bluuebunny/crossref_metadata_2025 huggingface dataset:
Time‐Resolved Investigation of the Molecular Chemiluminescence SrI(A2∏1/2,3,2,B2∑+→X2∑+) and the AtomicResonance Fluorescence Sr(53P1→51S0) Following The Pulsed Dye LaserGeneration Of Sr(53PJ) in the Presence of CF3I
Authors: Antrobus S. , Husain D. , Lei Jie , Castaño F. , Rayo M. N. Sanchez
Published: September 2007

A time‐resolved investigation is presented of the electronic energy distribution in SrI following the
collision of the optically metastable strontium atom, Sr [5s5p(3PJ)], with the molecule CF3I. Sr[5s5p(3PJ)], 1.807 eV above its 5s2(1S0) electronic ground state, was generated by pulsed dye‐laser excitation of ground
state strontium vapour to the Sr(53P1) state at , λ =689.3 nm {Sr(53P1←51S0)} at elevated temperature (840 K) in the presence of excess helium buffer gas in which rapid Boltzmann equilibration within the 53PJ spin‐orbit
manifold takes place. Time resolved atomic emission from Sr(53P1→51S0) at the resonance transition
and the molecular chemiluminescence from SrI(A2∏1,2,3/2,B2∑+→X2∑+) resulting from reaction of the excited
atom with CF3I were recorded and shown to be exponential in character. SrI in the A2∏1/2,3/2 (172.5, 175.4 kJ mol-1) and B2∑+ (177.3 kJ mol-1) states are energetically accessible on collision by direct‐I‐atomic
abstraction between Sr(3P) and CF3I. The first‐order decay coefficients for the atomic and molecular emissions are found to be equal under identical conditions and hence SrI(A2∏1/2,3/2, B2∑+) are shown to arise from direct I‐ atom abstraction reactions. The molecular systems recorded were SrI (A2∏1/2→X2∑+, Δv=0, λ=694 nm), SrI(A2∏3/2→X2∑+, Δv=0, λ=677 nm) and SrI(B2∑+→X2∑+) (Δv=0, λ=674 nm), dominated
by the Δv=0 sequences on account of Franck‐Condon considerations. The combination of integrated
m61ecular and atomic intensity measurements yields estimates of the branching ratios into the specific electronic
states, A1/2, A3/2 and B, arising from Sr(53PJ)+CF3I which are found to be as follows: A1/2,1.2 × 10-2; A3/2, 6.7 × 10-3; B, 5.1 × 10-3 yielding ∑SrI(A1/2+A3/2+B)=2.4 × 10-2. As only the X, A and B states SrI are accessible on reaction, assuming that the removal of Sr(53PJ) occurs totally by chemical removal, this yields an upper limit for the branching ratio into the ground state of ca. 98%. The present results are compared with previous time‐resolved measurements on excited states of strontium halides that we have reported on
various halogenated species resulting from reactions of Sr(53PJ), together with analogous chemiluminescence studies on Sr(3PJ) and Ca(43PJ) from molecular beam measurements.
High‐Resolution Non‐Resonant Two‐Photon Threshold Photoionization of Propyne
Authors: Matsui Hiroshi , Zhu Yi-Fei , Grant Edward R.
Published: September 2007

Using techniques of delayed pulsed‐field ionization zero‐kinetic‐energy (ZEKE) photoelectron spectroscopy,
we have resolved spin‐orbit structure in the rotational profile of the origin band in the non‐resonant
two‐photon threshold photoionization of propyne. Both the rotational and spin‐orbit characteristics of this
band are well‐simulated by a simple model that assumes the spin‐orbit splitting of acetylene cation in
combination with the rotational constants of the neutral propyne ground state. This result, combined with
very little evidence for photoionizing transitions terminating on vibronically excited states, suggests that the
structure of the propyne cation structure is very close to that of the neutral ground state and very little altered
by Jahn‐Teller distortion.
Inhibition Effect on Molecular Weight Distribution GeneratedUnder Free Radical Polymerization by Laser Pulses
Authors: Evseev A. V. , Nikitin A. N.
Published: September 2007

Molecular weight distributions (MWDs) under free radical polymerization initiation by an arbitrary
sequence of radiation pulses have been investigated. Analytical expressions enabling to account for influence
of the polymer chains linear termination (for example, inhibition) have been obtained. On the basis of these
expressions the MWDs generated by pulse‐periodic radiation have been investigated theoretically. The
calculated MWDs for polymerization in the presence of high concentration of retarder have been given and
the influence of the inhibitor burning within the irradiation process on the MWDs character have been
studied. It has been shown that possibility to employ the PLP method for determination of polymerization
rate constant (kp) depends significantly on the efficiency ofchains linear termination: the PLP method can be
confidently used at τ > T (where τ is the effective lifetime of growing radicals, T is the pulse irradiation period)
and it is doubtful if τ < T/3. The expression for specifying of pulses number required for establishment of
pseudostationary polymerization has been obtained for the polymerization at high concentration of retarder.
The calculated MWDs for polymerization of MMA are presented.
Multiphoton Dissociation of Phenylsilane Upon Excitation at 212.5 NM
Authors: Oujja Mohamed , Martín Margarita , De Nalda Rebeca , Castillejo Marta
Published: September 2007

The photodissociation processes that follow the photolysis of phenylsilane with a narrow band laser at
212.5 nm were studied by observing photofragment fluorescence spectra in the 200 to 900 nm range.
Emission from several excited states of Si atoms was detected together with emissions from the molecular
fragments SiH(A2∆) and C2(d3∏g). Si and SiH emissions show a quadratic dependence with laser energy whereas dependence for C2 emission is cubic, indicating the participation of two and three photon processes in the formation of the respective fragments. The emission spectra of the molecular fragments
provides information about their internal energy content and allows discussion of the possible channels
responsible for the appearance of those fragments.
Quantum Beats in Transient Spectroscopy of J‐Aggregates
Authors: Glaeske H. , Feller K.-H. , Gaišaukas E. , Knöll L.
Published: September 2007

