Temperature Dependence of Sound Velocity and Ratio of Specific Heats in Liquids at Ultrahigh Frequencies (UHF)

Abstract

An experimental study of the central line and the Brillouin components in the molecular scattering of light has been made in several liquids using a 75 mW He-Ne gas laser as a light source. The scattered light from liquids was analyzed by a Fabry-Perot interferometer (pressure scanning) in conjunction with a dry-ice-cooled phototube detector and recorder output. Modifications in the optical system commonly used have resulted in an increased signal-to-noise ratio in the scattered radiation. In particular, a detailed study of the separation of the Brillouin doublets (to determine the UHF velocity of sound) and the ratio of the intensity of the central line to that of the doublet lines (to determine the ratio of specific heats) was made for water over a temperature range of 0° to 30°C. Correction factors for errors due to overlap of lines of central and Brillouin components are considered.