Theory of the static Kerr effect in dense fluids

Abstract

A general expression, independent of the shape of the sample, is derived for the static Kerr constant, κ, of a dense fluid of optically anisotropic, nonpolar molecules. The molecules are assumed to have second-rank tensorial polarizabilities and fourth-rank tensorial hyperpolarizabilities. This expression for κ is expanded in powers of the ‘cut-out’ dipole propagator. The first non-trival term in the expansion is analysed in terms of the pair-distribution function. The resulting expression for the Kerr constant is compared to the depolarized scattering intensity, I _dep, obtained to the same level of approximation. Similarities and differences between these quantities are discussed and predictions about the behaviour of the Kerr constant for dense fluids are made on the basis of numerical results obtained earlier for I _dep. κ is expressed in terms of ‘effective’ polarizability anisotropies and hyperpolarizability, different from their gas-phase counterparts. It is found that the dipole-induced-dipole interactions influence the Kerr constant strongly at liquid densities. It is also found that a simple relation between the hyperpolarizability independent part of κ and I _dep does not exist in the case of dense fluids.

Supported in part by the National Science Foundation (NSF Grant CHE76-07384).

Supported in part by the National Science Foundation (NSF Grant CHE76-07384).

Notes

Supported in part by the National Science Foundation (NSF Grant CHE76-07384).

Additional information

Notes on contributors

T. Keyes

Alfred P. Sloane Foundation Fellow.