A Molecular Dynamics Simulation of the Electric and Thermodynamic Properties in Molten (Nd1/3, Na or K)Cl Mixtures

Abstract

Abstract Molecular dynamics simulations have been carried out on molten (Nd1/3, K)Cl at 1065 and 1073 K and (Nd1/3, Na)Cl at 1124 K for various compositions. The calculated self-exchange velocity (v ), self-diffusion coefficient (D), electrical conductivity (k) and enthalpy of mixing ( ΔHmix) were compared with the corresponding experimental values. The calculated results revealed that v and D of potassium decrease with increasing anmount of neodymium, as expected from the experimental internal mobility (6). The decrease of bK, vK, and DK are attributed to the tranquilization effect by Nd3+ which strongly interacts with Cl- as well as Dy3+. On the contrary, bNd, VNd, and DNd increase with increasing concentration of Nd3+. This might be ascribed to the stronger association of Nd3+ with Cl- due to the enhanced charge asymmetry of the two cations neighboring Cl- . In addition, the sequences of the calculated v's, D's and k ’s for the various compositions were consistent with those of the known experimental results. The experimental enthalpy of mixing with its negative dependence on the cation size was qualitatively reproduced.