Effective polarizabilities of n-alkanes: Intramolecular interactions in solution and in the gas phase

Abstract

The interacting atom model (IAM) of molecular polarizabilities, used previously to describe depolarized light scattering from gas phase n‐alkanes, is applied to the optical response of longer n‐alkane chains. A skeletal model of n‐alkanes is used. The effective polarizabilities, observed in dilute solution light scattering experiments, are modeled either by decreasing the atomic polarizabilities from their gas phase values or by the screening of intramolecular dipole induced dipole interactions. It is found that both of these effective polarizability IAM’s resemble more closely the bond additive effective polarizability than the ’bare’ IAM polarizability does. It is also found that the chain length dependence of effective mean squared anisotropic polarizabilities and depolarization ratios, predicted by the IAM and by the bond additive approximation (BAA), became more similar as the chain length increases. This suggests that the two models lead to the same asymptotic chain length dependence of molecular polarizabilities.