Surface hopping and fully quantum dynamical wavepacket propagation on multiple coupled adiabatic potential surfaces for proton transfer reactions

A general method for fully quantum mechanical wavepacket propagation on multiple adiabatic potential surfaces is developed. An analytical expression is derived for the second-derivative nonadiabatic coupling terms that arise in the adiabatic representation. Both this fully quantum mechanical wavepacket propagation method and the mixed quantum/classical surface hopping method "molecular dynamics with quantum transitions" (MDQT) are applied to a one-dimensional two-state model system for a proton transfer reaction. The remarkable agreement between the wavepacket and the MDQT methods justifies the use of MDQT for simulation of proton transfer reactions in solution.