Atomic data on inelastic processes in low-energy beryllium-hydrogen collisions ^⋆

¹ Max-Planck Institute for Astrophysics, Postfach 1371, 85741 Garching, Germany
e-mail: andrey.k.belyaev@gmail.com
² Department of Theoretical Physics and Astronomy, Herzen University, 191186 St. Petersburg, Russia

Received: 7 April 2016
Accepted: 4 June 2016

Abstract

Aims. Inelastic processes in low-energy Be + H and Be⁺ + H⁻ collisions are treated for the states from the ground and up to the ionic state with the aim to provide rate coefficients needed for non-local thermodynamic equilibrium (non-LTE) modeling of beryllium spectra in cool stellar atmospheres.

Methods. The electronic molecular structure is determined by using a recently proposed model quantum approach that is based on an asymptotic method. Nonadiabatic nuclear dynamics is treated by means of multichannel formulas, based on the Landau-Zener model for nonadiabatic transition probabilities.

Results. The cross sections and the rate coefficients for inelastic processes in Be + H and Be⁺ + H⁻ collisions are calculated for all transitions between 13 low-lying covalent states plus the ionic state. It is shown that the highest rate coefficient values correspond to the mutual neutralization processes with the final states Be(2s3s ¹S), Be(2s3p ^1,3P), Be(2s3d ³D). These processes, as well as some of the excitation, de-excitation and ion-pair formation processes, are likely to be important for non-LTE modeling.