Energy dissipation in the ground-state vibrational manifolds of beta-carotene homologues: a sub-20-fs time-resolved transient grating spectroscopic study

Fujiwara, M., Yamauchi, K., Sugisaki, M., Gall, A., Robert, B., Cogdell, R.J. and Hashimoto, H. (2008) Energy dissipation in the ground-state vibrational manifolds of beta-carotene homologues: a sub-20-fs time-resolved transient grating spectroscopic study. Physical Review B, 77(20), p. 205118. (doi:10.1103/PhysRevB.77.205118)

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Publisher's URL: http://dx.doi.org/10.1103/PhysRevB.77.205118

Abstract

Transient grating (TG) signals in 8-carotene homologues, by using sub-20-fs excitation pulses, were measured in order to investigate the dependence of the vibrational coherence dynamics on the pi-conjugation length of these carotenoids. The experimental TG traces can be well reproduced by computational simulations based on a Brownian oscillator model using the spectral density determined from their respective resonance Raman spectra and their previously reported excited-state population-relaxation times. The total dephasing times of the ground-state vibrational modes of the homologues were determined by applying a wavelet transformation of their coherent oscillations, which were observed in the experimental TG traces. The total dephasing time decreases as the number of conjugated C=C double bonds increases. The decoherence of the ground-state vibrational modes in the homologues is mainly caused by system-bath interactions. The dephasing time of the C-C stretching modes strongly depends on the conjugation length, whereas that of the C=C stretching does not. This trend clearly shows that shorter-chain carotenoids have a specific major channel of energy dissipation to the environment (the C=C stretching), whereas the longer-chain carotenoids do not

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cogdell, Professor Richard
Authors: Fujiwara, M., Yamauchi, K., Sugisaki, M., Gall, A., Robert, B., Cogdell, R.J., and Hashimoto, H.
Subjects:Q Science > QC Physics
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Physical Review B
Publisher:American Physical Society
ISSN:1098-0121
ISSN (Online):1550-235X

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