On the atomic additivity of the zero point vibrational energy in molecules

Abstract

A simple polarized independent atom model (PIAM) is used in considering the zero point vibrational energy (ZPVE) in molecules. The PIAM involves neutral polarized atoms in their canonical hybridization states placed at the equilibrium positions. It is shown that for each atom it is possible to find an average vibrational energy, which summed over all atoms in a molecule, gives ZPVE to a very good accuracy in a large variety of small and medium size compounds. However, the additivity formula fails in large molecules yielding too low values. The reasons for this inadequacy are briefly discussed.