bluuebunny/crossref_metadata_2025 huggingface dataset:
Using a Black Body Source to Enhance Line Emission in a Laser Produced Plasma
Authors: Tambay Rekha , Thareja Raj K
Published: September 2007

We report on the studies of coupling of black body radiation with metal vapors in a crossed heatpipe.
The electron density of the laser produced plasma was estimated using a Mach‐Zehnder Interferometer.
The formation of clusters in a over heated heatpipe is also reported.
A Nd:Yag Pumped Binary Laser Dye Mixture for the 397‐427 Nm Wavelength Region
Authors: French J. L. , Karolczak J. , Clouthier Dennis J.
Published: September 2007

A useful mixture of the laser dyes DPS and bis‐MSB in a 9:1 dioxane and methanol solution is described.
The binary dye system exhibits broad tunability, symmetric degradation and reasonable conversion efficiency
with 355 nm Nd:YAG pumping.
Nascent Vibrational State Distributions of ZnH(X 2∑+) and ZnD(X 2∑+) Produced in the Reactions of Zn(41P1) With H2 and D2
Authors: Umemoto Hironobu , Tsunashima Masamichi , Tsunashima Shigeru , Ikeda Hiroyuki
Published: September 2007

The reactions of Zn(41P1) with H2 and D2 were studied by employing a laser pump‐and‐probe technique. The nascent vibrational state distributions of ZnH(X 2∑+) and ZnD(X 2∑+) were determined. The distributions were much cooler than the statistically expected ones. These results are consistent with the insertive attack model proposed for other excited metal‐H2 systems. The quantum yield for the production of ZnH(X 2∑+) was measured to be low; around 0.5 of that for cn4. Three‐body dissociation processes to produce Zn(41S0) + H + H must be more dominant than the production of ZnH.
Photoelectron Spectroscopy of Mass‐Selected Copper‐Water Cluster Negative Ions
Authors: Misaizu Fuminori , Tsukamato Keizo , Sanekata Masaomi , Fuke Kiyokazu
Published: September 2007

Negative‐ion photoelectron spectroscopy has been applied in order to obtain size dependent information
about the electronic structure of clusters of metal atoms solvated with polar molecules. In the present
paper we have investigated the photoelectron spectra of Cu2-, cluster ions with 2 = 0–4 and also
those of Cu2-, with n = 0 and 1. In the spectra of Cu2-, the lowest energy bands were assigned
to the electron detachment from the CuOH-, which were produced in the source together with
the above cluster ions. The observed bands for Cu2- were all assigned to the transitions to the
states originating in the ground 2S and first excited 2D states of the Cu atom. The stepwise hydration for Cu- and Cu2- was discussed from the observed spectral shifts.
Laser Spectroscopy of Neutral Atoms in Superfluid Helium: New Environment For Spectroscopy and Chemistry
Authors: Hui Qin , Persson John L. , Beijersbergen Jaap H. M. , Takami Michio
Published: September 2007

The optical spectra of neutral atoms are studied in superfluid helium (HeII). Neutral atoms are dispersed
into HeII by laser ablation of solid samples immersed in HeII. Absorption and emission spectra of dispersed atoms are studied with pulsed dye lasers. Ytterbium is found to be a typical bubble atom which resides in a bubble‐like cavity formed by a strong repulsive force against the surrounding He atoms. Resonance quenching of LIF by accidental overlap of the resonant induced emission and broad absorption lines is observed.
Emission and Relaxation of Electronically Excited O2 Doped in a Low Temperature N2 Crystal
Authors: Kajihara Hideo , Okamura Tomoyuki , Okada Fumio , Koda Seiichiro
Published: September 2007

Oxygen molecules doped in a low temperature N2 crystal were irradiated at 240‐260 nm. Two emission band systems were observed, one from the v′ = 0 level of A′ 3Δu
state to X3Σg-.
state and the other, from the v′ = 0 level of c1Σu-.
state to at a1Δg state, independent on the excitation wave length. The latter emission grew together with the decay of the former emission at around the same rate after the pulsed laser excitation, which implies that the vibrational levels of c state lying below the v′ = 0 level of Ω
= 3 of A′ state are populated from the v′ = level of A′ state, though some additional mechanism for populating the c state may exist. The rate was found to become larger with the increase of the crystal temperature. It was also found that the excitation spectrum obtained by monitoring the A′–X emission was the same as that obtained by the c–a emission. The progress of vibrational relaxation, coupling with the intersystem crossing between the Herzberg states, will be discussed.
Photothermal Ablation of Polystyrene Film by 248 NM Excimer Laser Irradiation:a Mechanistic Study by Time‐Resolved Measurements
Authors: Tsuboi Yasuyuki , Sakashita Shin-Ichi , Hatanaka Koji , Fukumura Hiroshi , Masuhara Hiroshi
Published: September 2007

Laser ablation mechanism at 248 nm irradiation of polystyrene film was investigated and discussed. An
ablation threshold was determined by etch depth measurement and nanosecond photographic observation.
Temperature at the threshold was evaluated to be 370℃ by using an effective absorption coefficient
which was confirmed by transmission measurement of the excitation pulse. The temperature was in good
agreement with that of thermal degradation of the polymer, showing that 248 nm ablation of polystyrene
was brought about by a photothermal process. Nanosecond photography upon the ablation could be
well interpreted from the photothermal viewpoint. Moreover, dynamics of excited species revealed by
nanosecond time‐resolved luminescence measurements was inferred in relation to the ablation.
Research Activity Using Molecular Beam and Laser Techniques: A Progress Report
Authors: Castaño J. , Skowronek S. , Garay M. , Bescós B. , Zapata V. , Orea J. M. , Laplaza A. , Tardajos G. , Pereira R. , Rinaldi C. , Ureña A. González
Published: September 2007

