Hybrid potential of interparticle interaction and calculation of melting of lithium using the molecular dynamics method

A multiparticle potential of a new type (EAM-2) including the degree of crystallinity of atoms as a parameter has been proposed for metal systems. This potential is based on the potential of the embedded atom model (EAM). The degree of crystallinity of atoms is determined by the expansion of the radius-vectors of neighboring atoms over spherical functions and the calculation of the characteristic $q_6$. The potential EAM-2 describes well the properties of liquid, BCC, and FCC lithium at conventional and high pressures. The lines of equilibrium BCC-lithium–liquid and FCC-lithium–liquid were calculated at pressures up to $40$ GPa, and good agreement with the experiment including for the maximum on the melting curve was obtained. Tables of the pressure and temperature dependences of the density and energy of the models are given. The anomalous behavior of the density BCC and FCC lithium in the pressure interval of $25$–$30$ GPa (increase in the density during isobaric heating) is noted.