Hypersonic absorption of liquids determined from spontaneous and stimulated Brillouin scattering

The Brillouin linewidth at acoustic frequencies of several 10 9 Hz was measured for CS 2 CCl 4 acetone, and C 6 H 6 . Experimental data were compared with values calculated from the theory of sound propagation under the assumption of a single relaxation frequency. Good agreement was found for the pure liquids except for C 6 H 6 . Extending a theory of binary mixtures from ultrasonic to hypersonic frequencies, we were able to account for the experimentally determined Brillouin linewidths in the mixed system CS 2 -CCl 4 .