Quantum beats in transient absorption of PIC‐J‐aggregates, modelled by a modified 3‐level‐system are
calculated. Experimental conditions for the possibility of their observation are investigated. The influence
of the temperature dependent phase relaxation on the temporal evolution of quantum beat signals is
considered.
Femtosecond Transient Absorption Microspectroscopy of Benzil ConfinedInto a Single Bead of Porous Glass
Authors: Porter Christopher F. , Tamai Naoto , Masuhara Hiroshi
Published: September 2007

The photophysical properties of benzil dissolved in free solution and in solution confined into a single
bead of porous glasses (size < 100 μm) were investigated by femtosecond transient absorption microspectroscopy.
In nonpolar solvent, cyclohexane, the rate of conformational change from the skewed to the
near trans‐planar form was reduced from 2.2 × 1012s-1 in free solution to 9.1 × 1011s-1 in porous glasses with an average pore diameter of 26 nm. In polar solvent, DMF, however, there was little
difference between the two systems.
Non‐linear Simultaneous Two‐Photon Excitation Energy Transfer inthe Wrong Direction
Authors: Nickoleit M. , Uhl A. , Bendig J.
Published: September 2007

The simultaneous two‐photon excitation energy transfer (SEET) was demonstrated for
the first time using trichromophoric model compounds. Two identical donors (A–antenna)
were covalently linked to an energy acceptor unit (T–target) with different
energy levels preventing energy transfer of a single photon. At high intensity illumination
(laser exposure) of a trichromophoric system A∼T∼A (A–fluorescein, erythrosin; T‐Estilbene),
sufficient to excite both of the appended donor subunits, population of the
target excited state may occur via simultaneous energy transfer of two photons, one from
each donor. In order to restrict reverse energy transfer from the higher energy target to
the lower energy donor(s) it is necessary that the excited target unit undergoes an
efficient photoreaction. In the investigated case this was achieved by photoisomerization
of the stilbene unit used for monitoring of the SEET.
Dispersion of Third Order Optical Nonlinearity of PseudoisocyanineJ‐Aggregates
Authors: Gadonas R. , Pugzlys A. , Feller K.-H.
Published: September 2007

Dispersion of degenerate four‐wave mixing (DFWM) efficiency near the exciton resonance
of aggregates of 1,1′‐diethy1‐2‐2′‐cyanine (pseudoisocyanine, PIC) chloride is reported.
Correlation with the spectrum of imaginary parts of nonlinearity obtained by pump and
probe techniques is discussed. Third order nonlinear susceptibility of PIC aggregates
has been calculated supposing highest density packing attainable by Langmuir‐Blodgett
technique. The nonlinear figure‐of‐merit of aggregates was evaluated, which is intensity
dependent due to exciton annihilation. Observed intensity and wavelength dependence
of mixing efficiency is qualitatively explained in terms of absorption saturation, exciton
annihilation, and subsequent generation of an excess diagonal disorder by vibrational
energy accumulated in aggregates.
A Comparative Study of theUV Laser Ablation of Van Der Waals Films of Benzene Derivatives
Authors: Georgiou S. , Koubenakis A. , Kontoleta P. , Syrrou M.
Published: September 2007

Ablation of thick (≈ 15 μm) films of C6H6, C6H5CH3 and C6H5CI at 248 nm and 193 nm
is studied by means of time‐of‐flight quadrupole mass spectrometry. The dependence of
the desorbate most probable translational energies on laser fluence is determined over the
≈20–200 mJ/cm2 range. In all cases, the corresponding diagrams are found to exhibit
“plateaus”, in accord with the report by Braun and Hess [J. Chem. Phys. 99 (1993) 8330].
However, no specific correlation with the thermodynamic properties of the compounds is
observed, thereby questioning the attribution of the “plateaus” to phase transformation
of the films under ablation conditions. A high sensitivity of the distributions and intensities
on the rate of deposition and the irradiation history of the films is observed,
indicating the importance of the matrix “structure” for the distribution of the absorbed
energy. On the other hand, the analysis of the total translational energies of the desorbates
suggests that during ablation, efficient energy transfer occurs in the film. This
possibility is further demonstrated by the observation of high translational energies and
sputtering yields for C6H12(nonabsorbing at 248 nm) condensed in thickness of ≈ I μm
on top of C6H5CH3 films. These observations can be qualitatively explained in terms of
the collisional sequence model. Alternatively, a photothermal model may be applicable
under the provision that energy distribution in the films is limited due to imperfections
introducing barriers (bottlenecks) to its ‘flow’.
Single Photon IonisationMass Spectrometry Using Laser‐Generated Vacuum Ultraviolet Photons
Authors: Lockyer Nicholas P. , Vickerman John C.
Published: September 2007

This paper provides an overview of the method of single photon ionisation mass
spectrometry. A review of the theory of frequency upconversion using third‐order 4‐
wave sum mixing in isotropic media and experimental results of third harmonic
generation (THG) using a frequency tripled 355 nm Nd:YAG pump source are
presented. Vacuum Ultra‐violet (VUV) photons of wavelength 118 nm are detected in an
acetone ionisation chamber. The emphasis of this paper is on the practical aspects of
generating and detecting the VUV photons and using them for single photon ionisation
(SPI) in the ion source of a mass spectrometer. Optimum gas pressures for THG in Xe
and Xe/Ar mixtures are established. For a pump beam of well defined mode structure the
optimum gas pressures are in excellent agreement with theory. The major loss
mechanism is attributed to re‐absorption of VUV by the tripling gas. SPI mass spectra
of hexane and the biomolecule valyl‐valine are presented illustrating the power of the
technique.
Two‐Color Two‐Photon Ionization Spectrum of Pyrene in N‐Hexane
Authors: Nakashima Keiji , Soga Hirofumi , Ogawa Teiichiro
Published: September 2007

