The long-wavelength behaviour of the structure factor of liquid alkali metals

The authors present results of calculations of the low-q behaviour of the liquid structure factor S(q) of the alkali metals for a wide range of thermodynamic states. Assuming that the interionic forces can be modelled by the effective pairwise potential arising in second-order pseudopotential theory, they have calculated S(q) for small q using two different random-phase approximations. The first employs a hard-sphere reference system and the second uses the one-component plasma as the reference system. The second scheme enables them to evaluate S(0) and the coefficient of q ² in S(q) analytically.