Band model for the electronic structure of expanded liquid cesium

Self-consistent, scalar-relativistic, linear-augmented-plane-wave calculations have been carried out for four (real and hypothetical) crystalline forms of cesium with the body-centered-cubic, simple-cubic, simple-tetragonal, and diamond structures at a fixed nearest-neighbor bond distance. The results of these calculations are applied to model the variation with density of several one-electron properties of expanded liquid cesium, including the total density of states N(EF), its $6s$ component Nₛ(EF), and the average Fermi-electron charge density at the nucleus. The calculations fail to explain an observed enhancement of the magnetic susceptibility at low densities. Also, contrary to experimental evidence derived from the combined analysis of Knight shift and susceptibility data, the calculated probability density at the nucleus for Fermi-surface electrons tends to increase rather than decrease as a function of decreasing density. This suggests that many-electron correlation effects play an essential role in determining the electronic properties of liquid cesium in the low-density limit where ρ1.3 g cm^-3 and the nearest-neighbor coordination number z6.