Bonded-atom properties and the inert gases

Abstract

It is shown that the mean-quare electric dipole moments that are responsible for London dispersion forces between molecules can be predicted accurately from the corresponding values for the inert gases. The procedure requires that the bonded-atom constituents of any molecule are represented by the nearest inert gas and that additional electrons, such as in π-bonds or in anions, are represented by appropriate fractions of the relevant inert gas, e.g. C₆H₆ is represented by the formula Ne_7.5He₆. In this way it is demonstrated that molecular first ionization potentials can be predicted with satisfactory precision. Alternatively, the approach can be used to elucidate molecular structure from experimental ionization potentials.