The photoionization process of pyrene in non‐polar solvent has been investigated using a
two‐color two‐photon ionization technique. The ionization spectrum near threshold of
pyrene in n‐hexane was measured by a delayed
irradiation of a dye laser 20 ns after an N2
laser at total excitation energies of 5.9–6.22 eV. The two‐photon ionization threshold of
pyrene was in the vicinity of 5.9 eV which is larger by 0.7 eV than that expected from the
onset of one‐photon ionization. The ionization spectrum shows maxima at 5.92 and 5.99
eV which may be assigned to an autoionization process.
Laser‐Induced Photochemical Reaction of Maleic Acid Solutions inthe Presence of Hydrogen Peroxide
Authors: Shimizu Yuichi , Sugimoto Shun′ichi , Kawanishi Shunichi , Suzuki Nobutake
Published: September 2007

Targeting the selective and direct synthesis of tartaric acid (TA), the photochemical
reactions of maleic acid (MA) solutions containing H2O2. in various solvents have been
investigated using four wavelengths in the UV region between 193 and 351 nm, with high
intensity from an excimer laser. All the laser irradiations in H2O resulted in the direct
synthesis of TA with lower selectivity and it was found that, with XeF‐laser (351 nm)
irradiation in 1,4‐dioxane, TA is selectively and directly synthesized from MA containing
H2O2 of lower concentration at room temperature. On the other hand, none of the
irradiations in methanol, N,N‐dimethylformamide, acetonitrile, and tetrahydrofuran
gave the selective formation of TA. On the basis of these results, the reaction scheme for
the selective formation of TA is discussed.
High Resolution Spectroscopy With Molecular Beams and Tunable Lasers
Authors: Vetter R. , Luc P. , Amiot C.
Published: September 2007

High resolution Doppler‐free laser techniques are used in beam experiments to improve
the spectroscopic description of complex diatomic molecules. The case of TiO is
considered here for its implication in reaction dynamics studies and its interest in
Astrophysics. Two absorption bands in the visible have been analyzed:
B3Π − X3 Δ(1 − 0) and c1Φ − a1 Δ(0 − 0). Owing to accurate wavenumber measurements,
it has been possible to extend the analysis to high rotational quantum numbers
and to carry out detailed spectroscopic calculations. They show that a careful revisiting
of the TiO electronic structure is necessary.
Nanosecond Versus, Picosecond Molecular Multiphoton Fragmentation of Keteneand Cyclohexane
Authors: Castillejo M. , Martín M. , de Nalda R.
Published: September 2007

Multiphoton dissociation of ketene was studied at 290.5 nm after irradiation of the first
excited singlet state with two different laser pulsewidths of 4 ns and 10 ps. Analysis of the
photofragment fluorescence spectra in the two time domains sheds light on the
mechanisms that are responsible for the production of the observed CH(A2Δ),  (B2Σ−)
and C2(d3Πg) photofragments. Multiphoton ionization of cyclohexane induced by a
visible laser at 581 nm and its second harmonic at 290.5 nm was measured in the above
mentioned pulse duration regimes. Study of the dependence of the total ionization signal
on pressure and laser energy helps to clarify the role played by the giant resonance of this
molecule at 84000 cm-1 in the photoionization process.
Carbon Isotope Selective Separation From MPD of CF3Br With a TEA CO2 Laser
Authors: del Barrio J. I. , Cézar R. Fernández , G.- Tablas F. M.
Published: September 2007

Pure CF3Br and mixtures of this substance with monoatomic (He, Ar and Xe),
homonuclear diatomic (H2, D2, N2), polyatomic gases (CF4) and NO have been
irradiated with a TEA CO2 laser. Carbon‐13 enrichment factor and carbon‐13 selectivity
have been estimated from the mass spectrometric analysis of the undissociated CF3Br as
a function of excitation wavelength, fluence, temperature and pressure. The irradiating
wavelength is a crucial parameter to achieve enrichment. The nature of the added gas
also affects considerably selectivity. Best enrichment is achieved in mixtures with NO due
to its radical‐like character.
Photofragmentation of Cl2 at 308 nm
Authors: Samartzis Peter C. , Gougousi Theodosia , Kitsopoulos Theofanis N.
Published: September 2007

The velocity distributions for the Cl(2P3/2) and Cl(2P1/2) photofragments produced by the
photolysis of Cl2 at 308 nm are measured using ion imaging. The angular distributions
yield anisotropy parameters of β(2P3/2) = −1.00 ± 0.05, β(2P1/2) = −0.95 ± 0.05, suggesting
that Cl(2P3/2) and Cl(2P1/2) is essentially produced via non‐adiabatic curve crossing between
the lu and the excited electronic states.
Single Pulse Carbon‐13 Enrichment of CF3 Under IR MPD in A ShortGas Dynamic Flow
Authors: Makarov G. N. , Malinovsky D. E. , Ogurok D. D.
Published: September 2007

An experimental approach is described for obtaining highly enriched residual gas under
IR multiphoton dissociation (MPD) of molecules in one cycle of irradiation. The
approach is based on utilization of a pulsed molecular flow of small length (Δxfl ≤ 1cm).
The use of a short flow length leads to high values of the dissociation yield of molecules
(β≃1) in the whole volume of the flow. Owing to this, high enrichment of the residual
gas is achieved in one cycle of irradiation. The isotopically‐selective dissociation of CF3I+
in the pulsed gasdynamic flow of a small length was studied. About 400‐fold enrichment
of the 13C isotope in the residual gas was obtained following irradiation of a molecular
flow of CF3I of natural isotope composition by a single laser pulse. The selectivity of
dissociation was measured to be α ≥ 10
Hydrophobicity of Water at the Surface as Studied by laser‐InducedFluorescence Microscopy
Authors: Li Yao-qun , Sasaki Shinya , Inoue Takanori , Ogawa Teiichiro
Published: September 2007

