Electron Mobility in Liquid Argon

Abstract

Experiments of Williams (1957) showed that the drift velocity of electrons in liquid argon to which an electric field F is applied is essentially independent of F. If the electrons remain free then their motion can be described by kinetic theory, from which it appears that electron mobility is proportional to F-I and drift velocity to Fli. This is the dependence reported by Malkin and Schultz (1951), but it is evident that the recent, more exhaustive work of Williams (1957) is correct on this point and therefore that kinetic theory is not applicable to the problem. This theory could in principle be extended to explain a fieldindependent velocity, by supposing a special dependence upon electron energy of the scattering cross section for the collision of electrons with argon atoms, but this is very artificial and unnecessary in view of the alternative explanation suggested here; in any case it leaves further serious objections, which will also be discussed briefly.