A New Optimization of Atom Polarizabilities in Halomethanes, Aldehydes, Ketones, and Amides by Way of the Atom Dipole Interaction Model

Abstract

A new optimization of atom polarizabilities is carried out by fitting observed mean molecular polarizabilities, polarizability anisotropies, and Kerr constants with values calculated by way of the atom dipole interaction (ADI) model which was used for similar purposes by this laboratory in 1972. New values are obtained for the polarizabilities of F, Cl, and Br in halomethanes, C‘ and O in aldehydes, ketones, and amides, H in the aldehyde C‘HO and the amide NH group, and N in amides. Most of the new values differ slightly from atom polarizabilities that were optimized to fit only observed mean polarizabilities in 1972, though differences up to 50% occur. The new values result in a considerably improved fit of calculated and observed anisotropies and Kerr constants, with a somewhat poorer fit to mean polarizabilities. The results are compared with those from studies by Birge, Thole, and Miller, who used modified versions of the ADI model. It is concluded that the unmodified model reproduces observed anistotropies about as well as any other model with the revised atom polarizabilities.