Non-radiative inelastic processes in lithium-helium ion-atom collisions

Abstract

Aims. The aims are to estimate efficiencies of non-radiative inelastic processes in lithium-helium ion-atom collisions and to compare them to those for radiative processes. Methods. Non-radiative inelastic cross-sections and rate coefficients for different lithium-helium ion-atom collisions are estimated by means of the recently proposed branching probability current method, which is based on the accurate ab initio adiabatic BornOppenheimer potentials that have been recently calculated for the low-lying 1,3 Σ + and 1,3 Π states of the LiHe + ion. Results. It is shown that at low temperatures the radiative depopulation in Li + + He and Li + He + collisions dominates over the non-radiative processes, while in Li + + He(2s 3 S) collisions the non-radiative processes dominate over the radiative association at temperatures above 3000 K, which can be expected to have some influence on depopulations of metastable He in high temperature astrophysical environments.

Theoretical study of electronic excitation, ion-pair formation, and mutual neutralization in cesium-hydrogen collisions

“…In the present work, the LZ parameters are calculated from the accurate ab initio electronic-structure calculations [27] and thus yield reliable cross sections. The branching-probability-current method has been applied to aluminium-hydrogen [34,38] and to lithiumhelium ion-atom [39] inelastic collisions.…”

Division B Commission 14 Working Group: Collision Processes

“…New references regarding charge transfer involving He and He + include: He + + He (Kusakabe et al 2012), Li + He (Belyaev et al 2014), Si + He + (Satta et al 2013), C 4+ + He collisions (Yan et al 2013), O 8+ + He collisions , Ne 10+ + He, Ne (Liu et al 2014d). An overview of charge transfer and ionisation for heavy manyelectron ions colliding with neutral atoms has been given in (Tolstikhina & Shevelko 2013) and W + , W 2+ + He (Tolstikhina et al 2012).…”