Modified Angular Force Model in the Studies of Lattice Dynamics of B C C Metals: an Application to Sodium

Abstract

De Launay type angular force model has been applied to sodium to study the dispersion relations in the three symmetry directions. Electron-ion interaction has also been taken into account. The theoretical results are compared with the experimental ones obtained from inelastic neutron scattering and an excellent agreement has been obtained. The Cauchy discrepancy is attributed to the presence of both types of non-central interactions.