Second-order Møller-plesset calculations of total ground-state energies of tetrahedral and octahedral molecules at equilibrium, confronted with some model-dependent scaling properties

Using second-order Møller-Plesset (MP2) optimized geometries, calculations of total energies of some 20 tetrahedral and octahedral molecules have been carried out. We have then confronted these first-principles results, which of course include a fraction of the electronic correlation energy, with some model-dependent scaling properties. In particular, one scaling relation emerging from the semiclassical Thomas-Fermi electron density method relates the known nuclear-nuclear potential energy, V_nn, at equilibrium to the electron-nuclear term, V_en, and the total kinetic energy.