Theoretical evaluation of structure factors and computation of coordination number, compressibility, and self- and mutual-diffusion coefficients of the Hg-Tl alloy

Abstract

The partial structure factors have been evaluated for the Hg-Tl amalgam. These have been computed with a hard-sphere reference system and a square-well attractive tail as a perturbation. The Libowitz solution of the direct correlation function for the hard-sphere mixtures has been used as a reference. The coordination numbers, the total structure factors, and the compressibilities of the alloy at different concentrations have been computed. The computed total structure factors are found to be in very good agreement with the measured values except at two concentrations. In addition, the thermodynamically important Bhatia-Thoronton correlation functions have been calculated. The cross-correlation function, namely the number-concentration function, did not exhibit any shoulder, thereby indicating no compound formation. The Helfand trajectory principle has been used to evaluate the self- and mutual-diffusion coefficient over the entire range of concentration for which measurements have been made. The ratio D_Hg/D_Tl is found to be constant, thereby indicating that the alloy forms a regular solution. It may be pointed out that the thermodynamic and transport properties have been computed from potential parameters of pure constituents and no experimental data of the alloy are used in these calculations.