SHARC: ab Initio Molecular Dynamics with Surface Hopping in the Adiabatic Representation Including Arbitrary Couplings

摘要

We present a semiclassical surface-hopping method which is able to treat arbitrary couplings in molecular systems includingall degrees of freedom. A reformulation of the standard surface-hopping scheme in terms of a unitary transformation matrixallows for the description of interactions like spin-orbit coupling or transitions induced by laser fields. The accuracy ofour method is demonstrated in two systems. The first one, consisting of two model electronic states, validates thesemiclassical approach in the presence of an electric field. In the second one, the dynamics in the IBr molecule in thepresence of spin-orbit coupling after laser excitation is investigated. Due to an avoided crossing that originates from spin-orbit coupling, IBr dissociates into two channels: I + Br(~2P_(3/2)) and I + Br~*(~2P_(1/2)). In both systems, the obtainedresults are in very good agreement with those calculated from exact quantum dynamical simulations.