A Phase-Space Semiclassical Approach for Modeling Nonadiabatic Nuclear Dynamics with Electronic Spin

TL;DR

This paper introduces a phase-space semiclassical method for modeling nonadiabatic nuclear dynamics involving electronic spin, capable of handling complex Hamiltonians with Berry curvature effects, spin-orbit coupling, and magnetic fields.

Contribution

It develops a novel surface hopping approach on phase-space adiabatic surfaces for complex Hamiltonians, extending semiclassical nonadiabatic dynamics modeling to include spin effects.

Findings

Valid in both adiabatic and nonadiabatic regimes

Incorporates Berry curvature effects

Handles spin-orbit coupling and magnetic fields

Abstract

Chemical relaxation phenomena, including photochemistry and electron transfer processes, form a vigorous area of research in which nonadiabatic dynamics plays a fundamental role. Here, we show that for nonadiabatic dynamics with two electronic states and a complex-valued Hamiltonian that does not obey time-reversal symmetry, the optimal semiclassical approach is to run surface hopping dynamics on a set of phase-space adiabatic surfaces. In order to generate such phase-adiabats, one must isolate a proper set of diabats and apply a phase gauge transformation, before eventually diagonalizing the total Hamiltonian (which is now parameterized by both R and P). The resulting algorithm is valid in both the adiabatic and nonadiabatic limits, incorporates all Berry curvature effects, and allows for the study of semiclassical nonadiabatic dynamics in the presence of spin-orbit coupling and/or external magnetic fields.