Ultrasonic study of critical behavior in the binary liquid 3hyphen;methylpentanethinsp;+thinsp;nitroethane

摘要

The acoustic velocity and attenuation have been measured in a critical mixture of 3hyphen;methylpentanethinsp;+thinsp;nitroethane over the frequency range 1ndash;17 MHz and the temperature range 0.004le;Tminus;Tcle;13.5 K. No critical dispersion was observed in the velocity, which varied linearly withT. A substantial critical attenuation was well characterized as a function of the reduced frequency ohgr;ast;equiv;ohgr;/ohgr;Dover the range 10minus;1le;ohgr;ast;le;106. The experimental data in this system are extensive enough to permit quantitative tests of the predictions of dynamic scaling theory, dynamic renormalizationhyphen;group theory, and several versions of modehyphen;coupling theory. Universality in the scaling function for the critical attenuation is demonstrated by comparison with comparable experimental results in two pure fluids.