Non-radiative inelastic processes in lithium-helium ion-atom collisions
1 Department of Theoretical Physics and Astronomy, Herzen University, St. Petersburg 191186, Russia and Max-Planck Institute for Astrophysics, Postfach 1371, 85741 Garching, Germany
2 Charles University in Prague, Faculty of Mathematics and Physics, Department of Chemical Physics and Optics, Ke Karlovu 3, 12116 Prague 2, Czech Republic
3 Max-Planck Institute for Astrophysics, Postfach 1371, 85741 Garching, Germany
Received: 5 February 2014
Accepted: 12 March 2014
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 Born-Oppenheimer potentials that have been recently calculated for the low-lying 1,3Σ+ and 1,3Π 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 3S) 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.
Key words: atomic data / molecular data / scattering
© ESO, 2014