Naslov
Semiclassical Approach to Photophysics Beyond Kasha’s Rule and Vibronic Spectroscopy Beyond the Condon Approximation. The Case of Azulene

Autori
Prlj, Antonio ; Begušić, Tomislav ; Zhang, Zhan Tong ; Fish, George Cameron ; Wehrle, Marius ; Zimmermann, Tomáš ; Choi, Seonghoon ; Roulet, Julien ; Moser, Jacques-Edouard ; Vaníček, Jiří

Izvornik
Journal of Chemical Theory and Computation (1549-9618) 16 (2020), 4; 2617-2626

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
wave-packet propagation, time-dependent approach, herzberg-teller, molecular-dynamics, nonadiabatic dynamics, conical intersection, quantum dynamics, optical-spectra, state decays, absorption

Sažetak
Azulene is a prototypical molecule with an anomalous fluorescence from the second excited electronic state, thus violating Kasha's rule, and with an emission spectrum that cannot be understood within the Condon approximation. To better understand the photophysics and spectroscopy of azulene and other nonconventional molecules, we developed a systematic, general, and efficient computational approach combining the semiclassical dynamics of nuclei with ab initio electronic structure. First, to analyze the nonadiabatic effects, we complement the standard population dynamics by a rigorous measure of adiabaticity, estimated with the multiple-surface dephasing representation. Second, we propose a new semiclassical method for simulating non-Condon spectra, which combines the extended thawed Gaussian approximation with the efficient single-Hessian approach. S-1 <- S-0 and S-2 <- S-0 absorption and S-2 -> S(0 )emission spectra of azulene, recorded in a new set of experiments, agree very well with our calculations. We find that accuracy of the evaluated spectra requires the treatment of anharmonicity, Herzberg-Teller, and mode-mixing effects.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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