Kratz Felix
Published: March 2007

Transferrin is one of the key proteins of iron metabolism in mammalians. It is responsible for
the transfer of the essential iron(III) ions through the biological fluids from absorption to storage
and utilization sites. Moreover, transferrin is involved in the metabolism of other metal ions that
are either trace or toxic elements. In recent years the crystal structure of transferrin has been
solved at high resolution. This has allowed an extensive reinterpretation of the many
spectroscopic studies carried out on this protein in the last decade as well as the elucidation of
some interesting structure‐function relationships. We review here recent progresses in
transferrin biochemistry, particular focus being given to those aspects that are relevant from a
medical point of view.
Protein‐binding Properties of two Antitumour Ru(III) Complexes toHuman Apotransferrin and Apolactoferrin
Authors: Kratz F. , Keppler B. K. , Messori L. , Smith C. , Baker E. N.
Published: March 2007

The interaction of two ruthenium(III) complexes exhibiting high anticancer activity ‐ namely trans‐Indazolium(bisindazole) tetrachlororuthenate(III), Hlnd[RuInd2Cl4], and trans‐Imidazolium (bisimidazole)
tetrachlororuthenate(III), Hlm[RuIm2Cl4], ‐ with human serum apotransferrin has been
investigated through spectroscopic and chromatographic techniques with the ultimate goal of
preparing adducts with good selectivity for cancer cells due to the fact that tumour cells express
high amounts of transferrin receptors on their cell surface.
Whereas the binding of Hlm[RuIm2Cl4] to human serum apotransferrin takes several hours,
Hlnd[RuInd2Cl4], the less toxic complex, gives rise to a well defined 2:1 complex within a few
minutes. Hlnd[RuInd2Cl4] will react with apotransferrin only in the presence of bicarbonate, this
anion dictating the kinetic and mechanistic characteristics of protein‐binding.
Circular dichroism studies had previously indicated that binding of both Ru(III) complexes occurs
around the unoccupied iron(III) binding sites; this result is now confirmed by preliminary X‐ray
data of Hlnd[RuInd2Cl4] and Hlm[RuIm2Cl4] bound to apolactoferrin, a related iron protein. The
crystallograhic data reveals that binding of both complexes takes place at histidine residues, and
that the ligand (indazole) remains bound in the case of Hlnd[RuInd2Cl4].
Analysis of Multidrug Transporter in Living Cells. Inhibition ofP‐glycoprotein‐mediated Efflux of Anthracyclines by Ionophores
Authors: Borrel Marie-Nicole , Pereira Elene , Fiallo Marina , Garnier-Suillerot Arlette
Published: March 2007

One of the major obstacles of chemotherapy is that, after repeated treatments, cellular
resistance to the drug appears. The problem is that the tumor cells become resistant not only to the
drugs which have been used during the treatment but also to other drugs which are structurally and
functionally unrelated. This is termed ‘multidrug resistance’ (MDR). MDR is frequently associated
with decreased drug accumulation resulting from enhanced drug efflux. This is correlated with the
presence of a membrane protein, P‐glycoprotein, which pumps a wide variety of drugs out of cells
thus reducing their toxicity. The search for molecules able to reverse MDR is very important. We
here report that mobile ionophores such as valinomycin, nonactin, nigericin, monensin, calcimycin,
lasalocid inhibit the efflux of anthracycline by P‐glycoprotein whereas, channel‐forming ionophores
such as gramicidin do not. Cyclosporin which is also a strong Ca2+ chelating agent also inhibits the
P‐glycoprotein‐mediated efflux of anthracycline.
Chelating Tendencies of Bioactive Aminophosphonates
Authors: Kiss Tamas , Lázár István , Kafarski Pawel
Published: March 2007

The metal‐binding abilities of a wide variety of bioactive aminophosphonates, from the
simple aminoethanephosphonic acids to the rather large macrocyclic polyaza derivatives, are
discussed with special emphasis on a comparison of the analogous carboxylic acid and
phosphonic acid systems. Examples are given of the biological importance of metal
ion – aminophosphonate interactions in living systems, and also of their actual and potential
applicability in medicine.
2D NMR Methods for Structural Delineation of Copper(II) Complexesof Penicillin and Pilocarpine
Authors: Gaggelli Elena , Gaggelli Nicola , Valensin Gianni
Published: March 2007

A method was developed for delineating the structure of
paramagnetic metal complexes. The selective disappearance
of cross‐peaks in proton‐carbon shift correlated 2D NMR
maps was shown to uniquely depend upon the scalar and/or
dipolar interaction between ligand nuclei and the unpaired
electron(s), thus providing a means of identifying binding
sites. Copper(II) was shown to form metal complexes with
both Penicillin (PNC) and Pilocarpine (PLC) and the structure
of the two 1:2 complexes in water solution at physiological
pH were determined.
In Vitro Antitumour Activity of Some Triorganophosphinegold(I)Thionucleobases
Authors: Tiekink Edward R. T. , Cookson Peter D. , Linahan Bernadette M. , Webster Lorraine K.
Published: March 2007

A series of phosphinegold(I) thionucleobase analogues, [R3PAu(SRx)] (R = Et, Ph or chexyl; HSR1 = 2‐mercaptobenzoic acid, HSR2 = 2‐thiouracil, HSR3 = 6‐mercaptopurine
and HSR4 = 6‐thioguanine) have been examined for their in vitro cytotoxicity in L1210
murine leukemia cells in culture. The range of ID50 values (continuous 48 h exposure) for
the complexes is 0.041 ‐ 0.131 μM. The complexes with SR3 and SR4 are generally the
most active; however, there is no clear trend associated with the phosphine ligands.
Synthesis of the Sulphonate and Phosphonate Derivatives ofMercaptoacetyltriglycine. X‐Ray Crystal Structure of Na2[ReO(Mercaptoacetylglycylglycylaminomethanesulphonate)]·3H2O
Authors: Hansen Lory , Taylor Andrew , Marzilli Luigi G.
Published: March 2007

