Showing papers on "Hyperpolarizability published in 1971"

Higher order interaction energies for systems of asymmetric molecules

Abstract: Long-range electrical interactions in a system of N asymmetric molecules are examined in the third order of Rayleigh-Schrodinger perturbation theory. The total third-order interaction energy separates into five categories. Two of the categories correspond to classical electric induction interactions between asymmetric molecules and three of the categories correspond to dispersion-type interactions. The induction interactions consist of a set of terms which are linear in the first hyperpolarizability tensor and its generalizations and a set of terms which are bilinear in the polarizability tensor and its generalizations. One category of dispersion interactions is a generalization of the pairwise non-additive triple-dipole interaction between atoms first studied by Muto and by Axilrod and Teller. A second category of dispersion interactions, which depends on molecular hyperpolarizability tensors that also occur in the theory of the linear electro-optic effect, is non-vanishing only when at least one of the ...

Dielectric Polarization and Alignment and the Structure of Polar Fluids

Abstract: An analysis is made of the information about the structure of dense polar fluids which resides in the dielectric constant, the Kerr constant, and the nuclear magnetic resonance (NMR) quadratic electric field effect. The inadequacy of the “local‐field” model for liquids is discussed. The existence of a nonzero molecular hyperpolarizability is shown to destroy an equivalence which would otherwise exist between the Kerr and NMR experiments, and can easily account for apparent discrepancies between the reported Kerr and NMR data for nitrobenzene and nitromethane. A method is presented for removing dielectric boundary effects from statistical averages, so that the averages can be computed locally.