We shall briefly describe the main research areas, now in progress in our molecular
beam and laser group. The current activity includes our traditional molecular beam
work as well as other experiments carried out in the new labs of our Institute. Essentially
we present here the current progress on Crossed‐beam and Beam‐gas Chemilumine
scence, Laser‐induced Beam Surface Reaction, Laser Analytical Chemistry, Laser‐initiated
Reactions Studies by Chemiluminescence and Laser‐induced Fluorescence, Spectroscopy
and Structure of van der Waals molecules. For each section recent results are
presented. Due to the basic scope of the present progress report the emphasis is made
on the new experimental developments as well as on the capabilities of both basic and
applied research techniques now operative in our group.
Ion‐Size Effects in the Growth Sequences of Metal‐Ion‐Doped NobleGas Clusters
Authors: Lüder Christian , Prekas Dimitris , Velegrakis Michalis
Published: September 2007

We have studied the stability and the structure of doped noble gas cluster ions of the type
M+Xn, (M=In, Al, Na, X=Ar, Kr, Xe) by systematically changing the composition
M/X and observing changes in the magic number patterns appearing in the mass spectra.
When the metal ion radius is comparable to the radius of the noble gas atom, the mass
spectra show the familar icosahedral magic numbers n+ 1=13,19,23,26,29,32,
46, 55,… In constrast, for metal ions with radii significantly smaller than the noble
gas atoms, we observe a new series of magic numbers n + 9, 11, 17, 21,24, 26,… This
series converts into the icosahedral one for larger clusters. Using a simple hard sphere
packing model, we show that this new series of magic numbers is consistent with a cluster
growth sequence which is based on a capped square antiprism (CSA) geometrical
structure of the clusters.
The Collisional Behaviour of Ba[6s5d(3DJ)] with CH3ClInvestigated by Time‐Resolved Atomic Emission and MolecularChemiluminescence BaCl (A2∏1/2,3/2,B2∑+ → X2∑+) Following the Pulsed Dye‐Laser Excitationof Atomic Barium
Authors: Husain D. , Lei Jie , Castano F. , Rayo M. N. Sanchez
Published: September 2007

The collisional behaviour of Ba[6s5d(3DJ)], 1.151 eV above the 6s 2( 1S0) ground state,
is investigated in the presence of CH3Cl at elevated temperature (900 K) following
the initial pulsed dye‐laser excitation of atomic barium via the allowed transition at
λ = 553.5nm{Ba[s66p(1P1)] ← Ba[6s2(1S0)]} in excess helium buffer gas. The optically
mestastable Ba(3DJ) is then subsequently generated in the ‘long‐time domain’ by a
combination of radiative and collisional processes and may then be monitored b, the
spectroscopic marker atomic emission transition at ,λ = 791.1nm{Ba[6s6p(3P1)] → Ba[6s2(1S0)]}
described previously. Following the collision of {Ba[6s6d(3D1)]} with
CH3Cl, the following molecular chemiluminescence transitions of BaCl are also monitored
as a function of time: BaCl(A2∏1/2 → X2∑+, λ = 966nm, △v = 0)
, BaCl(A2∏3/2 → X2∑+, λ = 910nm, △v = 0)and BaCl(B2∑+ → X2∑+, λ = 843nm, △v = 0), the
atomic and molecular profiles all demonstrating exponential decays characterised by
decay coefficients which are equal in given reactant mixtures. It may thus be readily seen
from the kinetic analysis that the three molecule states, BaCl(A2∏1/2,3/2, B2∑+), are
generated directly on collision of Ba(3DJ) with CH3Cl via exothermic reactions. A
detailed kinetic analysis employing both the integrated intensities of the atomic emission
and these long wavelength molecular emissions, coupled with optical sensitivity calibrations, yields branching ratios in the BaCl(A2∏1/2,3/2, B2∑+) states. These are
found to be as follows: BaCl(A2∏1/2)4, 68%, BaCl(A2∏3/2)1.29%, BaCl(B2∑+)0.24%
The logarithmic variation of these branching ratios with the energies of the states is
essentially Boltzmann in character, with an effective temperature close to the ambient
temperature of the measurements. This is consistent with the absence of propensity in the
yields of these excited molecular states on collision, reflecting the role of late barriers in
the potential surfaces involved.
Near‐Resonant Nonlinear OpticalProperties of Pseudoisocyanine J‐Aggregates in Langmuir‐BlodgettLayers
Authors: Feller K.-H. , Gadonas R. , Pugzlys A. , Möbius D.
Published: September 2007

The nonlinear optical properties of pseudoisocyanine J‐aggregates in Langmuir‐Blodgett
films have been investigated by means of degenerate four wave mixing (DFWM) process.
The conversion efficiency of the DFWM signal and the estimated third order
susceptibility were found to be comparable with those of pseudoisocyanine J‐aggregates
in solution under comparable resonance conditions. The intensity dependence of the
converted (DFWM) signal is interpreted as resulting from different processes including
saturation, exciton‐exciton annihilation and secondary processes of dynamical disorder.
Polymeric Matrices for Lasing Dyes: Recent Developments
Authors: Costela A. , Garcia-Moreno I. , Figuera J. M. , Amat-Guerri F. , Sastre R.
Published: September 2007

An overview of recent results obtained by our group on the development of polymeric
solid‐state media incorporating either Rhodamine or Coumarin dyes is presented. The
effect on the laser performance of the rigidity and viscoelastic properties of the polymeric
matrix has been investigated. Lasing efficiencies similar to those found in ethanolic
solution, and improved photochemical stability, as compared with that obtained in
previous polymeric materials, were demonstrated for solid solutions of Rhodamine 6G
(Rh6G) in appropriate copolymer formulations of 2‐hydroxyethyl methacrylate
(HEMA) and methyl methacrylate (MMA). Further improvements in photostability
were obtained when modified Rh6G molecules were copolymerized with HEMA and
MMA. When samples of this new highly homogeneous gain medium were placed in a
rotating system, where the laser medium was scanned in a continuous way, a stable laser
output with no sign of degradation after 500,000 shots was accomplished for transversal
pumping at 337 nm with 1.7 mJ pulses from a N2‐laser at 2 Hz repetition rate.

