Evaluation of Vibration Spectrum and Heat Capacities of Tungsten and Molybdenum by de Launay's Electron Gas Model

Abstract

De Launay's model of electron‐lattice interaction has been applied to the evaluation of the vibration spectrum of two‐body‐centred cubic metals viz. tungsten and molybdenum. Following KELLERMANN the reciprocal phase space is divided into 10 × 10 × 10 cells. However, the secular determinant is solved only for 47 points of the first Brillouin Zone (including the origin). A correct enumeration, considering the proper statistical weights, yields 3,000 frequencies ‐ a point missed by the earlier workers. The calculated specific heats are in very good agreement with the experimental values. In the case of tungsten the results have been compared with those of FINE who ignored the effect of the electrons in the lattice vibrations. It is found that de Launay's model gives a better agreement with observed data than Fine's at all temperatures. Copyright © 1961 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim