Mobilities in Some Free Electron Gases

Abstract

Mobility coefficients for free electrons and mobilities of positive ions are reported for hydrogen, deuterium, and some mixtures of hydrogen and nitrogen, and of hydrogen and helium, for field strengths between 1 and 2 volts per cm per mm of mercury gas pressure. The relation between free electron drift velocity and field strength is found to be parabolic in this range for all these gases. Discussion of these observations shows that they can be explained qualitatively if electrons excite rotations of the hydrogen molecules by collision, and the cross sections for this process are estimated. A mathematical appendix states the theoretical results required in the discussion and derives those details not previously obtained.