Studies on Excess Ultrasonic Absorption in Critical Binary Mixtures

Abstract

F. r a the. retical treatment, f excess ultras, nie abs, rpti, n due t, critica uctuation, lhe reported that, the ftequency dependence of sound absorptien coefficient predicted by Fixman was appropriate to compare it quantitatively with the experimental data.In his study, the frequency dependence of sound absorption coellfieient was determined concerning critical binary mixtures above critical temperature. As the comparison of the relaxationr parameter (arialyzed by the Fixman theory) in critical binary aqueous mixture with that in non-aqueous mixture was of interest, the five systems (acetnitrile-water, triethylaminer water, diethylenglycoldiethylether-water, n-hexane-nitrobenzene and n-octane-nitrobenzene) were prepared.As the experimental results on the above systems supported the Fixman prediction, they were analyzed in terms of the Fixman theory, The results of relaxation parameter (in Table 2)sh, wed that the characteristic frequency due t, the decay rate of ctuati, n in critical binary aqueous mixtures was smaller than that in non-aqueous mixtures. These results were also supperted by the molecular parameter (in Table 4) based on the temperature dependence of sound absorption.