Gupta potentials for five HCP rare earth metals.

Empirical Gupta-type potentials based on the second-moment approximation of tight-binding model have been developed for five hexagonal-closed-packed (hcp) rare earth metals: Er, Dy, Gd, Tb, Lu. The potentials can reproduce experimental cohesive energies, lattice constants and elastic constants of Er, Dy, Gd, Tb and Lu. The calculated bulk moduli, shear moduli, sound velocities and Debye temperatures are in reasonable agreement with the measured values. Vacancy formation energies and surface energies of these metals are also calculated and compared with previous theoretical results. Our potentials are able to simulate the phonon dispersions of Tb, Er, Dy, Gd, and Lu solids and reproduce Tb’s experimental data in detail. The present Gupta potentials would be useful for future simulations of elementary metals of Er, Dy, Gd, Tb, Lu and their alloys. [ABSTRACT FROM AUTHOR]