Global Nonadiabatic Switching Algorithm

The ab initio nonadiabatic molecular dynamics simulation is classified into two major steps; the first is to calculate electronic ground- and excited-state potential energy surfaces from various electronic quantum chemistry methods under Born–Oppenheimer approximation and the second is to formulate nonadiabatic molecular dynamics simulation based on various chemical reaction dynamic methods. Tully’s fewest nonadiabatic switching method requires to compute nonadiabatic coupling vector along on-the-fly trajectory. A new nonadiabatic switching called as global switching does not need to compute nonadiabatic coupling vector and the analytical global switching probability can be computed only with potential energy surfaces plus its gradient along on-the-fly trajectory.