THERMODYNAMICS AND STRUCTURE OF LIQUID-METALS FROM THE SOFT SPHERE REFERENCE FLUID

The Gibbs-Bogoliubov inequality is used to compute the thermodynamics and structural properties of alkali metals and Mg, Cd, Al, In, Tl, Pb using the soft sphere (SS) reference fluid. The results are compared with earlier calculations using the charged hard sphere (CHS) as a reference fluid. It is concluded that the SS reference fluid gives better results than the CHS for the quantities investigated and yields, in all cases, lower values for the free energy, thus indicating that the SS is a preferred system: From the structural point of view, the SS predicts better agreement with experiments for the position of maxima and minima of the structure factor, although it tends to overemphasize the peaks in all cases when compared with the CHS. It is suggested on the basis of the calculations that the SS could be used for more calculations involving fluid variational perturbation approach because of its relative simplicity and ability to produce remarkably good results for structure and thermodynamics of liquid metals when computed values are compared with experiments.