The effect of electron attachment on the ion mobility curves in the Zeleny air blast method of ion mobility measurement

In a recent paper Professor John Zeleny published curves obtained for ion mobilities at different ion ages in relatively pure N₂ using his classical air blast method. Two features are of especial interest; one the apparent gradual displacement of the negative ion peak to lower mobilities as the ion age increases and the other a marked asymmetry of the electron peak on the low mobility side. This Zeleny interprets as an unresolved negative ion mobility of value about 100 cm./sec. per volt/cm. Such a mobility can only be explained by a carrier that is ion part of its life and electron part of its life, the electronic and ionic phases alternating frequently. The writers indicate that the latter interpretation cannot be correct on the basis of the energies and probabilities involved in electron attachment. Analysis shows that the whole series of the observed phenomena in N₂ by this method are successfully accounted for on the proper application of the simplified theory of electron attachment to the air blast method. Since the attachment phenomena have to date not been applied to this type of mobility study it was felt of importance to present this analysis in order to guide future investigations by this method.