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
.