Chemical timing. 1. A method of picosecond fluorescence spectroscopy for the study of intramolecular vibrational redistribution

Coveleskie, R. A.; Dolson, David A.; Parmenter, C. S.

doi:10.1021/j100250a019

Cited by 68 publications

(27 citation statements)

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“…This competition between quenching and vibrational relaxation is a well-understood aspect of the method. 6 The analysis of chemically timed spectra has been discussed elsewhere. 6 Briefly, the spectra are divided into structured and unstructured components, the two components are integrated, and pressure intercept of the best fit curve is indicated by an X.…”

Section: Resultsmentioning

confidence: 99%

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A time-resolved fluorescence observation of intramolecular vibronic redistribution within the channel three region of S1 benzene

Moss¹,

Parmenter²

1986

J. Phys. Chem.

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Chemical timing has been used to obtain time-resolved fluorescence spectra from the vibronic levels 6112 3 and 71 within the channel three region of S, benzene. The spectra in each case reveal a dynamic IVR with an initial dephasing time on the order of tens of picoseconds. These results are consistent with previous estimates of rovibronic state decay rates from absorption line widths. The measured IVR rates are approximately two orders of magnitude faster than the electronic state decay observed from the same levels by fluorescence measurements.

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Section: Resultsmentioning

confidence: 99%

“…6 The analysis of chemically timed spectra has been discussed elsewhere. 6 Briefly, the spectra are divided into structured and unstructured components, the two components are integrated, and pressure intercept of the best fit curve is indicated by an X. The parameters km, N, and kv derived from the fits are presented in Table I.…”

Section: Resultsmentioning

confidence: 99%

A time-resolved fluorescence observation of intramolecular vibronic redistribution within the channel three region of S1 benzene

Moss¹,

Parmenter²

1986

J. Phys. Chem.

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“…In this sense, the present reliance of the experiment on collisional cooling to probe intramolecular dynamics bears some resemblance with the chemical timing experiments of Parmenter and co-workers. [23][24][25][26][27] The cooling collisions complicate the theoretical modeling of the hole-filling experiment because the temperature and collision frequency are changing as the expansion occurs.…”

Section: The Role Of Cooling Collisions On the Intramolecular Dynamentioning

confidence: 99%

The dynamics of conformational isomerization in flexible biomolecules. I. Hole-filling spectroscopy of N-acetyl tryptophan methyl amide and N-acetyl tryptophan amide

Dian

Longarte

Winter

et al. 2004

The Journal of Chemical Physics

141

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The conformational isomerization dynamics of N-acetyl tryptophan methyl amide (NATMA) and N-acetyl tryptophan amide (NATA) have been studied using the methods of IR-UV hole-filling spectroscopy (HFS) and IR-induced population transfer spectroscopy (IR-PTS), which were developed for this purpose. Single conformations of these molecules were selectively excited in well-defined NH stretch fundamentals. This excess energy was used to drive conformational isomerization. By carrying out the infrared excitation early in a supersonic expansion, the excited molecules were recooled into their zero-point levels, partially refilling the hole created in the ground state population of one of the conformers, and creating gains in population in other conformers. These changes in population were detected using laser-induced fluorescence downstream in the expansion. In HFS, the IR wavelength is fixed and the UV laser tuned in order to determine where the population went following selective infrared excitation. In IR-PTS, the UV is fixed to monitor the population of a given conformation, and the IR is tuned to record the IR-induced changes in the population of the monitored conformer. Besides demonstrating the capability of the experiment to change the downstream conformational population distribution, the IR-PTS scans were used to extract two quantitative results: (i) The fractional populations of the conformers in the absence of the infrared, and (ii) the isomerization quantum yields for each of the six unique amide NH stretch fundamentals (three conformers each with two amide groups). The method for obtaining quantum yields is described in detail. In both NATMA and NATA, the quantum yields show modest conformational specificity, but only a hint of vibrational mode specificity. The prospects for the hole-filling technique for providing insight into energy flow in large molecules are discussed, leaving a more detailed theoretical modeling to the adjoining paper [Evans et al. J. Chem. Phys. 120, 148 (2004)].

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“…Chemical timing experiments, 155 which disperse the fluroescence from vibronic state selectively excited molecules immersed in a variable pressure of O 2 quencher gas, allow the measurement of intramolecular vibrational energy redistribution times from a Franck-Condon bright mode into coupled vibrational states of the bath. Recent experiments 156 have shown that when one replaces one of the F atoms in p-diflurobenzene with a methyl group, the dephasing of the bright mode occurs 40 times faster.…”

Section: Elucidating the Transition From Mode-selective To Statisticamentioning

confidence: 99%

Photodissociation Dynamics

1996

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Chemical timing. 1. A method of picosecond fluorescence spectroscopy for the study of intramolecular vibrational redistribution

Cited by 68 publications

References 1 publication

A time-resolved fluorescence observation of intramolecular vibronic redistribution within the channel three region of S1 benzene

A time-resolved fluorescence observation of intramolecular vibronic redistribution within the channel three region of S1 benzene

The dynamics of conformational isomerization in flexible biomolecules. I. Hole-filling spectroscopy of N-acetyl tryptophan methyl amide and N-acetyl tryptophan amide

Photodissociation Dynamics

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