Extended Finnis–Sinclair potential for bcc and fcc metals and alloys

Abstract

We propose an extended Finnis–Sinclair (FS) potential by extending the repulsive terminto a sextic polynomial for enhancing the repulsive interaction and adding a quartic termto describe the electronic density function. It turns out that for bcc metals the proposedpotential not only overcomes the ‘soft’ behaviour of the original FS potential,but also performs better than the modified FS one by Ackland et al, and thatfor fcc metals the proposed potential is able to reproduce the lattice constants,cohesive energies, elastic constant, vacancy formation energies, equations of state,pressure–volume relationships, melting points and melting heats. Moreover, for somefcc–bcc systems, e.g. the Ag–refractory metal systems, the lattice constants, cohesiveenergies and elastic constants of some alloys are reproduced by the proposedpotential and are quite compatible with those directly determined by ab initiocalculations.