Internal Field and the Additivity of Bond Polarizabilities

Abstract

The effect of internal field on the additivity of bond polarizabilities is investigated using a dipole-interaction model. An application of the theory to the isolated ethane molecule, with the aid of an high-speed computer, has demonstrated a marked dependence of bond polarizability parameters on internal field. It is shown by comparison with experimental data that there is less variation in the average bond polarizability than in the ellipticity of bond polarizability. The results suggest that the bond polarizabilities that best fit present experimental data lie in a region in the b̄CC—b̄CH domain at least as large as b̄CC=0.51±0.03 Å3 by b̄CH=0.66±0.04 Å3 with considerable uncertainty in the ellipticity.