VARIATION OF REDUCED MOBILITIES OF IONS IN GASES UNDER 12-4-POTENTIALS

In order to understand the variety of ion mobilities in gases under co mmon ion-neutral interaction potentials, systematic calculations have been performed assuming the 12-4 inverse power potentials with several force constants. It is found that the momentum-transfer collision fre quencies calculated from the potentials as functions of relative speed can definitively explain the feature of mobilities. As a result, ion mobilities with and without a hump, with positive and negative derivat ives referred to reduced electric field and to gas temperature have be en clearly understood in relation with the potential shapes.