A Method for the Parametrization of the Pairwise Interatomic Potential

Abstract

Drawbacks of some methods known from the literature for determining four parameters of the Mie–Lennard-Jones pairwise interatomic potential as applied to crystals are pointed out. A new method for parametrization of the potential by thermoelastic properties of the crystal is proposed. The method determines the parameters by the best agreement of the calculated values with experimental data such as (1) the sublimation energy of the crystal at the zero values of the temperature (T = 0 K) and pressure (P = 0), (2) the thermal expansion coefficient and the isothermal modulus of elasticity measured at P = 0 and T = 300 K, and (3) the dependence of the isotherm curve T = 300 K of the equation of state on the volume P(300 K, V). The method was verified for iron and gold and showed good results. Further, the proposed method was applied to determine the parameters of the interatomic potential for refractory metals, viz., Nb, Ta, Mo, and W. The results obtained also allowed for more accurate determination of the sublimation energy, the Debye temperature, and the surface energy of the above metals.