Open AccessThe excitation of molecular hydrogen by atomic hydrogen in astrophysical media
Author(s) -
Wrathmall S. A.,
Gusdorf A.,
Flower D. R.
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2007.12420.x
Subject(s) - physics , rotational–vibrational spectroscopy , atomic physics , excitation , hydrogen , relaxation (psychology) , harmonic oscillator , inelastic scattering , collisional excitation , reaction rate , scattering , excited state , ion , ionization , quantum mechanics , psychology , social psychology , biochemistry , chemistry , catalysis
We report calculations of rate coefficients for the rovibrational excitation of H 2 and HD by H. The calculations relate explicitly to non‐reactive scattering, excluding the proton‐exchange channels. For vibrationally inelastic transitions, the new rate coefficients at T ≈ 1000 K are larger than the results of earlier calculations in which the vibrational motion was treated approximately, by means of a simple harmonic oscillator model. As a result, much better agreement is obtained with the empirical estimates by Allers et al. of the rate coefficients for vibrational relaxation of the levels ( v , j ) = (1, 3) and (2, 3) of H 2 . However, the effects of the new data on the results of illustrative astrophysical models – of a C‐type shock wave and of the gravitational collapse of a condensation of the primordial gas – are less pronounced than the changes to the rate coefficients for vibrationally inelastic transitions might suggest; we explain why this is the case.