Effect of Pressure and Temperature Upon the Optical Dispersion of Benzene, Carbon Tetrachloride and Water

Abstract

An interferometer has been used to measure the change in index of refraction with change in pressure or temperature. Absolute indices of refraction are reported to five decimals for benzene, carbon tetrachloride, and water at eight different wavelengths in the visible region of the spectrum at pressures as high as 1100 bars and temperatures as high as 55 °C. The data for benzene and carbon tetrachloride have been fitted to one term, dispersion equations of the Drude and Lorentz-Lorenz types. The observed changes in index of refraction for these two liquids have been attributed to change in density plus a shift in the fundamental absorption frequency, assuming that the oscillator strength remains constant. The data for water have been treated and explained in the same manner but with the additional postulate that water consists of two different molecular types.