Complete electron nuclear dynamics

The Electron nuclear dynamics (END) theory is a time-dependent, nonadiabati c approach to molecular processes. It has been implemented in the ENDyne co de at the level of approximation that treats the nuclei as classical partic les and represents the electrons with a single complex spin unrestricted de terminant. This level of theory has been successfully applied to a wide ran ge of ion-atom and ion-molecule reactive collisions. In this paper the exte nsions of the END theory are outlined in some detail through a hierarchy of approximations to the level of full quantum mechanical treatment of all pa rticipating particles.