Femtosecond relaxation processes in Rhodobacter sphaeroides reaction centers
- Авторы: Yakovlev A.1, Shuvalov V.1,2
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Учреждения:
- Belozersky Institute of Physico-Chemical Biology
- Institute of Basic Biological Problems
- Выпуск: Том 82, № 8 (2017)
- Страницы: 906-915
- Раздел: Article
- URL: https://journals.rcsi.science/0006-2979/article/view/151448
- DOI: https://doi.org/10.1134/S0006297917080053
- ID: 151448
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Аннотация
Energy relaxation was studied with difference femtosecond spectroscopy in reaction centers of the YM210L mutant of the purple photosynthetic bacterium Rhodobacter sphaeroides at low temperature (90 K). A dynamical long-wavelength shift of stimulated emission of the excited state of the bacteriochlorophyll dimer P was found, which starts simultaneously with P* formation and is accompanied by a change in the spectral shape of this emission. The characteristic value of this shift was about 30 nm, and the characteristic time about 200 fs. Difference kinetics ΔA measured at fixed wavelengths demonstrate the femtosecond shift of the P* stimulated emission appearing as a dependence of these kinetics on wavelength. We found that the reported long-wavelength shift can be explained in terms of electron-vibrational relaxation of the P* excited state with time constants of vibrational and electronic relaxation of 100 and 50 fs, respectively. Alternative mechanisms of the dynamical shift of the P* stimulated emission spectrum are also discussed in terms of energy redistribution between vibrational modes or coherent excitation of the modes.
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Об авторах
A. Yakovlev
Belozersky Institute of Physico-Chemical Biology
Автор, ответственный за переписку.
Email: yakov@genebee.msu.su
Россия, Moscow, 119991
V. Shuvalov
Belozersky Institute of Physico-Chemical Biology; Institute of Basic Biological Problems
Email: yakov@genebee.msu.su
Россия, Moscow, 119991; Pushchino, Moscow Region, 142290
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