Second-Order Moller-Plesset Calculations of Total Ground-State Energies of Tetrahedral and Octahedral Molecules at Equilibrium, Confronted with Some Model-Dependent Scaling Properties

Using second-order Moller-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.