Toward an ab initio treatment of the time-dependent Schrodinger equation of molecular systems

The time-dependent variational principle (TDVP) is employed to produce equa tions of motion that approximate the time-dependent Schrodinger equation. C hoices of wave function and basis sets are discussed. The use of electron t ranslation factors and the electronic and nuclear parts of the molecular wa vefunction are put in the context of the electron nuclear dynamics (END) th eory. The role of wave function parameters as dynamical variables is discus sed, and the use of coherent state parametrization is explored.