Unified line profiles for hydrogen perturbed by collisions with protons: satellites and asymmetries

Abstract

We present new calculations of unified line profiles for hydrogen perturbed by collisions with protons. We report on new calculations of the potential energies and dipole moments which allow the evaluation of profiles for the lines of the Lyman series up to Lyman δ and the Balmer series up to Balmer 10. Unified calculations only existed for the lines Lyman α to Lyman γ and Balmer α including the H + 2 quasimolecule. These data are available as online material accompanying this paper and should be included in atmosphere models, in place of the Stark effect of protons, since the quasi-molecular contributions cause not only satellites, but large asymmetries that are unaccounted for in models that assume Stark broadening of electrons and protons are equal.

Semiclassical Treatment of High-Lying Electronic States of H2+

“…The results presented included states with dissociation limits up to H­( n ≤ 12) plus a proton, with internuclear separations R up to 250 a 0 . Pelisoli, Santos, and Kepler , performed calculations for internuclear separations up to 300 a 0 and dissociation limits with principal quantum numbers n ≤ 10 to study spectral line broadening of hydrogen in the atmospheres of white dwarf stars and laboratory plasmas; there has been discussion in the literature regarding the lack of state-resolved data for H 2 + . , In this paper, we include quantum calculations for higher excited electronic states that have not yet been calculated.…”

“…To our knowledge, the highest energy calculations were carried out by Rost and Briggs , and Pelisoli, Santos, and Kepler. , Rost and Briggs , elucidated the relationship between states of H 2 + and doubly excited states of atoms, focusing, in particular, on the saddle of the potential experienced by the electron. The results presented included states with dissociation limits up to H­( n ≤ 12) plus a proton, with internuclear separations R up to 250 a 0 .…”

State-resolved Photodissociation and Radiative Association Data for the Molecular Hydrogen Ion

“…State-resolved and summed photon-H 2 + data have been utilized in a range of models of the early universe's chemistry (Galli & Palla 1998;Stancil et al 1998;Lepp et al 2002;Hirata & Padmanabhan 2006;Coppola et al 2011), gas clouds chemistry (Ferland et al 2013;Lykins et al 2015;Coppola et al 2016;Sugimura et al 2016), solar atmospheres (Stancil 1994b;Mihajlov et al 2007), and the opacity of primordial matter (Mayer & Duschl 2005). In addition, H-H + collision-induced absorption effects (or quasi-molecular transitions) have been investigated to model Lyman satellites in the context of DA white dwarf atmospheres, old horizontal-branch stars of spectral type A, and λ Bootis stars (Allard et al 1998(Allard et al , 2000(Allard et al , 2009Santos & Kepler 2012;Pelisoli et al 2015).…”