Weizsäcker inhomogeneity kinetic energy term for the inhomogeneous electron liquid characterising some 30 homonuclear diatomic molecules at equilibrium and insight into Teller’s theorem in Thomas–Fermi statistical theory

Abstract

A natural orbital functional theory for non-relativistic quantum chemistry due to one of us [MP] is here utilised to calculate the von Weizsäcker inhomogeneity kinetic energy at the equilibrium bond length (Re) for some 30 homonuclear diatomic molecules. Tw/N2, where N is the total number of electrons in the molecule considered, behaves remarkably simply and tends to a value very near to 1/2 for the Ge2 molecule when N = 64. This is in spite of the irregular variation of Re with N, which is inputted here from the experiment. It is then proposed that the dissociation energy De should be a functional of Tw to be sought. A start is made via the power law proposed earlier by one of us [NHM].