Partial structure factors and diffusion coefficients of liquid potassium-cesium alloys.

Abstract

With use of the square-well potential as a perturbation on the hard-sphere potential, the partial structure factors defined by Ascroft and Langreth [Phys. Rev. 159, 500 (1967)] and also the number-number, number-concentration, and concentration-concentration structure factors of Bhatia and Thornton [Phys. Rev. 32, 3004 (1970)] are calculated for liquid potassium-cesium alloys at various concentrations at 100 \ifmmode^\circ\else\textdegree\fi{}C. From the partial structure factors, the total structure factors are also calculated and compared with experimental values. The hard-sphere values are also computed for the same concentrations. The difference plots of the total structure factors of the square well and those of the hard spheres are also presented. The total structure factors obtained from these partial structure factors in the long-wavelength limit are used to calculate the isothermal compressibilities. With the partial structure factors and using Helfand's prescription extended by Davies and Polyvos, we calculate the self-diffusion coefficients. From the self-diffusion coefficients, an estimate of the mutual diffusion coefficients has been made to a good approximation.