Excited-State Vibrational Coherence and Anisotropy Decay in the BacteriochlorophyllaDimer Protein B820
| Autor: | Bradley J. Homoelle, Maurice D. Edington, William M. Diffey, Warren F. Beck |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 102:2776-2786 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp9723022 |
| Popis: | We have employed dynamic absorption spectroscopy to monitor coherent wave packet dynamics and anisotropy decays following impulsive excitation of the B820 subunit of the LH1 light-harvesting complex, which was isolated from Rhodospirillum rubrum G9. When the lower exciton-state transition of the bacteriochlorophyll a dimer is pumped, the time-resolved pump−probe spectrum exhibits contributions from a fully Stokes shifted stimulated-emission spectrum and a nonstationary vibrational character within 40 fs of excitation. Coherent wave packet motion in both the ground state and the excited state is observed via modulations of single-wavelength transients. The photobleaching portion of the spectrum exhibits strong components only at low frequencies, 20−60 and 180 cm-1, and a weaker component is observed at 400 cm-1. The stimulated-emission portion of the spectrum exhibits weak modulation components at 20−60 and 180 cm-1, but strong components are observed at fairly high frequencies: 360, 400, 470, 600, and 73... |
| Databáze: | OpenAIRE |
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