AN EMBEDDED-ATOM METHOD POTENTIAL FOR THE HCP METAL ZR5

The embedded atom method is extended to the h.c.p. metal Zr. The non-ideal c:a ratio and the elastic responses, including contributions-from internal degrees of freedom, are incorporated in the fitting procedure; Simple functional forms are assumed for the pair interaction, atomic electron density and embedding function. The functions are parametrized by fitting to experimental data: cohesive energy, equilibrium lattice constants, single crystal elastic constants and vacancy formation energy. An equation of state of the form proposed by Rose, Smith, Guinea and Ferrante is used to reproduce the pressure dependence of the cohesive energy, taking into account the anisotropic elastic response of the crystal. Dimer data and a high energy sputtering potential are also reproduced to extend the range of validity of the potential into regions of very high and low electron density. Good agreement is obtained between the experimental and calculated properties: The potential is applied to the calculation of stacking fault and self-interstitial formation energies.