Photoinduced Charge Transfer Dynamics in the Carotenoid–Porphyrin–C60 Triad via the Linearized Semiclassical Nonequilibrium Fermi’s Golden Rule

• Published in: The journal of physical chemistry. B 2020-10, Vol.124 (43), p.9579-9591
• Main Authors: Hu, Zhubin, Tong, Zhengqing, Cheung, Margaret S, Dunietz, Barry D, Geva, Eitan, Sun, Xiang
• Format: Article
• Language: English
• Subjects: B: Liquids, Chemical and Dynamical Processes in Solution, Spectroscopy in Solution
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/acs.jpcb.0c06306

The nonequilibrium Fermi’s golden rule (NE-FGR) describes the time-dependent rate coefficient for electronic transitions when the nuclear degrees of freedom start out in a nonequilibrium state. In this paper, the linearized semiclassical (LSC) approximation of the NE-FGR is used to calculate the photoinduced charge transfer (CT) rates in the carotenoid–porphyrin–C60 molecular triad dissolved in explicit tetrahydrofuran. The initial nonequilibrium state corresponds to impulsive photoexcitation from the equilibrated ground state to the ππ* state, and the porphyrin-to-C60 and carotenoid-to-C60 CT rates are calculated. Our results show that accounting for the nonequilibrium nature of the initial state significantly enhances the transition rate of the porphyrin-to-C60 CT process. We also derive the instantaneous Marcus theory (IMT) from LSC NE-FGR, which casts the CT rate coefficients in terms of a Marcus-like expression, with explicitly time-dependent reorganization energy and reaction free energy. IMT is found to reproduce the CT rates in the system under consideration remarkably well.