CALCULATION OF THE ELECTRONIC-PROPERTIES OF NEUTRAL AND IONIZED DIVALENT-METAL CLUSTERS

The electronic properties of neutral and ionized divalent-metal clusters have been studied using a microscopic theory, which takes into account the interplay between van der Waals (vdW) and covalent bonding in the neutral clusters, and the competition between hole delocalization and polarization energy in the ionized clusters. By calculating the ground-state energies of neutral and ionized Hg(n) clusters, we determine the size dependence of the bond character and the ionization potential I(p)(n). For neutral Hg(n) clusters we obtain a transition from van der Waals to covalent behaviour at the critical size n(c) is similar to 10-20 atoms. Results for I(p)(Hg(n)) with n less-than-or-equal-to 20 are in good agreement with experiments, and suggest that small Hg(n)+ clusters can be viewed as consisting of a positive trimer core Hg3+ surrounded by n - 3 polarized neutral atoms.