The static structure factor of cesium over the whole liquid range up to the critical point

The paper presents the first neutron scattering investigation of the static structure factor S(Q) of expanded liquid cesium from the melting point up to its critical point at conditions near the liquid-vapour coexistence curve (critical data of cesium: Tc = 1924 K, pc = 92.5 bar, Dc = 0.379g/cm3). The characteristic changes of the microscopic structure - such as the distance and number of nearest neighbours - are derived as a function of density. The reported results give useful information about the density dependent changes in the electronic structure in course of the transition from a metallic to a nonmetallic state which occurs in the expanded metal. In particular, the results provide direct experimental evidence for the limitation of the nearly-free-electron (NFE) model in describing the electrical transport properties of low density fluid cesium. (orig.)