External Field Dependence of Transport Properties. I. Thermal Conduction in a Fluid of Rough Spheres

Abstract

A theory of thermal conduction is developed for a gas composed of rotating molecules which is subject to an external electric or magnetic field. This theory of the Senftleben–Beenakker effect is based upon a kinetic equation of the Boltzmann variety and is sufficiently general to include virtually all cases of interest. Application has been made to the rough‐sphere model of collisional events and numerical values of the three independent elements of the thermal conductivity tensor obtained. Although the model is rather unrealistic, comparisons with experiment have been made whenever possible. Agreement as to order of magnitude and functional dependence upon field strength is satisfactory but by no means perfect. In these calculations it has been assumed that the molecules either were diamagnetic, e.g., N₂, or paramagnetic doublets, e.g., NO. The calculations were extended to high density by invoking a modification of the Enksog theory for a dense gas of smooth spheres. The flux of internal angular momentum caused by a gradient of temperature has been computed.