The effect on laser operation of different polymerization methods, dye concentration,
and composition of the polymeric matrix was also investigated for Coumarin‐doped gain
media. Conditions were found that significantly improved both lasing efficiency and
photostability in Coumarin 540A (C540A)‐doped polymeric matrices. Insight into the
main photodegradation mechanisms of this dye was provided by the study of
fluorescence and lasing properties of a number of C540A solutions with increased
viscosity, from liquid solution to solid polymer matrix.
Transient Raman Spectroscopyof Isotope‐Substituted Speciesof Bacteriochlorophyll a,Bacteriopheophytin a AndChlorophyll a: Changes in theBond Orders in the MacrocyclesUpon Triplet and SingletExcitation
Authors: Koyama Yasushi , Limantara Leenawaty , Sashima Tokutake
Published: September 2007

The S0, T1 and S1 Raman spectra of bacteriochlorophyll a, bacteriopheophytin a and
chlorophyll a were recorded for the species of natural abundance isotopic composition
and those of totally substituted with 15N, 13C and 2H isotopes. Based on empirical
assignments of the Raman lines, changes in the bond orders in the macrocycle upon
triplet and singlet excitation are discussed.
Electronic and VibrationalCoherence in PhotosyntheticCofactors: Comparisonof Solutions and Proteins
Authors: Arnett D. C. , Book L. D. , Moser C. C. , Dutton P. L. , Scherer N. F.
Published: September 2007

The interaction between photosynthetic cofactors and the surrounding bath or protein
environment is addressed via experimental measurements of the optical coherence
responses from bacteriochlorophylla (Bchla) chromophores within the photosynthetic
reaction center (RC) of Rhodobacter sphaeroides and solutions of Bchla monomers in
THF and pyridine. The results indicate that both the spectrum of fluctuations and
chromophore bath coupling strengths vary between solutions and protein. In particular,
the protein environment yields faster dephasing, faster spectral diffusion, and
significantly more inhomogeneity than solutions.
Complete Determination ofRelaxation Parameters FromTwo‐Dimensional RamanSpectroscopy
Authors: Chernyak Vladimir , Piryatinski Andrei , Mukamel Shaul
Published: September 2007

Using the model of a weakly‐anharmonic, underdamped oscillator coupled to a bath, we
demonstrate that the 2D time‐resolved Raman signal carries information about the
population decay T1, the homogeneous dephasing T2, and the inhomogeneous dephasing
T1 relaxation timescales. We distinguish between two projections of the 2D signal: first,
the echo signal, which is stretched in the diagonal direction decays with T2, and the
second which is stretched along one axis is related to the population relaxation and
decays with T1. The width of both signals reflects T1. Equations of motion for vibrational
coherence and population variables are employed in these calculations.
Excited States and Intermediatesby Time‐Resolved InfraredSpectroscopy
Authors: Turner J. J. , George M. W. , Clark I. P. , Virrels I. G.
Published: September 2007

For coordination compounds containing CO or CN groups, fast time‐resolved infrared
spectroscopy (TRIR) provides a convenient method of probing excited states and
intermediates. TRIR has proved particularly powerful for probing the structure and
kinetics of organometallic intermediates. The interpretation is particularly straightforward
when combined with IR data from matrix isolation experiments, although there
can be some subtle differences. In excited state studies, shifts in ν(CO) and ν(CN)
frequencies, from ground to excited state, are sensitive to the changes in electron
distribution on excitation, thus allowing the distinction between charge‐transfer and
non‐charge‐transfer transitions. Subtle effects on excited state ν(CO) band positions
occur with change from fluid to rigid solvent‐“infrared rigidochromism”. There is often
a change in ν(CO) band width on excitation; this can be interpreted in terms of specific
interactions between the excited species and the solvent. This paper presents some of our
recent work in this area.
Solute‐Solvent Energy TransferAnd Cooling Kineticsof Photoexcited S1Trans‐StilbeneProbed With Picosecond RamanSpectroscopy: ComparisonBetween Chloroform andChloroform‐d Solutions
Authors: Iwata Koichi , Hamaguchi Hiro-o
Published: September 2007

Cooling kinetics of trans‐stilbene (tSB) photoexcited to a vibrationally excited state in
the first excited singlet (S1) manifold was studied with picosecond time‐resolved Raman
spectroscopy. The observed cooling curves of S1tSB in chloroform (CHCI3) and in
chloroform‐d (CDCl3) were identical within the experimental uncertainties. For S1tSB
in chloroform, there was no experimental evidence for strong intermolecular vibration‐vibration
(V–V) resonance energy transfer in the picosecond to sub‐picosecond time
region.
Time‐Frequency ResolvedCoherent Raman ScatteringFrom Molecular Liquidsand Their Mixtures With Quasi‐CwNoisy Light: I(2) CRS Spectrograms
Authors: Ulness Darin J. , Stimson Michael J. , Kirkwood Jason C. , Albrecht A. C.
Published: September 2007

It is demonstrated how time‐frequency resolved coherent Raman scattering (CRS)
signals generated by broadband, non‐transform limited, quasi‐cw (noisy) light can be
sensitive probes of molecular vibrational dynamics. The coherent Raman scattering
signals from molecular liquids and their mixtures with noisy light are dispersed onto a
CCD array and probed interferometrically to produce time‐frequency domain spectrograms. These spectrograms offer an extensive oversampling of the data resulting in
improved precision of measured parameters over previous noisy light methods. This
technique has been very useful in measuring small changes in material parameters, such
as Raman frequency shifts and linewidth changes, in dilution series with Raman inactive
diluents. Very recently theory and experiment have extended to include mixtures with
multiple Raman resonances. Several examples of experiments are presented and
discussed.
Molecular Dynamics Investigatedby Temporally Two‐DimensionalCoherent Raman Spectroscopy
Authors: Lau A. , Pfeiffer M. , Kozich V. , Kummrow A.
Published: September 2007

