HYBRID PROCEDURE OF THE AB-INITIO MOLECULAR-ORBITAL (MO) METHOD AND THE MONTE-CARLO SAMPLINGS - APPLICATION TO CLUSTER B+(H2O)

The hybrid procedure of the ab initio molecular orbital (MO) method an d the Monte Carlo (MC) samplings which we have developed recently is a pplied to one to one complex of boron cation and water molecule B+(H2O ). In the present ab initio MO-MG samplings, no analytical potential f unction is assumed, and the ab initio MO method is directly used for e nergy calculation at each step. As the result of using the new method, the many body interaction is explicitly taken into the assumption, an d the chemical reaction involving the rearrangement of arbitrary atoms can be easily treated. In the case of cluster B+(H2O), no intracluste r reaction takes place, but structure under the thermal equilibrium is slightly broken from the optimised geometry. The deformation of struc ture is attributed to the entropy effect, and it is also considered a symptom of the insertion reaction B+(H2O) --> HBOH+. (C) 1998 Elsevier Science B.V. All rights reserved.