A sensitive comparative fluorescence microscopic approach was developed and used to
study the water at the air‐water interface region. An insoluble chromophore mesoc‐α,β,γ,δ‐tetraphenylporphine (TPP) was spread on the water. Its fluorescence spectrum
indicated that the spectrum of TPP on the water surface was similar to those measured in
nonpolar hydrocarbon solvents. Thus, the water at the surface was concluded to be
hydrophobic and less polar than the water in the bulk.
The Role of Electric Fields and Ion Concentrations in the Formation and Stabilization of High‐nRydberg States
Authors: Held A. , Schlag E. W.
Published: September 2007

ZEro Kinetic Energy (ZEKE) spectroscopy relies on electrons produced through delayed
field ionization of the narrow band of high‐n Rydberg states which exist just below the
ionization limit of each ionic eigenstate. Using the unique properties of these weakly
bound, stable, high‐n Rydberg states (ZEKE states) below the ionization limit rather
than the unbound states above the limit, as in PES, leads to an improvement in
resolution of more than two orders of magnitude. Several different types of ZEKE
experiments, each designed to probe the formation and stability of these states, are
presented here. These experiments were performed with pulsed and static electric fields of
different magnitude and duration at different ion concentrations. The results indicate an
enhanced ZEKE state decay with increasing electric field strengths and an enhanced
formation and stabilization with increasing ion concentrations. A strong interplay
between field strength and ion concentration ZEKE state formation is demonstrated.
The strong influence of electric fields and ion concentrations on the physical properties
of the ZEKE state, above and below the classical ionization threshold, is also
demonstrated through late time (tens of microseconds) decay rate measurements.
Study of Agricultural Samples by Laser Desorption Coupled With Resonance‐Enhanced MultiphotonIonization and Time‐of‐Flight Mass Spectrometry: Application to Carbendazim Analysis in Pepper
Authors: Bescós B. , Orea J. M. , Montero C. , Ureña A. González , Valverde A. , Aguilera A.
Published: September 2007

A method for the analysis of carbendazim in peper has been developed using
Supercritical Fluid Extraction (SFE) for the sample preparation and the combination
of Laser Desorption (LD) with Resonance Enhanced Multi‐Photon Ionization (REMPI)
coupled to Time‐of‐Flight Mass Spectrometry (TOF‐MS) for the detection. The method
allows the analysis of carbendazim in pepper reducing the sample preparation step and
avoiding the matrix effects present in classical GC and HPLC techniques, as well as the
problems related to the labile properties of carbendazim. The detection limit obtained is
of the same order of magnitude as the generally employed HPLC technique, but with
higher sensitivity and easier sample preparation.
Photodissociation of Ozone at 248 nm and Vacuum UltravioletLaser‐Induced Fluorescence Detection of O(1D)
Authors: Chowdhury A. M. Sarwaruddin
Published: September 2007

Ozone molecules, O3, were photodissociated in the presence of N2 at 248 nm (KrF laser)
to O(1D)+ O2(1∆). The O(1D) atoms were detected by generating vacuum ultraviolet
laser‐induced fluorescence (VUV LIF) for the 3s1D0 ‐2p 1D transition at 115.2 nm. The
115.2 nm probe laser was generated by frequency tripling (ω vuv=3ω) of the 345.6 nm
PTP dye laser in a Xe gas cell.
Kinetic Study of the Reaction of Rh(a4F9/2) with N2O, O2 and NO
Authors: Campbell Mark L.
Published: September 2007

The gas phase reactivity of Rh(a4F9/2) with N2O, O2 and NO is reported. Removal rate
constants for the excited states of rhodium below 13,000cm-1 are also reported. The
reaction rate of Rh(a4F9/2) with N2O is relatively temperature insensitive. The rate
constants for the bimolecular reaction are described in Arrhenius form by
(1.3 ± 0.3) × 10−12exp⁡(−1.3 ± 0.8KJ/mol/RT)cm3s−1 The reaction rates of the a4F9/2
state with O2 and NO are pressure dependent. For O2, the limiting low‐pressure thirdorder,
K0, and limiting high‐pressure second‐order, K∞, room temperature rate constants in
argon buffer are (6.6 ± 0.6) × 10−30cm6s−1 and (2.1 ± 0.2) × 10−11cm3s−1, respectively.
For NO, K2 and K∞ are (1.3 ± 0.2 × 10−30cm6s−1) and (2.1 ± 0.4) × 10−11cm3s−1,
respectively. The removal rates of the excited states are faster than the ground state by a
factor of 2 or more.
Pump‐ And Probe‐WavelengthDependencies of PicosecondAnti‐Stokes Raman Spectrumof Trans‐Stilbene in the S1 State
Authors: Nakabayashi Takakazu , Okamoto Hiromi , Tasumi Mitsuo
Published: September 2007

Vibrational relaxation dynamics of trans‐stilbene in the S1 state immediately after
photoexcitation is studied by picosecond time‐resolved anti‐Stokes Raman spectroscopy
with several pump and probe wavelengths. Pump‐wavelength dependence of the anti‐
Stokes spectrum indicates that, when pump photons with high excess energy
(≈5200cm-1) are used, the anti‐Stokes Raman bands at 0 ps delay time arise from
vibrationally excited transients with excess vibrational energy not thermally distributed
in the molecule. Probe‐wavelength dependence suggests that the vibrationally excited
transients at 0 ps are mostly on the lowest excited vibrational levels, as far as the olefinic
C═C stretching and the C–Ph stretching modes are concerned. The vibrational
relaxation process of S1trans‐stilbene is discussed on the basis of the observed results.
Transient Absorption Spectra ofVibrationally Excited WaterMolecule on Zeolite Surface
Authors: Fujino Tatsuya , Wada Akihide , Kano Satoru S. , Domen Kazunari , Hirose Chiaki
Published: September 2007

By means of infrared pump‐probe technique, spectroscopic feature of vibrationally
excited water molecule (D2O) on mordenite zeolite (OD) has been investigated.
Populational lifetime of the OD stretching band (ν3:2730cm-1) was determined to be
43±5 ps at 123 K by the time evolution of hot band. The transient bleachings and
absorptions appeared when the D2O molecule was promoted to the vibrationally excited
level of the OD stretching modes. Especially, the transient absorption at 2680 cm-1 has
rapid decay time (≈15 ps) and it was assigned as the overtone between ν3 mode and
vibrationally excited ν1 mode (2620 cm-1).
Time‐Resolved Resonance RamanStudy of Biphenyl Occluded in theSupercages of Faujasitic Zeolites
Authors: Buntinx G. , Ginestet G. , Gener I. , Coustillier G. , Brémard C.
Published: September 2007

