A BORN-OPPENHEIMER APPROXIMATION FOR PATH-INTEGRALS WITH AN APPLICATION TO ELECTRON SOLVATION IN POLARIZABLE FLUIDS

The Born-Oppenheimer approximation is introduced into the path integra l expression for the canonical partition function. It is difficult to apply this to simulations. We devise a new adiabatic expression which we call the free energy Born-Oppenheimer approximation which is much e asier to simulate. It is shown that this approximation deviates from t he exact path-integral expression by no more than does the standard Bo rn-Oppenheimer approximation and we apply it to the problem of an exce ss electron dissolved in a polarizable fluid.