Calculating rate constants for intersystem crossing and internal conversion in the Franck–Condon and Herzberg–Teller approximations

Abstract

Effective and fast algorithms for calculating rate constants for internal conversion (IC) and intersystem crossing (ISC) in the Franck–Condon and Herzberg–Teller approximations have been developed and implemented. The methods have been employed for calculating IC and ISC rate constants for the pyrromethene-567 dye (PM567), hetero[8]circulene (4B) and free-base porphyrin (H₂P). The fluorescence quantum yields obtained by comparing calculated rate constants for the radiative and non-radiative processes are in good agreement with experimental data.