The laser photolysis (248 nm, 20 ns) of biphenyl (BP, S0) occluded in the void space of
faujasitic zeolites (NanFAU)
,
with n=0, 56, 85 has been studied
by time‐resolved resonance Raman spectroscopy combined with time‐resolved diffuse
reflectance UV‐visible absorption spectroscopy in the ns–μs time scale. The excitation
(370 nm, 8 ns) of the RR scattering in the wavelength region of the UV electronic
absorption of the transient species provides clear evidence of the radical cation (BP+) as
major species for zeolites NanFAU (n=56, 85). The amount of triplet state (BP, T1)
depends on the aluminum content and in a less extent on the fluence of the pump laser at
the sample.
Temporally Two‐DimensionalFifth‐Order Raman Scatteringon Intermolecular Vibrationsin Cs2/Pentane Binary Mixtures
Authors: Steffen Thomas , Nakashima Satoru , Duppen Koos
Published: September 2007

Third‐ and fifth‐order impulsive stimulated Raman scattering experiments are performed
to study low‐frequency intermolecular vibrations in CS2/pentane binary mixtures. The
changes of the optical Kerr effect response cannot be assigned unequivocally to a single
microscopic process. In particular, the homogeneous and inhomogeneous line broadening
mechanisms cannot be determined. Temporally two‐dimensional Raman scattering
experiments indicate that the correlation time of fluctuations of the intermolecular
potential decreases upon dilution. The experimental results give evidence of strong
coupling between the ultrafast coherent vibrations and the slow reorientational diffusion.
Infrared Spectroscopy of EnzymeReaction Intermediates
Authors: Wharton C. W. , Page M. G. P. , Chittock R. S. , Regan T. E. , Ward S.
Published: September 2007

The serine proteinase mechanism has been studied using a wide range of techniques over
many years and is now well understood in terms of the formal chemical changes that
occur on the reaction pathway. At the atomic level our understanding is less secure in
that available techniques are unable to define interactions such as hydrogen bonding
with sufficient accuracy. Atomic interaction is strongly dependent upon separation
distances and these need to be measured either directly or indirectly in the dynamic
reacting system. Infrared spectroscopy has been applied to the study of chymotrypsin
acylenzyme reaction intermediates with the aim of measuring, albeit indirectly, the
strength of hydrogen bonding in the oxyanion hole catalytic device. These measurements
have been successful with moderately specific substrates but there is a long way to go in
terms of improved time‐resolution. It is tentatively proposed that tetrahedral
intermediates accumulate at high pH. This is, we believe, the first report of the relatively
direct observation of this phenomenon in any reacting ester system, chemical or enzymic.
The approach used with the serine proteinases has been applied to studies of the
transpeptidase of Streptococcus pneumoniae
PBP2x. We have shown that the acylenzyme
formed from benzylpenicillin hydrogen bonds most strongly in the oxyanion hole. This
bonding, in contrast to serine proteinases and β‐lactamases where the interaction
facilitates catalysis, serves to stabilise the ester intermediate as required for effective
antibiotic action. We see this as a good example of ‘Nature knows Best’ since semisynthetic
antibiotics, designed to be resistant to hydrolysis by β‐lactamases, hydrogen
bond more weakly and the acylenzymes hydrolyse more rapidly.
Picosecond Anti‐Stokes RamanExcitation Profiles as a Methodfor Investigating VibrationallyExcited Transients
Authors: Okamoto Hiromi , Nakabayashi Takakazu , Tasumi Mitsuo
Published: September 2007

A method for estimating vibrational quantum numbers of vibrationally excited
transients in solution is proposed. In this method, we calculate anti‐Stokes Raman
excitation profiles (REPs) which are characteristic of the initial vibrational states
involved in the Raman process, and compare them with observed anti‐Stokes intensities.
We have applied this method to vibrationally hot molecules of canthaxanthin in the So
state and those of trans‐stilbene in the S1 state. For canthaxanthin, it has been found that
the vibrationally excited transients are for the most part on the ν=1 level of the C═C
stretching mode, and that excess vibrational energy is statistically distributed among all
intramolecular vibrational modes. As for S1 stilbene, vibrational transients are shown to
be mostly on the ν=1 level for two vibrational modes examined, while the excess
vibrational energy is probably localised on the olefinic C═C stretching mode.
Coherent Motion of LowFrequency Vibrations in UltrafastExcited State Proton Transfer
Authors: Pfeiffer M. , Chudoba C. , Lau A. , Lenz K. , Elsaesser T.
Published: September 2007

Photoexcitation of internal proton transfer in the tinuvin molecule causes the excitation
of some low frequency vibrational modes which oscillate with high amplitudes in a
coherent manner over 700 fs. Such effect is observed for the first time applying two color
pump/probe measurement with 25 fs pulses. Based on resonance Raman spectra a
normal coordinate analysis of the modes is performed. It is shown that the nuclear
movement given by the normal vibration of one of the modes serves to open up a
barrierfree proton transfer path.
The Phosphorescence Spectraof Triphenylene and Truxene:A Combined Experimentaland Theoretical Investigationof the Vibronic Structure
Authors: Baunsgaard D. , El Balsami M. , Frederiksen J. , Harrit N. , Negri F. , Orlandi G. , Wilbrandt R.
Published: September 2007

The phosphorescence spectra of triphenylene and truxene, recorded in glassy solvents at
77 K, are presented. Their vibronic structure is interpreted on the basis of intensities
computed with the help of quantum‐chemical calculations. The agreement between
observed and simulated intensities is very satisfactory and contributes to improve and
complete the assignment of ground state frequencies of the two disk‐like molecules.
Temperature Induced ProteinUnfolding and Folding of RNasea Studied by Time‐ResolvedInfrared Spectroscopy
Authors: Georg H. , Wharton C. W. , Siebert F.
Published: September 2007