A six‐wave set‐up is described to determine molecular dynamics in the condensed phase.
Applying two independent time delays between excitation and probe pulses additional
information on the dynamics should be obtainable. We show experimentally that such
investigations can be carried out with noisy light having intensity fluctuations in the
femtosecond region. As first result we found a fast relaxation time in neat nitrobenzene
of 100 fs, becoming even faster in mixtures with low viscosity liquids. Switching on a
Raman resonance yields a longer relaxation time, which could be explained by an
additional contribution by that vibration.
Vibrational Cooling After PhotoIsomerisation: First Applicationof a Novel IntramolecularThermometer
Authors: Hamm P. , Ohline S. , Zurek M. , Röschinger T.
Published: September 2007

Femtosecond VIS‐pump‐IR‐probe experiments (time resolution: 300fs, detectable
absorption change: 5.10-5 , frequency range: 1000–1800 cm-1) were applied to the
ultrafast photo isomerisation of azobenzene and the protonated Schiff base of retinal.
The energy of the pump photon heats the vibrational system of the molecule, leading to
pronounced anharmonic frequency shifts which are dominated by the anharmonic
coupling between the investigated high frequency modes to hot low frequency modes. A
model taking into account this intramolecular anharmonicity and assuming a well
defined intramolecular temperature gives a good fit of the experimental data.
The Radical Cation of Bithiophene:An Experimental and TheoreticalStudy
Authors: Keszthelyi T. , Grage M. M.-L. , Wilbrandt R. , Svendsen C. , Mortensen O. S.
Published: September 2007

The electronic absorption spectrum of the bithiophene radical cation prepared by
γ‐irradiation in a glassy Freon matrix is presented, together with the Raman spectra
excited at 550 and 425 nm, in resonance with the two absorption bands. The 425 nm
excited Raman spectrum was also recorded in a room temperature acetonitrile solution,
in this case the radical cation was generated via a photoinduced electron transfer
reaction. The resonance Raman spectra were interpreted with the help of density
functional theory calculations. The results indicate the existence of at least two rotamers
of the bithiophene radical cation. The time‐domain method was applied to the
simultaneous fitting of the absorption and resonance Raman spectra.
Pump Probe Anisotropy Studiesof the PhotosyntheticReaction Center
Authors: Arnett D. C. , Moser C. C. , Dutton P. L. , Scherer N. F.
Published: September 2007

The photosynthetic reaction center of Rb. sphaeroides is investigated by unique pump‐probe
anisotropy methods using 13 fs optical pulses tunable throughout the near IR
absorption band. The time and wavelength resolved pump probe anisotropy transients
yield detailed experimental descriptions of the energy levels, and of the
excitonically coupled special pair (P), and dynamics prior to charge separation,
particularly energy transfer from the accessory bacteriochlorophylla′s (B) to the special
pair (P).
A Theoretical Study of theDynamics of Vibrational WavePackets in the 1g State Of Xe2
Authors: Castillo J. F. , Reid K. L.
Published: September 2007

We present a theoretical description of the dynamics of vibrational wave packets in the
1g state of Xe2. As an illustration, a simulation of a picosecond pump excitation‐probe
ionization laser experiment is carried out. The initial wavepacket is calculated using an
explicit modelling of the short‐pulse excitation process and propagated for up to
160 picoseconds. Evidence of fractional and full revivals of the wavepacket has been
found and analyzed. The time delayed ionization signal is simulated using first order
perturbation theory and shows clear oscillations corresponding to the temporal
development of the wavepacket.
Short‐Time PhotodissociationDynamics of 1‐Chloro‐2‐IodoethaneFrom Resonance RamanSpectroscopy
Authors: Zheng Xuming , Phillips David Lee
Published: September 2007

We have obtained A‐band absorption resonance Raman spectra of 1‐chloro‐2‐
iodoethane in cyclohexane solution. We have done preliminary time‐dependent
wavepacket calculations to simulate the resonance Raman intensities and absorption
spectrum in order to learn more about the short‐time photodissociation dynamics. We
compare our preliminary results for 1‐chloro‐2‐iodoethane with previous resonance
Raman results for iodoethane and find that there appears to be more motion along non‐
C—I stretch modes for 1‐chloro‐2‐iodoethane than for iodoethane. This is
consistent with results of TOF photofragment spectroscopy experiments which indicate
much more internal excitation of the photoproducts from 1‐chloro‐2‐iodoethane
photodissociation than the photoproducts from iodoethane photodissociation.
Structure‐ReactivityCorrelations of Excited Statesof Perfluorinated Compounds:A Time Resolved Raman Study
Authors: Anandhi R. , Balakrishnan G. , Mohandas P. , Umapathy S.
Published: September 2007

This paper reports the TR3 spectral studies on perfluorinated organic systems with the
objective to understand the influence of perfluorination on the excited states. We have
recorded the TR3 spectra and Raman excitation profiles of the triplet excited states of
decafluorobenzophenone and fluoranil. It is found that the influence of perfluorination is
more pronounced in the triplet excited state than the ground state and thus leads to
enhanced reactivity for perfluorinated compounds through larger structural distortions.
Modeling the Transient Changesin the Soret‐Resonant RamanIntensities of Hemoglobin DuringThe R→ T Transition
Authors: Rush Thomas S. , Kumble Ranjit , Spiro Thomas G.
Published: September 2007

We have performed resonance Raman (RR) intensity calculations of the Soret‐resonant
Raman spectra of Ni and Zn Porphine to investigate observed core size intensity
differences in the time‐resolved Soret‐resonant Raman (RR) spectra of hemoglobin. It
was found that the metalloporphine intensities mainly derive from the expansion of the
Cα—Cm and Cβ—Cβ bonds in the excited state, and that the observed differences are
mainly due to the larger core‐sized heme having a decreased Cα—Cm force constant and
larger excited state porphyrin ring expansion.
Picosecond Raman Investigationof the Structure and Reactivityof 4,4′‐Bipyridine in the S1 State
Authors: Buntinx G. , Bussotti L. , De Waele V. , Didierjean C. , Poizat O.
Published: September 2007

