Charge-changing Collisions of Stored, Multiply-charged Ions

Abstract

Abstract The results of measurements of rate coefficients for electron transfer from several target gases to multiply-charged ions are summarized and discussed. These measurements were carried out primarily in Penning ion traps. The stored ions were produced at low energy by several methods, including electron impact multi-ionization of atoms and molecules, recoil ions from impact of fast, stripped, heavy ions with target gas atoms, and inner shell photoionization of atoms using synchrotron radiation. The measurements typically do not exhibit any simple variation of the rate coefficients with ion charge state at these low energies, consistent with the expected mechanism of electron transfer at avoided crossings of the equipotential surfaces of the quasi-molecule formed during the collision. The magnitudes of the rate coefficients, and their trends with charge, are compared for different ions interacting with the same target, and with calculations of the rates using Langevin theory, which predicts a linear...