A comparison of effective polarizabilities from electro-optical experiments using microscopic and macroscopic theories of the local electric field

Abstract

Previous theoretical results are summarized in which the microscopic fluctuation theory of Ladanyi and Keyes was extended to include the optical Kerr effect (OKE), Cotton–Mouton effect (CME), and light scattering (LS) intensities from liquids composed of asymmetric molecules. Data from the literature for these experiments is compiled and evaluated, and a comparison is made between theory and experimental results for molecules with axial and C2v symmetry. CME, OKE, and depolarized LS results are combined with harmonic generation results to obtain an estimate of the orientational pair correlations in liquids. Good agreement is found with previous determinations from dilution experiments. The results obtained from the microscopic treatment are shown to be of the same functional form as the macroscopic ellipsoidal Lorentz theory. A comparison of the results from the two theories allows a detailed examination of the microscopic approximations in the macroscopic theory. Expressions are obtained for ’’effective’’ molecular polarizabilities and hyperpolarizabilities in terms of gas phase values and cavity anisotropies.