Dispersion of the Velocity of Sound in Xenon in the Critical Region

Abstract
The sound velocity in xenon on the critical isochore was determined in Brillouin scattering measurements at scattering angles of 40° and 90°. The sound dispersion calculated from our data, ultrasonic data, and other Brillouin data agrees with the Kawasaki theory for a particular choice of parameters, but the dispersion in the Brillouin velocities is 2 to 3 times smaller than the theory predicts when values obtained for the parameters from other experiments are used.