Accession Number : AD0759740

Title :   Concentration Fluctuations in the Critical Region of the Binary Liquid 3-Methylpentane-Nitroethane.

Descriptive Note : Technical rept.,

Corporate Author : MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Keyes,Paul H. ; Chang,Ren-Fang ; Sengers,Jan V. ; Alley,Carroll O.

Report Date : SEP 1972

Pagination or Media Count : 119

Abstract : The intensity and Rayleigh linewidth have been measured as a function of temperature and scattering angle for light scattered by concentration fluctuations near the critical mixing point of the binary liquid mixture 3-methylpentane-nitroethane. The data were obtained at the critical concentration above T(c) and on both sides of the coexistence curve below T(c). The susceptibility and the correlation length, xi, were determined as a function of the temperature from the intensity data. The decay rate Gamma of the concentration fluctuations was determined from the lindwidth measurements. The ratio of the correlation lengths at equal temperature intervals above and below T(c) was obtained from a comparison of both the intensity and the spectral measurements taken in these two regions. The observed variation of Gamma with K xi was compared with the theory of Kawasaki. The authors also review some recent improvements in the Kawasaki theory, reported by Kawasaki and Lo and by Perl and Ferrell, in which the viscosity is properly treated as a k and xi dependent quantity.

Descriptors :   (*ORGANIC NITROGEN COMPOUNDS, *PHASE STUDIES), CONCENTRATION(CHEMISTRY), MIXTURES, THERMODYNAMICS, VAPORIZATION, TEMPERATURE, LIGHT TRANSMISSION, SCATTERING, SOLUTIONS(MIXTURES)

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE