Role of the long-range oscillatory tail of the effective pair potential in determining the structure of liquid metals

To investigate the role of the long-range oscillatory part of the effective pair potential in determining structural features of liquid metals, the structure factor S(q) and the pair correlation function g(r) calculated for the full pair potential are compared with those obtained for various cutoff forms of the pair potential. The calculations are performed by employing the modified hypernetted-chain approximation, which is one of the best approximations in the integral equation theory of liquid. The results for liquid cesium are presented in detail. It is shown that the peak positions of g(r) and S(q) are affected rather significantly by the long-range oscillatory tail of the pair potential, the contribution from the short-range attractive part being especially important. These features are quite different from the results for the Lennard-Jones liquid, whose structure is known to be dominantly determined by the short-range repulsive part of the pair potential.