Electron-Ion Correlation in Liquid Metals from First Principles: Liquid Mg and Liquid Bi

We present a theoretical determination of electron-ion pair correlation functions $g_{\mathrm{ie}}$ in liquid Mg and liquid Bi, two systems with widely different electronic and cohesive properties. Our calculations are based on first-principles molecular-dynamics simulations, which provide an accurate and mutually consistent description of the atomic and electronic structures of these systems. Our results show that $g_{\mathrm{ie}}$ exhibits substantially different features in Mg and Bi liquids. For liquid Mg, $g_{\mathrm{ie}}$ clearly reflects the delocalization of the valence atomic charge related to metallic bond formation. In the case of Bi, instead, the spherical average implicit in $g_{\mathrm{ie}}$ does not allow it to reveal the existence of transient directional bonds which are an important feature of the charge density in this liquid.