Theoretical studies of the interaction of H2O with small clusters of beryllium atoms

Abstract

The interaction of a water molecule with a cluster of beryllium atoms [Ben … OH2, n = 1–5] has been examined by ab initio molecular orbital methods. The dependence of interaction energy and structure on the size of the cluster was investigated with a large basis set including polarization functions. The effects of electron correlation were considered by Moller-Plesset perturbation theory. A surprisingly large increase in the interaction energy from 5 kcal/mol to 23 kcal/mol occurs when the cluster size reaches three atoms with a decrease in the Be-O distance from 1.71 to 1.64 A. The dissociation energy shows no further large changes when the cluster size is increased to four and five atoms. The H2O is found to prefer corner binding sites significantly over edge or face sites on the clusters. The nature of the bonding between H2O and the Be clusters is discussed.