When a protein finds its native three‐dimensional structure from the unstructured
amino‐acid chain various processes spanning a large time range are relevant. To
understand the mechanism of protein folding one needs to cover the entire folding/
refolding (U↔N) reaction on a structural level. In the case of RNase A, the main
structural changes occur in the ms time range, that can be monitored with rapid‐scan‐
FTIR spectroscopy combined with rapid mixing techniques. To induce unfolding we
inject aqueous protein solution into a hot IR cuvette and record the time course of the
spectral changes. A lag phase is found when the unfolding conditions are relatively weak,
suggesting an unfolding intermediate.
Photoinduced IntramolecularHydrogen Transfer Reaction ofOrtho Nitrobenzyl Compounds
Authors: Takahashi Hiroaki , Watanabe Yoshiki , Sakai Makoto , Tachikawa Masanori
Published: September 2007

Time‐resolved resonance Raman and absorption spectra have revealed that the
photoinduced intramolecular hydrogen transfer reaction of ortho nitrobenzyl compounds
is initiated by the abstraction of methylene hydrogen by the ortho nitro group to
generate the ortho aci‐nitro acid isomer. In polar solvents the ortho aci‐nitro acid is
dissociated into the aci‐nitro anion and a proton, and the proton is captured by other
hydrogen accepting sites, such as 2‐pyridyl, 4‐pyridyl and 4‐nitro groups to generate the
ortho N—H quinoid, para N—H quinoid and para aci‐nitro acid isomers, respectively.
For 2‐nitroethylbenzene and 2‐ and 4‐(2′‐nitrobenzyl)pyridines the structure of the
aci‐nitro anion is very similar to that of their respective ortho aci‐nitro acid, while for
2,4‐dinitroethylbenzene the structure of the aci‐nitro anion quite resembles that of the
para aci‐nitro acid.
Reactive Intermediates in theRoom Temperature RhodopsinPhoto‐Reactions: PicosecondTime‐Resolved Cars
Authors: Atkinson George H. , Jäger Frank , Ujj Laszlo
Published: September 2007

The vibrational spectra of the batho and lumi intermediates in the room‐temperature
rhodopsin photo‐reaction are measured by picosecond time‐resolved coherent anti‐Stokes Raman spectroscopy (PTR/CARS). The instrumental principles underlying PTR/
CARS together with the advantages of PTR/CARS applications in protein reactions are
discussed.
Time‐Resolved, Step‐Scan FtirStudies Of Excited States Of d6Metal Polypyridine Complexes
Authors: Schoonover Jon R.
Published: September 2007

Time‐resolved infrared spectroscopy using step‐scan FTIR has been developed as an
approach to study transient inorganic species with lifetimes ranging from ca. 200
nanseconds to several microseconds. This approach has been applied to a variety of
problems arising following laser excitation of d6 polypyridine complexes in solution, and
several examples are shown to demonstrate the utility of this experiment.
Direct Observation of S2–S1Internal Conversion in Pyreneby Femtosecond TransientAbsorption
Authors: Neuwahl Frederik V. R. , Foggi Paolo
Published: September 2007

UV pulses of 100 fs at 340 nm are utilised to excite pyrene to the vibrationally cold S2
state. Population and depopulation processes occurring in the S2 state are investigated
by transient absorption spectroscopy with a white continuum probe. In the first 400 fs
after excitation it is possible to measure the growth and disappearance of a band at
585 nm which is assigned to the S14←S2 transition. As a consequence of the internal
conversion process from S2 to S1 state, the disappearance of the 585 nm band and the
growth of the transient spectrum due to Sn←S1 transitions can be observed. Kinetic
measurements of the S2 decay and S1 growing signals provide an estimate of the rate of
internal conversion which occurs with a time constant of 150±50 fs.
Construction of 40 NanosecondTime Resolusion Step‐Scan FtirDifference Spectrometer
Authors: Hu Xuehua , Spiro Thomas G.
Published: September 2007

A step‐scan time‐resolved Fourier transform infrared (FTIR) spectrometer was
constructed. Using 1064 nm radiation from a 9ns pulsed Nd:YAG laser as the IR
source, we have obtained both the time‐resolved spectra in the frequency domain and the
change of the transient signals in the time domain. The latter allows us to measure the
time resolution of the instrument to be about 40 nanoseconds.
Time‐Resolved Quadrupole Mass Spectrometric Studies on Pulsed Laser Ablation of TiO2
Authors: Tang Yongxin , Han Zhenhui , Qin Qizong
Published: September 2007

Pulsed laser ablation of TiO2 at 355 nm and 532 nm has been investigated using an angleand
time‐resolved quadrupole mass spectrometric technique. The major ablated species include O (m/e = 16), O2 (m/e = 32), Ti (m/e = 48), TiO (m/e = 64) and TiO2 (m/e = 80). The time‐of‐flight (TOF) spectra of ablated species are measured for the ionic and neutral ablated species, and they can be fitted by a Maxwell – Boltzmann (M – B) distribution with a center‐of‐mass velocity. The measured angular distributions of the ionic species (O+ and Ti+) and the neutral species (O and Ti) can be fitted with cos⁡nθ and a cos⁡θ  +  (1 − a)cos⁡nθ, respectively. In addition, a continuous wave oxygen molecular beam is
introduced into the ablated plume, and the enhancement of the signal intensities of TiO
is observed. It implies that the ablated Ti atoms/ions species can react with ambient
oxygen molecules in the gas phase. In the meanwhile, the physicochemical mechanism of
pulsed laser ablation of TiO2 is discussed.
Vibrational Mode Couplingto Reverse Electron Transferin (CN)5FeCNRu(NH3)5− in Solution
Authors: Wang Chengfei , Akhremitchev Boris , Walker Gilbert C.
Published: September 2007

