Brillouin scattering measurements of the temperature dependence of sound velocity and acoustic absorption in simple alcohols

A scanning Fabry–Perot interferometer was used to measure Brillouin spectra of methanol, isopropanol and a 95% ethanol–water mixture for temperatures ranging between 285?K and 320?K. The Brillouin frequency shifts and linewidths were used to calculate the velocities and absorption coefficients of hypersonic acoustic waves in these liquids. The temperature dependence of sound speed and acoustic attenuation was determined. For all three materials, both sound velocity and absorption coefficient decreased with temperature.