Charge transfer of keV O⁺ ions with atomic oxygen

B. G. Lindsay, D. R. Sieglaff, K. A. Smith, and R. F. Stebbings

J. Geophys. Res. 106, 8197-8203 (2001)

We report absolute differential cross sections for charge transfer scattering of 0.5-5 keV O⁺(⁴S) ground state and O⁺(²D, ²P) metastable ions by atomic oxygen at angles between 0.04° and 3° in the laboratory frame. Absolute total charge transfer cross sections, derived from these measurements, are compared with previously published data. The measurements were made using a flowing gas target, which consisted of a mixture of atomic and molecular oxygen produced by passing O₂ through a microwave discharge. The atomic oxygen cross sections were obtained by appropriate subtraction of the signal due to molecular oxygen from that due to the mixture of O and O₂. These data are relevant to model calculations of energetic O⁺ precipitation into the upper atmosphere and to the diffusion of low energy O⁺ ions in the ionosphere.