The lowest excited singlet state (S1) of 4,4′‐bipyridine (44BPY) has been studied in water
and methanol by using pump‐probe time‐resolved resonance Raman spectroscopy in the
picosecond time domain. Spectroscopic evidence for a disymmetric S1 structure with
localization of the electronic excitation in one of the two pyridyl rings is given. The fast
formation of the N‐hydro radical 44BPYH• from the S1 state is clearly observed in
methanol.
Recent Development of NonlinearSpectroscopy in Liquids
Authors: Tominaga Keisuke
Published: September 2007

Recent developments of nonlinear spectroscopy in liquids are reviewed. Especially, off‐resonant
fifth and seventh order nonlinear techniques are discussed in light of their
application to the studies of microscopic dynamics. Vibrational echo experiments and
overtone vibrational dephasing spectroscopy are examples of the higher order nonlinear
spectroscopy.
Transient Resonance RamanStudies of Ru(II) Complexes in DNAand in Homogeneous Media
Authors: Coates Colin G. , McGarvey John J. , Bell Steven E. J. , Jacquet Luc , Kelly John M. , Keyes Tia , Vos Johannes G.
Published: September 2007

Transient resonance Raman (TR2) spectroscopy has been used to investigate the metalligand
charge‐transfer (MLCT) excited states of Ru(II) polypyridyl complexes inDNAand
in homogeneous solution. In DNA, complexes of the type [Ru(L)2(L′)]2+ were studied,
where L=2, 2’‐bipyridyl (bpy), 1,4, 5, 8‐tetraazaphenanthrene (tap), and L′ dipyrido
[3,2:a‐2′ ,3′:c]‐phenazine (dppz) or 1,4,5,8,9,12‐hexaazatriphenylene (HAT). For
[Ru(bpy)2(HAT)]2+, the enhancement pattern of vibrational modes in the TR2 spectra
attributable to reduced HAT⋅− in the triplet MLCT state suggest perturbations to the
intraligand transition of HAT⋅− in the presence of DNA. Transient RR spectra for
[Ru(tap)2(dppz)]2+ are indicative of formation of the species RunII(tap⋅−)(tap)(dppz) by
electron transfer from DNA to the triplet MLCT state of the complex.

TR2 spectra for complexes of the type,
, n=1, 2 where L=a triazole
bridging ligand, illustrate the use of the technique as a probe of the response of MLCT
states to the electronic environment.
Femtosecond Infrared Studiesof Chemical Bond Activation
Authors: Asplund M. C. , Yang H. , Kotz K. T. , Bromberg S. E. , Wilkens M. J. , Harris C. B.
Published: September 2007

The identification of the intermediates observed in bond activation reactions involving
organometallic complexes on time scales from femtoseconds to milliseconds has been
accomplished through the use of ultrafast infrared spectroscopy. C—H bond activation
by the molecule Tp*Rh(CO)2 showed a final activation time of 200 ns in cyclic solvents,
indicating a reaction barrier of 8.3 kcal/mol. An important intermediate is the partially
dechelated η2‐Tp*Rh(CO)(S) solvent complex, which was formed 200 ps after the initial
photoexcitation. Si—H bond activation by CpM(CO)3 (M=Mn, Re) showed some
product formation in less than 5 ps, indicating that the Si—H activation reaction is
barrierless. The activated product was formed on several timescales, from picoseconds to
nanoseconds, suggesting that there are different pathways for forming final product
which are partitioned by the initial photoexcitation.
Infrared Spectral Hole Burningof 1:1 Hydrogen‐Bonded Complexesin Solution
Authors: Arrivo S. M. , Kleiman V. D. , Grubbs W. T. , Dougherty T. P. , Heilweil E. J.
Published: September 2007

Transient picosecond infrared (IR) spectra of the OH and NH‐stretch (v=0–1) absorption
bands of several hydrogen‐bonded complexes have been investigated. Solutions of
1:1 complexes of weak acids (methanol, triethylsilanol and pyrrole, < 0.1 mol/dm3) and
bases (acetonitrile, pyridine and tetrahydrofuran, < 2 mol/dm3) in CCl4 at 295 K were
interrogated with IR excitation and broadband probing. Lorentzian‐shaped absorption
bands are uniformly bleached while those with near‐Gaussian bandshapes produce
transient spectral holes. These results indicate a base functionality and hydrogen‐bond
strength dependence for determining the broadening mechanisms of these absorptions.
Femtosecond TransientAbsorption Studies of SimplePolyenes in Solution
Authors: Ohta Kaoru , Naitoh Yukito , Tominaga Keisuke , Hirota Noboru , Yoshihara Keitaro
Published: September 2007

We have conducted femtosecond transient absorption experiments on the excited‐state
dynamics of trans‐ and cis‐hexatriene (HT) in solution. The transient absorption in the
visible region decays with the time constant of about 500 fs, indicating that the internal
conversion (IC) to the ground state occurs quite efficiently. The bleach recovery signal
contains several time constants. The vibrational relaxation in the ground state occurs in
10–20ps and the slow relaxation process, which may be due to the conformational
change around C—C single bond, proceeds in a subnanosecond time scale.
Picosecond Transient RamanSpectra of S1 Bis(Methylstyryl)‐Benzene: Observation of S1←SnResonance Emission
Authors: Gustafson Terry L. , Leonard James D.
Published: September 2007

