Evaluation of total and partial structure factors, self-diffusion coefficients, and compressibilities of the cadmium-gallium melt

Abstract

The three partial structure factors S₁₁(K), S₂₂(K), and S₁₂(K) defined by Ashcroft and Langreth are computed with a square-well potential as a perturbation over a hard-sphere potential for different atomic fractions or concentrations of cadmium for Cd-Ga melt at 296 °C. Also, the number-number, concentration-concentration, and the cross-term number-concentration structure factors due to Bhatia-Thornton have been calculated for the seven concentrations of Cd-Ga melt at that temperature. From these partial structure factors total structure factors are computed and are compared with the experimental results. The total structure factors so computed are found to be in excellent agreement with the measured values except in the long-wavelength limit of S(0). Using the partial structure factors in the long-wavelength limit the isothermal compressibilities have been calculated. From these partial structure factors and by using the linear-trajectory approximation of Helfand, the self-diffusion coefficients D_i's have also been calculated for various atomic fractions of Cd for Cd-Ga alloy at 296°C. From these D_i's, an estimate of the mutual diffusion coefficients has been made to a good approximation.