Ju n 19 97 Structural and Electronic Properties of Small Neutral ( MgO ) n Clusters

Ab initio Perturbed Ion (PI) calculations are reported for neutral stoichiometric (M gO) n (n ≤ 13) clusters. An extensive number of isomer structures was identified and studied. For the isomers of (M gO) n (n ≤ 7) clusters, a full geometrical relaxation was considered. Correlation corrections were included for all cluster sizes using the Coulomb-Hartree-Fock (CHF) model proposed by Clementi. The results obtained compare favourably to the experimental data and other previous theoretical studies. Inclusion of correlation is crucial in order to achieve a good description of these systems. We find an important number of new isomers which allows us to interpret the experimental magic numbers without the assumption of structures based on (M gO) 3 subunits. Finally, as an electronic property, the variations in the cluster ionization potential with the cluster size were studied and related to the structural isomer properties.