QUANTUM-MECHANICAL STUDY OF THE STRUCTURE AND STABILITY OF MOLECULAR VAN-DER-WAALS CLUSTERS-I - HYDRATES OF SO(2)

The structure and stability of the mixed clusters SO2(H2O)n, n ranging from 1 to 4, have been examined using semi-empirical quantum mechanic al Hartree Fock methods with the unproved PM3 parameter set as impleme nted in MOPAC [1]. Limited molecular dynamics studies together with in vestigation of the potential surface reveal potential barriers of 1kca l/mol or less between many of the stable structures for a cluster of a given size. For n=1,2 the results are compared with those of ab initi o calculations using a double zeta basis at the MP4 level.