First-principles molecular-dynamics simulation of expanded liquid rubidium

The structural and electronic properties of expanded liquid rubidium are studied at 350 K, near the triple point, and 1400 K by means of a first-principles molecular-dynamics (MD) simulation, where the Kohn-Sham energy functional is minimized for each ionic configuration of the MD step using the preconditioned conjugate-gradient method. The results for the static structure at both temperatures and the diffusion coefficient near the triple point are in good agreement with experiments. While near the triple point the electron density {ρ}(r) spreads over whole space, at high temperature {ρ}(r) tends to localize due to a large spatial fluctuation of atomic density. The electron-ion correlation function is calculated using {ρ}(r) and its temperature dependence is discussed.