Interatomic potentials for rare-earth metals

We present semi-empirical interatomic potentials for the rare-earth metals (Sc, Y, La and lanthanides) and their compounds within the framework of the hybridized nearly-free-electron-tight-binding-bond (NFE-TBB) model. Potent ial parameters are adjusted to reproduce the experimental data for interato mic spacings and elastic constants. The derived potentials are found to pro vide good agreement with the experimental data for the face-centred cubic, hexagonal close-packed and double-hexagonal close-packed elemental rare-ear th metals. We have also made a comparison between the bond-angle-dependent tight-binding-d-bond model and the bond-angle-independent model. Within the present model, we have found that the bondings in the rare-earth metals de pend on the bond angles, and the dependence is weaker compared with those i n the transition metals.