Variations in electron transport in argon with temperature near the Ramsauer-Townsend minimum

A previously developed three-term expansion method has been extended to study the electron swarm in argon in the energy range of the Ramsauer-Townsend minimum. The swarm parameters of electrons have been computed at temperatures of 89.6, 293 and 1000K in the range 1*10 -21 <or=E/N (V cm 2 )<or=1*10 -17 . In particular, the dependence of the drift velocity on gas temperature in the vicinity of the minimum is discussed in detail, and it is shown that a 'crossing curve' property appears. Also the validity of the conventional two-term approximation is confirmed by direct comparison with the lth-order distribution function (l=0, 1, 2) in the region of the minimum.