Accession Number : AD0693578

Title :   COMPOSITION FLUCTUATIONS IN TWO COMPONENT ISOTROPIC SYSTEMS.

Descriptive Note : Technical rept.,

Corporate Author : CATHOLIC UNIV OF AMERICA WASHINGTON D C VITREOUS STATE LAB

Personal Author(s) : Macedo,P. B. ; Srinivasan,G. R. ; Simmons,J. H. ; Gammell,P. M.

Report Date : JUL 1969

Pagination or Media Count : 48

Abstract : The effect of composition gradients up to fourth order in the free energy expansion for an inhomogeneous isotropic system on the intensity of electromagnetic radiation scattered from such a system is considered. An expression for the scattered intensity is derived and tested for three systems for which suitable low angle x-ray scattering data is available. It is found that the present theory satisfactorily accounts for deviations from the classical Ornstein-Zernicke-Debye behavior. The present expression for the scattered intensity is more general than that which has been obtained by expanding the Ornstein-Zernicke direct correlation function to fourth order. The temperature dependence of the free energy of the inhomogeneous fluid is also investigated and, based on the available data for the methanol cyclohexane, it is concluded that the temperature dependence of the second derivative of the free energy with respect to composition evaluated at the critical composition is the same above and below the critical temperature. (Author)

Descriptors :   (*PHASE STUDIES, *FREE ENERGY), SCATTERING, ORGANIC SOLVENTS, INTERFACES, DENSITY, X RAY DIFFRACTION, BORON COMPOUNDS, OXIDES, LEAD COMPOUNDS

Subject Categories : Physical Chemistry
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE