Hypersonic absorption of liquids determined from spontaneous and stimulated Brillouin scattering

The Brillouin linewidth at acoustic frequencies of several 10⁹Hz was measured for CS2CCl4acetone, and C6H6. 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 C6H6. 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 CS2-CCl4.