Transport in some Alkalis

Abstract

We have calculated the constant pressure and constant volume ideal electrical resistivities of the alkali metals Na, K, and Rb. In addition we have also calculated the ideal thermal resistivities of K and Rb. Information about the phonons is taken from a Born – von Kármán force constant analysis of dispersion curves at a particular temperature, obtained from inelastic neutron scattering. The shifts in phonon frequencies with volume are accounted for, approximately, by a uniform scaling using the known Grunëisen parameter and the measured volume changes. The electron–ion interaction is treated in pseudopotential theory and the one parameter Ashcroft form is used throughout. The calculations are reformulated in terms of two "transport frequency distributions", [Formula: see text] and [Formula: see text], which allow volume and temperature effects to be treated simply. The results compare very favorably with experiment over a wide temperature range.