Lattice statics of close packed hexagonal metals: vacancy in magnesium

The authors have formulated the lattice statics method for hexagonal close packed metals and applied it to a vacancy in magnesium. Both near neighbour and asymptotic displacements have been calculated and compared. The results indicate that, as in cubic metals the elastic limit is achieved far from the defect and that the asymptotic displacements are very anisotropic. The calculated relaxation energy indicates that in Mg, as is the case in Al, the relaxation contribution to the vacancy formation energy is small. To describe the interatomic interactions the authors have used two different methods: force constants deduced from the neutron scattering data and interatomic potentials calculated from Shaw's nonlocal model potential.