Inelastic aluminium-hydrogen collision data for non-LTE applications in stellar atmospheres

¹ Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
e-mail: belyaev@herzen.spb.ru
² Max Planck Institut für Astrophysik, 85741 Garching bei München, Germany

Received: 29 July 2013
Accepted: 21 October 2013

Abstract

Aims. Rate coefficients for inelastic Al + H and Al⁺ + H⁻ collisions are calculated for all transitions between the seven low-lying levels up to and including the ionic state, namely Al(3p,4s,3d,4p,5s,nd)+H(1s) and Al⁺ + H⁻. The data are needed for non-LTE applications in stellar atmospheres and are presented for a temperature range of 1000–10 000 K.

Methods. The calculations were obtained by means of the recently proposed model approach based on the asymptotic method for electronic molecular structure determination and on the branching probability current method for the nonadiabatic nuclear dynamics.

Results. It is shown that the processes with the highest rates are the excitation and de-excitation ones between the Al(3d), Al(4p) and Al(4s) states in collisions with H, as well as the ion-pair formation and the mutual neutralization processes between these states and the ionic state.