Ultrasonic study of critical behavior in the binary liquid 3-methylpentane + nitroethane
Abstract
The acoustic velocity and attenuation have been measured in a critical mixture of 3-methylpentane + nitroethane over the frequency range 1–17 MHz and the temperature range 0.004≤T−Tc≤13.5 K. No critical dispersion was observed in the velocity, which varied linearly with T. A substantial critical attenuation was well characterized as a function of the reduced frequency ω*≡ω/ωD over the range 10−1≤ω*≤106. The experimental data in this system are extensive enough to permit quantitative tests of the predictions of dynamic scaling theory, dynamic renormalization-group theory, and several versions of mode-coupling theory. Universality in the scaling function for the critical attenuation is demonstrated by comparison with comparable experimental results in two pure fluids.