[Back to Issue 10 ToC] [Back to Journal Contents] [Back to Biochemistry (Moscow) Home page]

Comparative Absorption Dynamics of the Singlet Excited States of Chlorophylls a and d

Dmitry A. Cherepanov1,2,a*, Anastasia A. Petrova2, Mahir D. Mamedov2, Anna I. Vishnevskaya2, Fedor E. Gostev1, Ivan V. Shelaev1,2, Arseniy V. Aybush1, and Victor A. Nadtochenko1,3

1N. N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia

2A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia

3Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia

* To whom correspondence should be addressed.

Received March 17, 2022; Revised April 19, 2022; Accepted May 6, 2022
Transient absorption dynamics of chlorophylls a and d dissolved in tetrahydrofuran was measured by the broadband femtosecond laser pump-probe spectroscopy in a spectral range from 400 to 870 nm. The absorption spectra of the excited S1 singlet states of chlorophylls a and d were recorded, and the dynamics of the of the Qy band shift of the stimulated emission (Stokes shift of fluorescence) was determined in a time range from 60 fs to 4 ps. The kinetics of the intramolecular conversion Qx→Qy (electronic transition S2→S1) was measured; the characteristic relaxation time was 54 ± 3 and 45 ± 9 fs for chlorophylls a and d, respectively.
KEY WORDS: chlorophyll a, chlorophyll d, femtosecond laser spectroscopy, excited state spectrum, Stokes shift dynamics, internal conversion

DOI: 10.1134/S000629792210011X