We present charge transfer absorption, resonance Raman and time‐resolved infrared
spectral data for (CN)5FeCNRu in various solvents. The transient infrared
spectra and anisotropies reveal both non‐equilibrium vibrational populations of high
frequency modes and local solvent heating.
Femtosecond Material ResponseProbed by Phase‐Stabilized OpticalHeterodyne Detected ImpulsiveStimulated Raman Scattering
Authors: Tahara Tahei , Matsuo Shigeki
Published: September 2007

Femtosecond material response of several liquid samples were measured with use of a
newly developed “phase‐stabilized” optical heterodyne detected impulsive stimulated
Raman scattering (ISRS) spectrometer. In this apparatus, the ISRS signal generated
with ordinary transient grating geometry is mixed with femtosecond optical pulses (local
oscillator, LO) in an interferometer, and the interfered intensity is detected. The
subwavelength‐accuracy adjustment/stabilization is achieved for the optical path length
in the interferometer so that the relative optical phase between the ISRS signal and LO
can be controlled. The ISRS signals linearized to each tensor element of the third‐order
response function were obtained, and discussed.
Multiphoton Ionization and Fragmentation of CS2 Under Intense Short Pulse Laser Radiation
Authors: Koudoumas E. , De Nalda R. , Fotakis C. , Couris S.
Published: September 2007

The interaction of CS2 with intense short pulse laser radiation is studied, experimentally
using time‐of‐flight mass spectroscopy. Laser pulses of 0.5 and 5 psec at 248 and 496 nm
have been used in order to investigate the effect of the wavelength and the pulse duration
on the molecular ionization and fragmentation. As shown, for low enough intensities
the parent molecular ion is present as the most important peak in all cases. Increasing
the intensity results in extensive fragmentation, where the molecular parent ion remains
always the more intense mass peak at 496 nm while at 248 nm S+ dominates the mass
spectra. Finally, the production of multiply charged fragments is more efficient at the
longer wavelength used.
Time‐Resolved InfraredSpectroscopy of BinuclearRhenium (I) PolypyridylComplexes in Solution
Authors: Abbott L. C. , Arnold C. J. , Gordon K. C. , Hester R. E. , Moore J. N. , Perutz R. N. , Ye T.-Q.
Published: September 2007

A series of four binuclear rhenium (I) complexes of the general form [Re(CO)3Cl]2BL,
where BL is a polypyridyl bridging ligand, have been studied using ultrafast time‐resolved
UV/visible (TRVIS) and infrared (TRIR) spectroscopies. Visible excitation
produces a metal‐to‐ligand charge‐transfer (MLCT) excited state. Kinetic measurements
show that the lifetime of this MLCT state varies between 100 and 1900 ps, depending on
the structure of the bridging ligand. TRIR difference spectra show that each complex
forms a similar MLCT state which has mixed valence character.
Analytical Studies of Polychromes by Time‐Integrated Laser‐InducedBreakdown Spectroscopy
Authors: Martin Margarita , Castillejo Marta , Torres Ricardo , Silva Diego
Published: September 2007

Time integrated Laser Induced Breakdown Spectroscopy was applied to the study of real
samples of polychromes. Two samples respectively from the Spanish Baroque and from
the XV century were analysed. The time integrated spectra showed negligible contribution
of continuum background emission. The spectra of the Baroque sample indicated the
presence of vermilion; this was confirmed by Near Infrared Fourier Transform Spectroscopy.
LIBS spectra of the XV century sample showed Ca, Al, Mg, Na and Pb lines and
the molecular emissions CN(B‐X) and C2(d‐a). Relative spectral intensities were measured
as a function of the number of laser pulses delivered on the same position of the sample.
The LIBS analysis was compared to an exhaustive analytical study.
Determination of the LowestExcited State of Metal Complexesof Dipyrido[3, 2‐a:2′,3′‐c]Phenazine
Authors: Waterland Mark R. , Gordon Keith C.
Published: September 2007

The nature of the lowest excited state of rhenium and copper complexes of dipyrido[3,2‐
a:2′ ,3′‐c]phenazine (Dppz) has been determined using Resonance Raman, Time‐
Resolved Resonance Raman Spectroscopy and Spectroelectrochemistry. Comparison
of spectroelectrochemical data and excited state data show that for the complexes
studied no reduced ligand bands are observed in the excited state spectra thus the lowest
excited states are all Ligand Centred in nature. The use of substituents at the 11 and/or
12 position of the ligand has no effect on the excited state ordering.
Ultrafast Infrared and VisibleSpectroscopy of IntermolecularElectron Transfer From DimethylAniline to Coumarin 337
Authors: Akhremitchev Boris , Wang Chengfei , Walker Gilbert C.
Published: September 2007

Ultrafast visible and infrared polarization spectroscopy has been used to reveal the
orientation of donor and acceptor molecules in the intermolecular electron transfer
between coumarin 337 and dimethylaniline.
Temperature Effects Of ExcitationLaser Pulses During Step‐ScanFT‐IR Measurements
Authors: Rödig C. , Georg H. , Siebert F. , Rousso I. , Sheves M.
Published: September 2007

Replacing the chromophore of bacteriorhodopsin with chemically modified retinal
analogs which cannot isomerize, allows to measure directly side effects from the laser
pulse used for sample excitation in step‐scan FT‐IR measurements. Comparison with
static temperature difference spectra and temperature‐jump experiments shows that the
observed effects can mainly be attributed to heating of the sample by the laser pulse. The
size of resulting spectral changes is compared to difference bands of the photoreaction.
Transient Absorption and RamanStudies on Exciplex FormationDynamics of PhotoexcitedCu(II)(TMpy‐P4) With SyntheticPolynucleotide
Authors: Jeoung Sae Chae , Eom Hyo Soon , Kim Dongho
Published: September 2007