We have been studying the excited state spectra of several molecules related to
electroluminescent conducting polymers. The excited state structure corresponds to the
conducting state in these systems. We have obtained data on 1,4‐bis(2,2′‐methylstyryl)‐
benzene (2MSB) as a model system of poly (P‐phenylenevinylene) (PPV). We observe
both sharp and broad features in the spectra. The sharp bands occur at a constant energy
shift relative to the probe wavelength. We attribute the sharp bands to resonance Raman
bands of the S1 state of 2MSB. We assign the broad band at ∼740 nm to resonance
emission between Sn and S1. We believe that this is the first observation of resonance
secondary radiation (RSR) between two electronically excited states in a large molecule.
Time‐Resolved Terahertz Spectroscopy of Condensed Phase Reactions
Authors: McElroy Richard , Wynne Klaas
Published: September 2007

Ultrafast time‐resolved visible‐pump, far‐IR (THz) probe spectroscopy has been
developed in our lab and has been applied to study carrier dynamics in photoexcited
GaAs and dipole solvation dynamics in betaine and p‐nitroaniline. This type of
spectroscopy enables us to study for the first time the nonequilibrium interaction
between excited electronic states and low frequency vibrational modes.
Vibrational Energy Relaxation inthe (d, d) Excited State Of NickelOctaethylporphyrin
Authors: Mizutani Yasuhisa , Uesugi Yuki , Kitagawa Teizo
Published: September 2007

The formation of a hot photoproduct of nickel octaethylporphyrin (NiOEP) upon ππ*
excitation and its subsequent vibrational energy relaxation were monitored by
picosecond time‐resolved resonance Raman spectroscopy. Resonance Raman bands
due to the photoproduct instantaneously appeared upon the photoexcitation. Their
intensities decayed with a time constant of 330±20ps, which indicates electronic
relaxation form the (d, d) excited state (B1g) to the ground state (B1g). Anti‐Stokes ν4
band of the hot (d, d) excited state of NiOEP appeared immediately after the excitation
and decayed with time constants of 11±2 and 330±40 ps. In contrast, the rise of anti‐
Stokes ν7 intensity was not instantaneous but delayed by 2.6±0.5 ps, which suggests that
IVR has not been completed in a subpicosecond time regime.
Enantioenrichments of α ‐Amino Acids With High‐Intensity Excimer Laser
Authors: Shimizu Yuichi
Published: September 2007

It has been found that the irradiation with highly intense circularly polarized light (CPL)
from an XeF (351 nm) laser can induce the enantiodifferentiation of racemic methionine
with reasonable enantiocontrol by switching the sense of the CPL. Also, a similar result
was obtained for threonine and it was newly revealed that the enantioenrichment is
largely affected by the chemical structure, especially the functional groups, of α‐amino
acids, to cause photodecomposition such as decarboxylation and deamination. Furthermore,
it was shown for the first time that the irradiation of a proline (Pro)‐valine
(Val) mixture with the CPL induces their enantioselective decomposition simultaneously,
suggesting the occurrence of intermolecular interaction between Pro and Val.
Triplet 1‐Nitronaphthalene andCompetitive Energy and ElectronTransfer Reactions WithTrans‐Stilbene
Authors: Fournier T. , Scholes G. D. , Gould I. R. , Tavender S. M. , Phillips D. , Parker A. W.
Published: September 2007

A time resolved resonance Raman (TR3) study of 1‐nitronaphthalene (1NN) first triplet
excited state in various solvents is combined with ab initio calculations to determine the
nature and the geometry of this state in environments of different polarity. A transient
absorption and TR3 study of the reactions of triplet 1NN with trans‐stilbene (tS) in
solution in both non‐polar and polar solvents is reported. In polar solution, 31NN acts
as an electron acceptor whereas in non‐polar solution only energy transfer to tS is
observed. Moreover, at high concentrations of tS, the radical cation tS+ reacts with
ground‐state tS to form a dimer radical cation (tS2)+. Differences between the Raman
spectra of the monomeric and the dimeric radical cations are reported in the 1500–1650 cm-1 region. The switch from energy to electron transfer when going from nonpolar
to polar solutions is discussed in terms of the Marcus‐Hush theory of electron transfer.
Step‐Scan Fourier TransformInfrared Absorption DifferenceTime‐Resolved SpectroscopyStudies of Excited State DecayKinetics and Electronic Structureof Low‐Spin d6 Transition MetalPolypyridine Complexes With 10Nanosecond Time Resolution
Authors: Smith Gregory D. , Chen Pingyun , Chao James L. , Omberg Kristin M. , Kavaliunas Darius A. , Treadway Joseph A. , Meyer Thomas J. , Palmer Richard A.
Published: September 2007

Step‐scan Fourier transform absorption difference time‐resolved spectroscopy (S2FTIR
∆A TRS) has been used to collect mid‐IR time‐resolved infrared spectra of the transient
electronic excited states of polypyridine transition metal complexes with 10 ns time
resolution. The time‐resolved data can be used for kinetic analysis or to generate
“snapshots” of the lowest lying excited state. Shifts of vibrational bands in the excited
state relative to the ground state can be used to infer significant details of the electronic
structure of the excited state. The multiplex advantage of the FTIR technique allows a
wide variety of vibrational bands to be analyzed for this purpose. In the example
illustrated, the shift of the ester ν(CO) band in {Ru(bpy)[4,4′‐(COOEt)2bpy]2}2+
compared to those in related complexes has been used to address the question of electron
delocalization in the excited state.
Synthesis, Characterization and Theoretical Investigation on the Optical Nonlinearityof WS4Co(dppe)(DMF) Heterometallic Cluster Compound
Authors: Wu Kechen , Lin Ping , Wu Xintao , Chen Ling
Published: September 2007

A novel hetero‐metallic binuclear cluster WS4Co(dppe)(DMF) has been synthesized and characterized. The crystal has a structure of monoclinic space group P21. Ab initio CPHF calculations are performed on the static first hyperpolarizabilities of the molecular building blocks of the cluster. The microscopic structural origin of nonlinear optical properties are discussed in‐depth. The charge‐transfer between tungsten ion and cobalt ion in a molecular building block critically contributes to the optical nonlinearity, while the joint effect of the ligands makes sufficient enhancements. The study is helpful to search for novel IR nonlinear optical materials among the transition metal cluster compounds.
Electromagnetic Modelling of Raman Enhancement from Nanoscale Structures as a Means to Predict the Efficacy of SERS Substrates
Authors: Brown Richard J. C. , Wang Jian , Milton Martin J. T.
Published: September 2007

