A QM MM SIMULATION METHOD APPLIED TO THE SOLUTION OF LI+ IN LIQUID-AMMONIA/

A molecular dynamics simulation method based on combined quantum mecha nical and classical potentials is proposed. This method computes the i nteractions between particles in a focus region, we call it ''Hot Spot '', at quantum chemical level within an affordable computational effor t. Application to solution chemistry was examined by simulating Lif so lvation in liquid ammonia. The new method yields a coordination number of 4 in contrast to 6 obtained from pair-potential simulation. Dynami cal properties were found in agreement with the structural change of t he solvation shell. The semi-empirical MNDO method was also tested wit hin this approach, but proved inappropriate for the treatment of elect rolyte solutions.