TIME-DEPENDENT VARIATIONAL PRINCIPLE FOR NONLINEAR HAMILTONIANS AND ITS APPLICATION TO MOLECULES IN THE LIQUID-PHASE

The formulation of the time-dependent Frenkel variational principle fo r Hamiltonians containing a term depending on the wave function is her e considered. Starting from the basic principles, it is shown that it requires the introduction of a related functional, G, which, for the s ystems we are considering, has the status of a free energy. An explici t use of functional G as starting point to obtain variational wave fun ctions makes it easier to implement computational methods for a variet y of physical and chemical problems in solution, the first one among t hem being the calculation of frequency-dependent nonlinear optical pro perties of components of the liquid phase. A concise overview of appli cations of this approach which are presently being worked out in our l aboratory is also given. (C) 1996 John Wiley & Sons, Inc.