The requirement to optimise the balance between signal enhancement and reproducibility in surface enhanced Raman spectroscopy (SERS) is stimulating the development of novel substrates for enhancing Raman signals. This paper describes the application of finite element electromagnetic modelling to predict the Raman enhancement produced from a variety of SERS substrates with differently sized, spaced and shaped morphologies with nanometre dimensions. For the first time, a theoretical comparison between four major generic types of SERS substrate (including metal nanoparticles, structured surfaces, and sharp tips) has been performed and the results are presented and discussed. The results of the modelling are consistent with published experimental data from similar substrates.
DNA-Metallodrugs Interactions Signaled by Electrochemical Biosensors: An Overview
Authors: Ravera Mauro , Bagni Graziana , Mascini Marco , Osella Domenico
Published: September 2007

The interaction of drugs with DNA is an important aspect in pharmacology. In recent years, many important technological advances have been made to develop new techniques to monitor biorecognition and biointeraction on solid devices. The interaction between DNA and drugs can cause chemical and conformational modifications and, thus, variation of the electrochemical properties of nucleobases. The propensity of a given compound to interact with DNA is measured as a function of the decrease of guanine oxidation signal on a DNA electrochemical biosensor. Covalent binding at N7 of guanine, electrostatic interactions, and intercalation are the events that this kind of biosensor can detect. In this context, the interaction between a panel of antitumoral Pt-, Ru-, and Ti-based metallodrugs with DNA immobilized on screen-printed electrodes has been studied. The DNA biosensors are used for semiquantitative evaluation of the analogous interaction occurring in the biological environment.
Endocrine Precursor Lesions and Microadenomas of the Duodenum and Pancreas with and without MEN1: Criteria, Molecular Concepts and Clinical Significance
Authors: Anlauf Martin , Perren Aurel , Klöppel Günter
Published: September 2007

Proliferative changes in the neuroendocrine cells that precede neoplasia are of interest for the understanding of tumorigenesis and the early recognition of neuroendocrine tumors. This review focuses on precursor lesions of duodenal and pancreatic neuroendocrine tumors in multiple endocrine neoplasia type 1 (MEN1) and also discusses 2 new disease entities of pancreatic microadenomatosis. The gastrinomas observed in MEN1 are almost exclusively localized in the duodenum and are multicentric. It has been shown that, in contrast to sporadic duodenal gastrinomas, they are associated with hyperplastic gastrin cell lesions and tiny gastrin-producing microtumors less than 500 µm in diameter. In the pancreas, microadenomatosis (multiple tumors up to 5 mm in diameter) is a feature of MEN1. These microadenomas predominantly express glucagon and pancreatic polypeptide, but do not cause a hormonal syndrome. Approximately 50% of MEN1 minigastrinomas in the duodenum and almost all microadenomas in the pancreas show allelic deletion of the MEN1 gene and therefore may represent ‘initial’ neoplasms. In contrast, endocrine cell precursor lesions retain heterozygosity. Pancreatic microadenomatosis was also found unassociated with hereditary syndromes and 2 monohormonal types were identified: (1) glucagon-producing microadenomatosis and (2) insulin-producing microadenomatosis, both associated with macrotumors. Whether these types of microadenomatosis represent novel disease entities and how to diagnose and treat these patients remains to be clarified by further studies.
GLTSCR2 Sensitizes Cells to Hypoxic Injury without Involvement of Mitochondrial Apoptotic Cascades
Authors: Yim Ji-Hye , Kim Yong-Jun , Cho Young-Eun , Ko Jeong-Hun , Kim Su-Mi , Kim Jee-Youn , Park Jae-Hoon
Published: September 2007

Objective: We attempted to identify novel genes that induce hypoxic cell death to better understand the molecular mechanisms underlying hypoxia-induced cell death. Through this process the GLTSCR2 gene was found. The purpose of this work was to investigate the role of GLTSCR2 in hypoxic cell death pathways. Methods: This work focuses on an investigation of roles and mechanisms of GLTSCR2 in hypoxic cell death by means of subtractive hybridization, RT-PCR, Western blot, immunocytochemistry, cell death assay, transient gene overexpression, and determination of mitochondrial membrane potential. Results: We found that GLTSCR2 was transcriptionally suppressed by hypoxia, and ectopic expression of GLTSCR2 sensitized cells to hypoxic injury. Interestingly, while the majority of hypoxia-inducible pro-death proteins signal through mitochondrion-dependent pathways, GLTSCR2-overexpressed cells underwent apoptosis in a mitochondrion- and caspase-independent manner. Conclusion: Our data categorizes GLTSCR2 as a proapoptotic protein sensitizing cells to hypoxic injury when overexpressed.
Hepatosplenic Gamma/DeltaT-Cell Lymphoma Masquerading as Alcoholic Hepatitis and Methadone Withdrawal
Authors: Lopez Morra H.A. , Fine S.N. , Dickstein G.
Published: September 2007

Hepatosplenic gamma/delta T-cell lymphoma is a rare neoplasm of mature gamma/delta T-cells with sinusoidal infiltration of spleen, liver, and bone marrow. Patients are predominantly adolescent and young adult males and usually present with marked hepatosplenomegaly. Pancytopenia is another common finding. Despite an initial response to treatment, patients have a median survival of one to two years. In this report, we document a case of alcoholic hepatitis and methadone withdrawal masquerading unsuspected, hepatosplenic gamma/delta T-cell lymphoma with unusual CD20 positivity.
Effect of a Selective Endothelin Receptor A Blocker on Cardiovascular Remodeling in Uninephrectomized Spontaneously Hypertensive Rats of the Stroke-Prone Strain
Authors: Orth Stephan R. , Schiele Günter , Banas Bernhard , Ritz Eberhard , Amann Kerstin
Published: September 2007

