FSSH-2: Fewest Switches Surface Hopping with Robust Switching Probability

J Chem Theory Comput. 2024 May 14;20(9):3413-3419. doi: 10.1021/acs.jctc.4c00089. Epub 2024 May 2.

Abstract

This study introduces the FSSH-2 scheme, a redefined and numerically stable adiabatic Fewest Switches Surface Hopping (FSSH) method for mixed quantum-classical dynamics. It reformulates the standard FSSH hopping probability without using nonadiabatic coupling vectors and allows for numerical time integration with larger step sizes. The advantages of FSSH-2 are demonstrated by numerical experiments for five different model systems in one and two spatial dimensions with up to three electronic states.