INTERATOMIC INTERACTIONS FOR MO AND W BASED ON THE LOW-ORDER MOMENTS OF THE DENSITY-OF-STATES

A model of the energetics of bec transition metals based on the low-order moments of the electronic density of states is presented. The effects of the changes of the coarse shape of the density of states are included via a fourth moment term in a manner similar to other recently proposed models. The model is tested by the computation of point defect properties, phonon dispersions, structural energy differences, and surface properties. The results are compared to experiment, ab initio calculations, and other model interatomic potentials. The results indicate that the inclusion of the fourth moment term in the energy does not significantly improve the description of properties with structures close to that of the bulk bcc lattice. However, the fourth moment term substantially improves the description of large deviations from the bulk bcc lattice such as surfaces and alternative crystal structures.