The MP/SOFT methodology for simulations of quantum dynamics: Model study of the photoisomerization of the retinyl chromophore in visual rhodopsin

Rigorous simulations of excited-state nonadiabatic quantum dynamics in polyatomic chromophores are particularly challenging since they require solving the multichannel time-dependent Schrِdinger equation describing nuclear wavepackets evolving on electronically coupled potential energy surfaces. This paper presents an overview of the matching-pursuit/split-operator-Fourier-transform (MP/SOFT) method for simulations of nonadiabatic quantum dynamics [X. Chen, V.S. Batista, Matching-pursuit split operator Fourier transform simulations of excited-state nonadiabatic quantum dynamics in pyrazine. J. Chem. Phys., 125 (2006) Art. No. 124313] and its application to the description of the 11-cis/all-trans photoisomerization of the retinyl chromophore in rhodopsin. The underlying nonadiabatic dynamics is described by a 2-state 25-dimensional wave-packet evolving according to an empirical model Hamiltonian with frequencies and excited-state gradients parameterized to reproduce the observed resonance Raman excitations of rhodopsin. The reported results show that the MP/SOFT method is a valuable tool to simulate nonadiabatic dynamics in polyatomic systems and to assess the validity of mixed quantum-classical approaches as applied to simulations of complex (nonintegrable) quantum dynamics in multidimensional systems.