Application of the embedded atom model to liquid metals: Liquid sodium

Abstract

The procedure for the calculation of the embedded atom model (EAM) potential for liquid metal, which involves the use of diffraction data on the structure of material in the vicinity of the melting point, is applied to lithium. In fitting the parameters of EAM potential, use is made of data on the structure of lithium at 463, 523, and 868 K, as well as on the thermodynamic properties of lithium at temperatures up to 3400 K. The use of the method of molecular dynamics (MD) and of the EAM potential enables one to obtain good agreement with experiment as regards the structure, density, and potential energy of liquid metal at temperatures up to 3000 K, as well as along the shock adiabat up to pressures of ∼260 GPa. The predicted value of bulk modulus at 463 K is close to the actual value. The self-diffusion coefficients under isobaric heating increase with temperature by the power law with exponent of 1.7182. The obtained potential is inadequate for describing crystalline lithium. The predicted melting temperature of lithium with EAM potential is 428 ± 2 K and is close to real temperature.