Mercaptoacetyltriglycine forms complexes with  186/188Re and  99mTc radionuclides that are useful
in nuclear medicine because they are substrates of the renal anion transport system. However,
the renal clearance of (MAG3 = penta‐anionic form of mercaptoacetyltriglycine, M =
Re, Tc) complexes are less than ideal. Organic sulphonates are also transported by the renal
anion transport system and phosphonates are similar to sulphonates in size and shape. In an
effort to develop new ligands that form Re and Tc complexes and have improved renal clearances
compared to complexes, the sulphonate and phosphonate derivatives of
mercaptoacetyltriglycine were synthesized. The dianion (MAG2‐AMS =
penta‐anionic form of mercaptoacetylglycylglycylaminomethanesulphonic acid) was prepared for
characterization by exchange reaction of ReOCl3(Me2S)(OPPh3) and isolated as the disodium
salt. The structure of Na2[ReO(MAG2‐AMS)] · 3H2O (6) was determined by X‐ray diffraction. The
coordination geometry is pseudo square pyramidal, with the nitrogen and sulfur donor atoms
forming a square base and the oxo ligand at the apex. The deprotonated sulphonate group has a
syn conformation with respect to the oxo ligand. The renal clearances of
and were similar in rats and suggest that the difference in total charge
between the and groups is not important to renal clearance. However, their renal
clearances were 40‐50% less than that of suggesting that the size and shape
of the large tetrahedral and groups of and inhibit recognition by the renal transport system compared to the small planar group
of .
Contribution of H‐Bonding to the Preference of PlatinumAnti‐Tumour Drugs for Particular Bases and Particular Cross‐Links
Authors: Natile Giovanni
Published: March 2007

The stereochemical factors that influence the tendencies for sequence specific binding of
platinum antitumour drugs to DNA are examined. The NHs of the platinum‐amine moiety
can form hydrogen bonds to the O6 of guanine or to a phosphate oxygen of DNA. Modelling
the stereochemistry of the NH atoms can lead to compounds with a strong preference for
forming one type of adduct with DNA.
Preparation and Crystal Structure of a Platinum(II) Complex of[CH2N(CH2COOH)CH2CONH2]2, the Hydrolysis Product of an Anti‐TumourBis(3,5‐Dioxopiperazin‐1‐YL)Alkane
Authors: Nolan Kevin B. , Ryan Leo P. , Campbell Colm J. , McArdle Patrick , Cunningham Desmond , Higgins Tim
Published: March 2007

The synthesis and crystal and molecular structures of the platinum(II) complex
Pt(HL)Cl where H2L is the diacid diamide –, a
hydrolytic metabolite of an antitumour active bis(3,5‐dioxopiperazin‐1‐yl)alkane are
reported. The complex is square planar and contains HL− as a tridentate 2N (amino),
O (carboxylate) donor. The metal to ligand bond distances are Pt‐Cl 2.287(1) Å, Pt‐O
2.002 (1) Å, Pt‐Ntrans Cl 2.014(1) Å and Pt‐Ntrans O 2.073 Å. There is extensive
hydrogen bonding, each molecule of Pt(HL)Cl being intermolecularly hydrogen
bonded to ten others giving a 3‐dimensional network. There is also one
intramolecular H‐bond.
Redox Chemistry and [Au (CN)2 -] in the Formation of Gold Metabolites
Authors: Shaw G. Frank , Schraa Sabine , Gleichmann Ernst , Grover Yash Paul , Dunemann Lothar , Jagarlamudi Annapurna
Published: March 2007

The role of hypochlorite ion, which can be generated by the enzyme myleoperoxidase, in
the biochemistry of gold(I) anti‐arthritic drugs was investigated. Sodium hypochlorite (OCl−)
directly and rapidly oxidizes AuSTm, , AuSTg (gold thioglucose) and auranofin
(Et3PAuSATg). The resulting gold(III) species were detected by an Ion Chromotography Ion‐Pairing
technique that was developed to distinguish gold(I) and gold(III). Formation of Au(III) was also
demonstrated spectrophotometrically after the conversion to . The reactions of AuSTm,
AuSTg, and auranofin are complex and gold(III) appears only after the initial oxidation of the thiolate
(and phosphine) ligands.

The enzymatic reaction, using MPO with H2O2 and Cl− as substrates, leads to slow
oxidation of , AuSTm or AuSTg. The extent and rate of reaction depend on the
concentrations of MPO, H2O2, and Au(I). The continued presence of Au(I) during the initial stages
of reaction (oxidation of the thiolates in AuSTm and AuSTg) and the conversion to Au(III) in the
latter stages of the reaction were demonstrated.

, a gold metabolite, binds tightly to serum albumin. Unlike other gold(I)
complexes, aurocyanide reacts almost negligibly at Cys‐34 via ligand exchange. Instead, there is
a strong association (K1 = 5.5 × 104 and K2 = 7.0 × 103; n1 = 0.8 and n2 = 3) of intact .
The full extent of binding is revealed only by equilibrium methods such as NMR or ultrafiltration; the
bound gold dissociates extensively on conventional gel‐exclusion columns and partially on
Penefesky spun columns.

The immunological and pharmacological significance of these results are discussed.