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Femtosecond excited-state dynamics in chlorosomal carotenoids of the photosynthetic bacterium Chloroflexus aurantiacus revealed by near infrared pump–probe spectroscopyстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Yakovlev Andrei G., Taisova Alexandra S., Fetisova Zoya G.
- Журнал: Physical Chemistry Chemical Physics
- Год издания: 2021
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- DOI: 10.1039/d1cp00927c
- Аннотация: In photosynthetic green bacteria, chlorosomes provide light harvesting with high efficiency. Chlorosomal carotenoids (Cars) participate in light harvesting together with the main pigment, bacteriochlorophyll (BChl) c/d/e. In the present work, we studied the excited-state dynamics in Cars from Chloroflexus (Cfx.)aurantiacus chlorosomes by near infrared pump–probe spectroscopy with 25 fs temporal resolution at room temperature. The S2 state of Cars was excited at a wavelength of B520 nm, and the absorption changes were probed at 860–1000 nm where the excited state absorption (ESA) of the Cars S2 state occurred. Global analysis of the spectroscopy data revealed an ultrafast (B15 fs) and large (4130 nm)red shift of the S2 ESA spectrum together with the well-known S2 - S1 IC (B190 fs) and Cars - BChl c EET (B120 fs). The S2 lifetime was found to be B74 fs. Our findings are in line with earlier results on the excited-state dynamics in Cars in vitro. To explain the extremely fast S2 dynamics, we have tentatively proposed two alternative schemes. The first scheme assumed the formation of a vibrational wavepacket in the S2 state, the motion of which caused a dynamical red shift of the S2 ESA spectrum. The second scheme assumed the presence of two potential minima in the S2 state and incoherent energy transfer between them.
- Добавил в систему: Яковлев Андрей Георгиевич