Measurements of charge transfer cross sections for Arq+ (q=6, 7, 8, 9 and 11) collisions with He and H2 targets at low energies

Abstract

The cross sections for single‐ and double‐electron transfer, neglecting the transfer ionization processes, have been measured for Arq+ (q=6, 7, 8, 9 and 11) with H2 and He at low energies ranging from 0.075 to 225 eV/amu, systematically. The single‐electron transfer cross sections were found to distribute between the predictions of the scaling law by Müller and Salzborn and the absorbing model by Olson and Salop above about 1 eV/amu and to converge to the Langevin cross section at the low energy end measured. For the same projectile ion, the single‐electron transfer cross sections for the H2 targets are about threefold as large as those for the He target and both energy dependencies are very similar. The double‐electron transfer cross sections are smaller than those for the single‐electron transfer and they are characterized by a minimum structure near 1 eV/amu for He targets. All cross sections for the single‐ and double‐electron transfer have a common signature increasing with decreasing collision energy at the low energy end measured. With analyses by simple models and the MCLZ calculation, the importance of an attractive induced‐dipole polarization potential in the highly charged ion collisions is discussed.