Volume 572, December 2014
|Number of page(s)||7|
|Section||Atomic, molecular, and nuclear data|
|Published online||04 December 2014|
Inelastic silicon-hydrogen collision data for non-LTE applications in stellar atmospheres⋆
1 Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
2 Department of Theoretical Physics and Astronomy, Herzen University, 191186 St. Petersburg, Russia
Received: 30 July 2014
Accepted: 17 September 2014
Aims. Inelastic processes in low-energy Si + H and Si+ + H− collisions are treated for the states from the ground state up to the ionic state, in order to provide rate coefficients needed for non-LTE modeling of Si in cool stellar atmospheres.
Methods. Electronic molecular structure is determined using a recently proposed model approach based on an asymptotic method in combination with available ab initio potentials. Nonadiabatic nuclear dynamics are treated by means of a combination of multichannel formulas and the branching-probability-current method, based on the Landau-Zener model for nonadiabatic transition probabilities.
Results. Cross sections and rate coefficients for inelastic processes in Si + H and Si+ + H− collisions for all transitions between 26 low-lying states plus the ionic state are calculated. It is shown that the highest rate coefficient values correspond to the excitation, de-excitation, ion-pair formation, and mutual neutralization processes involving the Si(3p4p 3D), Si(3p3d 3F), Si(3p4p 1D), Si(3p3d 3P), Si(3p4p 1S), and the ionic Si+ + H− states. These processes are likely to be important in non-LTE modeling.
Key words: atomic data / line: formation / stars: abundances
Tables 2–11 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/572/A103
© ESO, 2014
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