Structure factor and pseudopotential of liquid metallic lithium determined from the nucleus-electron model.

Abstract

By treating a liquid metal as a mixture consisting of nuclei and electrons, we have derived a set of integral equations for calculating radial distribution functions (RDF's) from the atomic number as the only input data; the internal atomic structure of an ion in a liquid metal is obtained self-consistently with the liquid structure at the same time. Here, we apply this formulation to liquid metallic lithium using further two approximations: (1) the local-field correction factor for electrons in a liquid metal is approximated by that of the jellium model, and (2) the ion-ion bridge function is replaced by that of the Percus-Yevick equation for a hard-sphere fluid. We calculate the structure factors at 470 and 595 K, which show excellent agreement with the experimental ones. Simultaneously we obtain the electron-ion RDF, which gives the charge distribution \ensuremath{\rho}(r) of a neutral pseudo- atom taking account of nonlinear screening. We extract a nonlinear pseudopotential ${w}_{b}^{\mathrm{nl}(\mathrm{r}}$) from the density \ensuremath{\rho}(r); this yields an interatomic interaction ${v}^{\mathrm{eff}(\mathrm{r}}$) giving the ion-ion RDF. Thus we determine the ion-ion and electron-ion RDF's, the charge distribution \ensuremath{\rho}(r) of a pseudoatom, the pseudopotential ${w}_{b}^{\mathrm{nl}(\mathrm{r}}$), and the pair interaction ${v}^{\mathrm{eff}(\mathrm{r}}$) in a self-consistent manner; they are also regarded as consistent with experiment.