Quantum mechanical studies of atomic, bond, and molecular polarizabilities: Application to molecules having four to eight residual atomic polarizability degrees of freedom

Abstract

Various quantum mechanical models hitherto developed for calculating the atomic and molecular polarizabilities, and assessing the extent to which the polarizability could be a useful criterion for testing the utility of the wave functions chosen have been briefly surveyed. The delta-function potential model based on the variational method and delta-function electronic wave functions has been described, and then applied to obtain the necessary derivations for the atomic polarizability, bond parallel component, bond perpendicular component, contribution by the nonbonding electrons, and average molecular polarizability. The Lewis—Langmuir octet rule, modified by Linnett as a double quartet of electrons, has been employed for such investigations. Atomic, bond, and molecular polarizabilities have been computed for many diatomic and polyatomic molecules having four, five, six, seven, and eight residual atomic polarizability degrees of freedom. The available experimental values of molecular polarizabilities for many of the molecules studied here are in good agreement with those calculated on the basis of the delta-function potential model. The results have been discussed in relation to the nature of various characteristic bonds, distribution of the electrons, and the configurations of the molecular systems.