Molecular-dynamics study of liquid NaPb, KPb, RbPb, and CsPb alloys

Abstract

A molecular-dynamics study on equiatomic NaPb, KPb, RbPb, and CsPb liquid alloys has been carried out to supplement earlier neutron-diffraction measurements. The alkali-metal atoms are assumed to be monovalent, positively charged ions while the Pb atoms are arranged in regular tetrahedra, (${\mathrm{Pb}}_{4}$${)}^{4\mathrm{\ensuremath{-}}}$, so-called Zintl ions. A simplified version of the Tosi-Fumi potential has been used to represent the interatomic forces, except for the Pb-Pb interactions within a (${\mathrm{Pb}}_{4}$${)}^{4\mathrm{\ensuremath{-}}}$ ion, which are approximated by a harmonic potential. The structure factors calculated from this molecular-ionic model prove to be in excellent agreement with the measured ones.