Electron capture in slow collisions of O⁶⁺ ions with atomic hydrogen^⋆

¹ School of Physics, Beijing Institute of Technology, Beijing 100081, PR China
² Institute of Applied Physics and Computational Mathematics, Beijing 100088, PR China
e-mail: wu_yong@iapcm.ac.cn
³ HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100084, PR China
⁴ Macedonian Academy of Sciences and Arts, PO Box 428, 1000 Skopje, Macedonia

Received: 19 December 2018
Accepted: 2 March 2019

Abstract

Aims. Electron capture in collisions of highly charged O⁶⁺ ions with ground-state hydrogen atoms is a very important process in solar wind X-ray studies.

Methods. In the present study, the full quantum-mechanical molecular-orbital close-coupling method is employed to study electron capture reactions in collisions of O⁶⁺ ion with ground-state atomic hydrogen in the energy region from 10⁻⁴ keV u⁻¹ to 5 keV u⁻¹. The ab initio multi-reference single- and double-excitation configuration interaction (MRD-CI) method is used to calculate the potential and coupling data used in the QMOCC calculations.

Results. Total and state-selective cross sections for the dominant and subdominant reaction channels are calculated and compared with the available experimental and theoretical data. The branching ratios for Lithium-like O⁵⁺ excited ions are used to calculate the contribution of cascade radiative transitions from n = 5 levels to the population of 4l states. From the calculated cross sections, reaction rate coefficients are obtained for temperatures between 1000 and 1 × 10⁹ K and compared with other calculations.