Calculation Of Phonon Dispersion Frequencies For Bcc Tantalum Using Resonance Pseudopotential Model

Abstract

The phonon dispersion frequencies are calculated from first principles for bcc Tantalum using a resonance pseudopotential model. It was also possible, using this scheme, to account for the anomalous feature of the Ta dispersion curve observed experimentally in the (ε,o,o,) direction where the frequencies of the transverse branch are higher than the frequencies of the longitudinal branch. The frequencies obtained were also used to calculate the phonon density of states by the linear – analytic tetrahedral method of zone integration. The results of these calculations are qualitatively in good agreement with experimental data, and provide further support to the interpretation of the anomalous behaviour in the (ε,o,o,) direction as arising from s-d hybridization.

Keywords: Phonon dispersion, phonon frequency, resonance, pseudopotential model, Phonon density of states.

Nigerian Journal of Physics Vol. 19 (1) 2007: pp. 17-22