A LATTICE INVERSION METHOD TO CONSTRUCT THE ALLOY PAIR POTENTIAL FOR THE EMBEDDED-ATOM METHOD

The lattice inversion method is used to construct the pair potential between a pair of unlike atoms for Cu-Au and Cu-Pd intermetallic compounds within the framework of Johnson's analytical model of the embedded-atom method. Compared with previous treatises, the alloy potential obtained by the present method is based on the LI(2) superstructures Cu3Au and Cu3Pd as references so that the usual assumption that the pair potential between distinct atoms is a function of monatomic pair potentials is cancelled. The alloy potentials from inversion fall in with those from the average schemes of Foiles et al and Johnson in the short range but show deviation in the long range. The present method is used to solve the considerable disagreements of Johnson's calculations for the dilute-limit heats of solution and the phase stabilities of the intermetallic compounds of palladium with noble metals. While the overall degree of agreement is substantially improved, it is not good in some cases, nor is the phonon spectrum of gold.