Nonadiabatic dynamics with spin-flip vs linear-response time-dependent density functional theory: A case study for the protonated Schiff base C5H6NH2+

Nonadiabatic trajectory surface hopping simulations are reported for trans-C5H6NH2+, a model of the rhodopsin chromophore, using augmented fewest-switches algorithm. Electronic structure calculations were performed time-dependent density functional theory (TDDFT) in both its conventional linear-response (LR) and spin-flip (SF) formulations. In SF-TDDFT case, spin contamination low-lying singlet states is removed by projecting out lowest triplet component during iterative solution TDDFT eigenvalue problem. The results show that qualitatively describes photoisomerization with favorable comparison to previous studies multireference electronic methods. contrast, LR-TDDFT affords different photodynamics due an incorrect excited-state potential near Franck–Condon region. addition, photochemistry (involving pre-twisting central double bond) appears be SF- LR-TDDFT, which may consequence conical intersection topographies afforded these two present contrast surface-hopping suggesting method’s topology around S1/S0 intersections immaterial photodynamics.