Mobilities and interaction potentials for Cs+–Ar, Cs+–Kr, and Cs+–Xe

Abstract

The mobilities of Cs+ ions in Ar, Kr, and Xe gases at 300 °K have been measured in a drift tube mass spectrometer for a wide range of values of the energy parameter E/N (the ratio of the electric field strength to the gas number density). Ion neutral interaction potentials have also been derived for each case (Cs+–Ar, Cs+–Kr, and Cs+–Xe). A kinetic theory appropriate to the nonthermalized ion motion is used to derive the mobilities from the potentials, and an iterative technique is used to modify the potentials to fit the experimental data. Various tests of the accuracy and uniqueness of the method indicate that this determination of the potentials gives errors in the potential parameters, e.g., well depth, well position, etc., which are less than about 10%.