Background/Aims: The role of endothelin (ET) in cardiovascular remodeling was investigated by treating uninephrectomized spontaneously hypertensive rats of the stroke-prone strain (UNX-SHRsp) on normal- or high (3%)-salt diet with the selective ETA receptor blocker LU 135252. Methods: SHRsp on normal or high salt were sham-operated (n = 10/11) or UNX; UNX received no treatment (n = 10/15) or 100 mg/kg body weight LU 135252 (n = 10/10). Systolic blood pressure (BP) was measured weekly. After perfusion fixation the heart and the aorta were analyzed using quantitative morphological and stereological techniques. Results: No effect was seen in normal-salt groups. In high-salt animals UNX caused left ventricular (LV) hypertrophy which was prevented by LU 135252 (p < 0.001). LU 135252 only lowered BP during the last 2 weeks of the 12-week experiment. UNX showed hypertrophic remodeling of intramyocardial arterioles. Treatment with LU 135252 caused lower wall:lumen ratio and wall thickness of LV intramyocardial arterioles (p < 0.01). In the descending thoracic aorta UNX caused thickening of the media. The media area and the wall:lumen ratio were lower in UNX + LU 135252 as compared to untreated UNX (p < 0.01 and p < 0.05, respectively). Conclusion: In SHRsp UNX causes hypertrophic cardiovascular remodeling only in the presence of salt loading. These effects are largely BP-independent and prevented by ETA receptor blockade.
Platelet Activation during Haemodialysis: Comparison of Cuprammonium Rayon and Polysulfone Membranes
Authors: Thijs Abel , Grooteman Muriel P.C. , Zweegman Sonja , Nubé Menso J. , Huijgens Peter C. , Stehouwer Coen D.A.
Published: September 2007

Background/Aim: Haemodialysis-treated patients are at a high risk of developing cardiovascular disease. Part of this risk may be attributable to the type of the dialysis membrane used. We evaluated whether different dialysis membranes differ with respect to platelet activation. Methods: In a randomized crossover trial, the platelet activation was measured in 14 patients treated with two different dialyzers (cuprammonium rayon membrane and polysulfone membrane). We compared the platelet activation over the dialyzer and between dialyzers after several weeks of dialysis. Results: There were no differences between the two dialyzers in platelet activation over the dialyzer. After 2 weeks, however, the expression of CD62P, CD63, and PAC-1 was statistically significantly lower after cuprammonium membrane treatment than after polysulfone membrane treatment (mean fluorescence intensity in arbitrary units 8.0 vs. 11.1, 2.64 vs. 4.01, and 5.61 vs. 9.74, respectively). Conclusion: Dialysis with a polysulfone membrane seems to lead to more platelet activation than dialysis with a cuprammonium membrane.
Effect of Iron Loading on Peripheral Blood Lymphocyte Subsets and on Circulating Cytokine Levels in Iron-Depleted Hemodialysis Patients Receiving Erythropoietin
Authors: Tsouchnikas Ioannis , Tsilipakou Maria , Daniilidis Michalis , Kyriazis Georgios , Pasadakis Ploumis , Parapanissiou Efthymia , Vargemezis Vasilios , Tsakiris Dimitrios
Published: September 2007

Background/Aims: High doses of iron are recommended intravenously in iron-depleted hemodialysis (HD) patients receiving recombinant erythropoietin (EPO). Iron deficiency and mainly iron overload impair cellular and humoral immune response mechanisms. Imbalances in T cell subsets are common findings in disorders of iron metabolism. The aim of this study was to evaluate the effect of iron load on peripheral blood lymphocytes subsets and on circulating cytokine levels in HD iron depleted patients, treated with EPO. Methods: We studied 19 stable adult HD patients, 12 males, with a mean age 59 ± 11 years and mean HD duration 24 ± 14 months. All patients were iron deficient and were treated with unchanged EPO dose for the last 4 months before entering the study. The administered dose of iron was infused intravenously (1,000 mg iron sucrose) in 10 doses, during 10 consecutive HD sessions. Patients were screened before the commencement of the HD session on two occasions, once prior to the first dose of iron and 2 days after the 10th dose. Hematocrit (Ht), hemoglobin (Hb), iron, serum ferritin, transferrin saturation, interleukin (IL)-2, IL-4, IL-10, interferon-γ and tumor necrosis factor-α were measured. Major lymphocyte subsets (CD3+, CD19+, CD4+, CD8+, CD16+/56+, CD3+CD16+CD56+) and the ratio CD4+/CD8+ were also determined by two-color immunofluorescent analysis using flow cytometry. Results: Hb, transferrin saturation and ferritin increased significantly at the end of the study 11.2 ± 0.9 to 11.6 ± 0.8 g/dl, p < 0.005, 17.5 ± 6.9 to 23.0 ± 10.8 %, p < 0.05, and 70 ± 43 to 349 ± 194 µg/l, p < 0.005, respectively. IL-2 also increased significantly 27.8 ± 15.2 to 38.9 ± 12.8 pg/ml, p < 0.05. After iron load there was no significant change to the major lymphocyte subsets examined but a significant increase of the percentage and number of T lymphocytes with positive natural killer receptors (NKR+ T) cells was observed, 5.1 ± 3.7% to 6.3 ± 3.46%, p < 0.05, and 76.4 ± 40 to 101.5 ± 48 cells/µl, p < 0.005, respectively. Conclusion: Iron load in iron-deficient EPO-treated HD patients did not produce any changes in major lymphocyte subsets in peripheral blood, but it resulted in a significant increase of NKR+ T cells, a subpopulation important for local immune responses. Iron load for a relatively short period improved anemia of HD patients and influenced the levels of the circulating IL-2, which may regulate factors affecting the survival of patients.