Inelastic processes in collisions of Na(3s,3p) with He at thermal energies

C. Y. Lin (1) , P. C. Stancil (2) , H.-P. Liebermann (3) , P. Funke (3) , R. J. Buenker (3)

1 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
2 Department of Physics and Astronomy and Center for Simulational Physics, University of Georgia
3 Fachbereich C-Mathematik und Naturwissenschaften

Inelastic collisions of sodium due to low-energy helium are investigated using the quantum-mechanical molecular-orbital coupled-channel method. The calculations adopt adiabatic potentials and nonadiabatic radial and rotational couplings obtained with the multireference single- and double-excitation configuration interaction approach. The potentials are fitted to long-range dispersion coefficients and adjusted with a model interaction in the van der Waals well region. Collisional cross sections for energies between 0.001eV and 10eV and rate coefficients as a function of temperature between 10K and 10000K are obtained for Na(3p-->3s) quenching and Na(3s-->3p) excitation. The results are relevant to modeling non-LTE effects in Na D absorption lines in extrasolar planets and brown dwarfs.

Domaines: Astrophysique [astro-ph]; Planète et Univers [physics]

C. Y. Lin, P. C. Stancil, H.-P. Liebermann, P. Funke, R. J. Buenker. Inelastic processes in collisions of Na(3s,3p) with He at thermal energies. Physical Review A, 2008, 78, pp.52706. ⟨10.1103/PhysRevA.78.052706⟩. ⟨hal-03796883⟩