ABSTRACT
We continue the discussion of drift and diffusion of electrons in gases that have complex molecules. A theoretical framework has been established so that we can present data in a compressed manner, wherever possible. The chapter begins with an introduction to the pulse method of measuring the drift velocity, as the technique still needs to be employed to study a large number of molecules for which data are incomplete or for which there is a need to update the older data with respect to accuracy and range of E/N to be covered. Drift velocity is measured by the use of the following techniques1:
1. Electrical shutter method. The method was introduced by Bradbury and Nielsen and was applied to a number of gases. A variation of the method is the double shutter method, in which two closely spaced shutters are placed near the cathode and anode. The distance between them is the drift distance.
