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 &#957;(CO) and &#957;(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 &#957;(CO) band positionsoccur with change from fluid to rigid solvent-&#8220;infrared rigidochromism&#8221;. There is oftena change in &#957;(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.

J. J. Turner

M. W. George

I. P. Clark

I. G. Virrels

Excited States and Intermediatesby Time-Resolved InfraredSpectroscopy

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.

Yasushi  Koyama

Leenawaty  Limantara

Tokutake  Sashima

Transient Raman Spectroscopyof Isotope-Substituted Speciesof Bacteriochlorophyll a,Bacteriopheophytin a AndChlorophyll a: Changes in theBond Orders in the MacrocyclesUpon Triplet and SingletExcitation

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 &#946;-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 &#8216;Nature knows Best&#8217; since semisyntheticantibiotics, designed to be resistant to hydrolysis by &#946;-lactamases, hydrogenbond more weakly and the acylenzymes hydrolyse more rapidly.

C. W. Wharton

M. G. P. Page

R. S. Chittock

T. E. Regan

S.  Ward

Infrared Spectroscopy of EnzymeReaction Intermediates

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.

Boris  Akhremitchev

Chengfei  Wang

Gilbert C. Walker

Ultrafast Infrared and VisibleSpectroscopy of IntermolecularElectron Transfer From DimethylAniline to Coumarin 337

Dynamics subsequent to the electronic excitation of 9,9&#8242;-bianthryl produce a polaremissive excited state for which the symmetry of the bichromophore is broken by adynamic solvent stabilisation of one of the two, otherwise degenerate, charge transferconfigurations which contribute to the excited electronic state. The initial state createdupon excitation is examined here by analysis of ground state resonance Ramanexcitation profiles (REPs) and electronic absorption spectra in solvents of variouspolarities. The results suggest that the REPs are signalling electronic differences betweenthe initially excited state in the various solvents. We suggest that this is related to thebianthryl excited state being responsive to the disordered solvent environment.

Gregory D. Scholes

Thierry  Fournier

David  Phillips

Anthony W. Parker

Solvent-Dependent ResonanceRaman Excitation Profiles of9,9&#39;-Bianthryl

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.

Xuehua  Hu

Thomas G. Spiro

Construction of 40 NanosecondTime Resolusion Step-Scan FtirDifference Spectrometer

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.

Darin J. Ulness

Michael J. Stimson

Jason C. Kirkwood

A. C. Albrecht

Time-Frequency ResolvedCoherent Raman ScatteringFrom Molecular Liquidsand Their Mixtures With Quasi-CwNoisy Light: I(2) CRS Spectrograms

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<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>&#x03B1;</mml:mi></mml:msub></mml:mrow></mml:math>&#8212;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>m</mml:mi></mml:msub></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>&#x03B2;</mml:mi></mml:msub></mml:mrow></mml:math>&#8212;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>&#x03B2;</mml:mi></mml:msub></mml:mrow></mml:math> bonds in the excited state, and that the observed differences aremainly due to the larger core-sized heme having a decreased <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>&#x03B1;</mml:mi></mml:msub></mml:mrow></mml:math>&#8212;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mi>m</mml:mi></mml:msub></mml:mrow></mml:math> force constant andlarger excited state porphyrin ring expansion.

Thomas S. Rush

Ranjit  Kumble

Modeling the Transient Changesin the Soret-Resonant RamanIntensities of Hemoglobin DuringThe R&#8594; T Transition

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 (&#957;3:2730cm-1) was determined to be43&#177;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 (&#8776;15 ps) and it was assigned as the overtone between &#957;3 mode andvibrationally excited &#957;1 mode (2620 cm-1).

Tatsuya  Fujino

Akihide  Wada

Satoru S. Kano

Kazunari  Domen

Chiaki  Hirose

Transient Absorption Spectra ofVibrationally Excited WaterMolecule on Zeolite Surface

The carbonate radical (<mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mtext>3</mml:mtext><mml:mrow><mml:msup><mml:mo>&#x2212;</mml:mo><mml:mo>&#x00B7;</mml:mo></mml:msup></mml:mrow></mml:msubsup></mml:mrow></mml:math>) 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 <mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mtext>3</mml:mtext><mml:mrow><mml:msup><mml:mo>&#x2212;</mml:mo><mml:mo>&#x00B7;</mml:mo></mml:msup></mml:mrow></mml:msubsup></mml:mrow></mml:math>, nanosecond timeresolved
resonance Raman (TR3) experiments were undertaken. Photolysis of
persulphate at 250 nm generated the <mml:math id="E4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>So</mml:mtext></mml:mrow><mml:mtext>4</mml:mtext><mml:mrow><mml:msup><mml:mo>&#x2212;</mml:mo><mml:mo>&#x00B7;</mml:mo></mml:msup></mml:mrow></mml:msubsup></mml:mrow></mml:math> radical which then oxidised sodium carbonate.
Resonance Raman spectra of the resulting <mml:math id="E5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mtext>3</mml:mtext><mml:mrow><mml:msup><mml:mo>&#x2212;</mml:mo><mml:mo>&#x00B7;</mml:mo></mml:msup></mml:mrow></mml:msubsup></mml:mrow></mml:math> 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 <mml:math id="E6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>C</mml:mtext><mml:mrow><mml:mtext>2</mml:mtext><mml:mi>v</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>
 molecular symmetry.

