Repulsive potentials derived from beam scattering of Rb+ and Cs+ ions by rare gas atoms

Integral cross sections of elastic scattering through effective LAB angles greater than 5×10−3 rad have been measured for collisions of Rb+ and Cs+ ions in the LAB energy range 500–4000 eV with room temperature rare gas atoms (He through Xe). Repulsive potentials in the range 0.5–10 eV derived from the results for the ion–atom pairs can be all expressed by exponential formulas. The potentials for Rb+–Ar, –Kr, and –Xe are in excellent agreement with the results derived from the mobility experiments by Gatland et al., but agreement between the two experiments for Cs+–Ar, –Kr, and –Xe are poor. The potential values calculated by Ishikawa et al. on the basis of the Gordon–Kim electron gas model are generally 20%–25% lower than the results of the present work.