Ultrasonic absorption and velocity measurements in a critical mixture of water and phenol

Abstract

Ultrasonic absorption and velocity measurements by an improved pulse-echo technique have been made in a critical mixture of water and phenol. The measurements have been made both above and below the critical temperature Tc in the frequency range 5-65 MHz. Large ultrasonic absorption was observed in both cases. The experimental results can be fairly well explained by Fixman's theory (1962) of critical acoustic attenuation in binary liquid mixtures. The Debye short-range correlation lengths for this system are found to be 5*10-8 cm (above Tc) and 5.14*10-8 cm (below Tc).