Susan M. Tavender

Steven A. Johnson

Daniel Balsom

Roger H. Bisby

The Carbonate, <svg style="vertical-align:-3.39069pt" height="20.875" version="1.1" viewBox="0 0 30.525 20.875" width="30.525" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,16.588)"><path id="x43" d="M614 175l29 -10q-33 -109 -57 -154q-121 -26 -184 -26q-90 0 -160.5 29t-112.5 77t-63.5 105.5t-21.5 119.5q0 157 108 253t277 96q36 0 71.5 -5t69 -13.5t36.5 -8.5q15 -102 20 -150l-29 -8q-20 79 -66.5 114t-128.5 35q-119 0 -187.5 -86t-68.5 -207&#xA;q0 -140 73.5 -227.5t188.5 -87.5q73 0 119.5 37.5t86.5 116.5z" /></g><g transform="matrix(.017,-0,0,-.017,11.605,16.588)"><path id="x6F" d="M257 449q92 0 154 -65t62 -158q0 -112 -67 -175t-150 -63q-98 0 -158.5 66.5t-60.5 154.5q0 59 21 106.5t54.5 75.5t71 43t73.5 15zM244 416q-48 0 -81 -47t-33 -128q0 -96 38 -158t99 -62q51 0 82 43.5t31 139.5q0 91 -36 151.5t-100 60.5z" /></g><g transform="matrix(.012,-0,0,-.012,20.287,8.437)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g><g transform="matrix(.008,-0,0,-.008,27.275,2.725)"><path id="x22C5" d="M170 255q0 -25 -16 -41t-40 -16t-40 16t-16 41t16 41.5t40 16.5t40 -16.5t16 -41.5z" /></g><g transform="matrix(.012,-0,0,-.012,20.287,20.675)"><path id="x33" d="M285 378v-2q65 -13 102 -54.5t37 -97.5q0 -57 -30.5 -104.5t-74 -75t-85.5 -42t-72 -14.5q-31 0 -59.5 11t-40.5 23q-19 18 -16 36q1 16 23 33q13 10 24 0q58 -51 124 -51q55 0 88 40t33 112q0 64 -39 96.5t-88 32.5q-29 0 -64 -11l-6 29q77 25 118 57.5t41 84.5&#xA;q0 45 -26.5 69.5t-68.5 24.5q-67 0 -120 -79l-20 20l43 63q51 56 127 56h1q66 0 107 -37t41 -95q0 -42 -31 -71q-22 -23 -68 -54z" /></g></svg>, in Solution Studied by Resonance Raman Spectroscopy

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Laser Chemistry | Hindawi

Laser Chemistry

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Papers are published upon acceptance, regardless of the Special Issue publication date.

Laser Chemistry

Proceedings of the Eighth Conference on Time-Resolved Vibrational Spectroscopy

Proceedings of the Eighth Conference on Time-Resolved Vibrational Spectroscopy

Articles

Excited States and Intermediates by Time-Resolved Infrared Spectroscopy

Transient Raman Spectroscopy of Isotope-Substituted Species of Bacteriochlorophyll a, Bacteriopheophytin a And Chlorophyll a: Changes in the Bond Orders in the Macrocycles Upon Triplet and Singlet Excitation

Infrared Spectroscopy of Enzyme Reaction Intermediates

Ultrafast Infrared and Visible Spectroscopy of Intermolecular Electron Transfer From Dimethyl Aniline to Coumarin 337

Solvent-Dependent Resonance Raman Excitation Profiles of 9,9'-Bianthryl

Construction of 40 Nanosecond Time Resolusion Step-Scan Ftir Difference Spectrometer

Time-Frequency Resolved Coherent Raman Scattering From Molecular Liquids and Their Mixtures With Quasi-Cw Noisy Light: I⁽²⁾ CRS Spectrograms

Modeling the Transient Changes in the Soret-Resonant Raman Intensities of Hemoglobin During The R→ T Transition

Transient Absorption Spectra of Vibrationally Excited Water Molecule on Zeolite Surface

The Carbonate, , in Solution Studied by Resonance Raman Spectroscopy