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. (C) 1997 Elsevier Science B.V.