Exciplex formation dynamics of photoexcited copper(II) tetrakis (4‐N‐methylpyridyl)
porphyrin (Cu(II)(TMpy‐P4)) with added poly(dA‐dT)2 and poly(dG‐dC)2 has been
investigated by using femtosecond transient absorption and nanosecond and picosecond
transient Raman spectroscopic methods. It was observed that the decay time constant of
the exciplex is strongly dependent on the polynucleotide and has a strong correlation
with the appearance of new transient Raman bands.
Time‐Resolved Step‐Scan FtirInvestigations on the M1→M2Transition in the Light‐DrivenProton Pump Bacteriorhodopsin
Authors: Weidlich Olaf , Rödig Christoph , Siebert Friedrich
Published: September 2007

Using time‐resolved step‐scan FTIR spectroscopy, it has become possible to identify two
different M states in the 5 to 300 μs time range, which clearly differ from the MN state.
The identification has become possible by measuring a pure BR→KL difference
spectrum at 100 ns, which can be used to correct for the contributions of this
intermediate in the later difference spectra. The subtraction of the later corrected
difference spectra thus represent L→M1, M2 difference spectra with varying relative
amount of the two M states. The comparison of these spectra clearly reveals differences
in the amide‐II spectral range, and possibly also in the amide‐I range. From these
observations it can be concluded that the two M states do not differ in the chromophore
structure but in the protein structure.
The Carbonate, Co3−·, in Solution Studied by Resonance Raman Spectroscopy
Authors: Tavender Susan M. , Johnson Steven A. , Balsom Daniel , Parker Anthony W. , Bisby Roger H.
Published: September 2007

The carbonate radical () is of biological significance acting as an intermediate in
free radical‐mediated damage and is capable of oxidising amino acids and proteins. In
order to distinguish between the four possible structures of , nanosecond timeresolved
resonance Raman (TR3) experiments were undertaken. Photolysis of
persulphate at 250 nm generated the radical which then oxidised sodium carbonate.
Resonance Raman spectra of the resulting radical were obtained using a probe
wavelength of 620 nm. Point group theory calculations and interpretation of the TR3
spectra suggest that the radical has C2v
molecular symmetry.
Picosecond Raman ExcitationProfile and Transient AbsorptionSpectrum of S1 Quaterphenylin Solution
Authors: Toner W. T. , Matousek P. , Parker A. W. , Towrie M.
Published: September 2007

Intensity changes in Stokes resonance Raman spectra of photoexcited quaterphenyl are
found to result from 17 ps timescale changes in resonance frequency and width and also
in Franck‐Condon displacements. The 766 cm-1 anti‐Stokes band shows a significant
hot population which decays on a similar timescale. The results show that population
relaxation, vibronic coupling and solvent reorganisation are all significant on this
timescale.
The Resonance Raman SpectraOf Biologically Relevant PolyeneDerivatives in T1: A TheoreticalInvestigation
Authors: Negri Fabrizia , Orlandi Giorgio
Published: September 2007

The vibrational structure of the T1 resonance Raman spectra of β‐ionylidene
acetaldehyde (C15 aldehyde) and retinal are analyzed with the help of semiempirical
quantum chemical calculations. The T1 equilibrium structures and vibrational force
fields, along with the structure in the Tn state which is in resonance with the exciting
wavelength, are obtained and employed to model the spectra under the assumption of a
dominant Franck–Condon mechanism.
Vibrational Relaxation Processof Polyatomic MoleculesAdsorbed in Zeolites
Authors: Onda Ken , Yaginuma Michio , Wada Akihide , Domen Kazunari , Hirose Chiaki
Published: September 2007

The vibrational relaxation lifetimes of the CO stretching mode of Cr(CO)6 and Mo(CO)6
adsorbed in the cage of the HY, DY and NaY‐type zeolites were measured at various
temperature by pump‐probe method using picosecond infrared laser pulses. It was
shown by comparing the lifetimes that the accepting modes include both the vibrational
modes of the metal carbonyl and those associated with the cations on the zeolite surface.
The analysis of the temperature dependence of the lifetimes revealed that the number of
the excited accepting modes are four with their energy lying around 500 cm-1.
Femtosecond Mid‐InfraredSpectroscopy ofHydrogen‐Bonded Liquids
Authors: Woutersen S. , Emmerichs U. , Bakker H. J.
Published: September 2007

We perform femtosecond mid‐infrared pump‐probe spectroscopy on hydrogen‐bonded
ethanol dissolved in CCl4. We find that upon excitation of the OH‐stretching vibration
the hydrogen bonds are predissociated on a femtosecond time scale, and that the
predissociation time constant depends strongly on the hydrogen‐bond strength.
Time‐Resolved Resonance RamanStudies of Radicals From4‐Aminoresorcinol as Modelsfor the Active Site RadicalIntermediate in CopperAmine Oxidases
Authors: Bisby Roger H. , Johnson Steven A. , Parker Anthony W. , Tavender Susan M.
Published: September 2007

Radicals formed by one‐electron oxidation of 4‐aminoresorcinol have been studied as
models for the active site free radical intermediate which forms as a stable product
during anaerobic incubation of amine oxidases with amine substrates. Pulse radiolysis
shows that the radical undergoes ionisations with pKa′s of 3.4 and 6.4. Although the two
deprotonated forms are difficult to distinguish by absorption spectroscopy, they have
clearly different resonance Raman spectra. Comparison with the resonance Raman
spectrum of the enzyme intermediate shows it to be the singly deprotonated form of the
radical.
Two Distinct SolvatedStructures of Para‐Nitroanilinein Acetonitrile and TheirDissociation and ReassociationDynamics
Authors: Mohanalingam K. , Yamaguchi S. , Hamaguchi H.
Published: September 2007

We have measured the femtosecond time‐resolved absorption spectra of para‐nitroaniline
in acetonitrile just after the photoexcitation to the lowest excited singlet state. The
Singular Value Decomposition (SVD) analysis shows that two temporal evolutions
follow the photoexcitation. The fast component (0.7 ps time constant) describes the
dissociation of the 1:2 associated form to generate the 1:0 form followed by its
reassociation with AN molecules. A slower temporal evolution of 10 ps is most likely to
represent the cooling down process of the whole system.