ELECTRON IMPACT DISSOCIATION X (1)Sigma(+)(g) -> b (3)Sigma(+)(u) AND EXCITATIONS X (1)Sigma(+)(g) -> a (3)Sigma(+)(g) AND X (1)Sigma(+)(g) -> B (1)Sigma(+)(u) OF MOLECULAR HYDROGEN IN NONTHERMAL ASTROPHYSICAL PLASMAS

Abstract

We investigate the electronic transitions X (1)Sigma(+)(g) -> b (3)Sigma(+)(u), X (1)Sigma(+)(g) -> a (3)Sigma(+)(g), and X (1)Sigma(+)(g). B (1)Sigma(+)(u) of molecular hydrogen by studying electron impacts in astrophysical Lorentzian plasmas. Useful fitting formulae for the X (1)Sigma(+)(g) -> b (3)Sigma(+)(u), X (1)Sigma(+)(g) -> a (3)Sigma(+) (g), and X (1)Sigma(+)(g) -> B (1)Sigma(+)(u) excitation cross sections are employed in order to obtain the electronic excitation rate coefficients of H2 as functions of the spectral index and temperature. In low-temperature regions, it is found that the excitation rate coefficients R-b(Sigma)u(3)+, R-a(Sigma)g(3)+, and R-B(Sigma)u(1)+ of H2 in non-Maxwellian plasmas are smaller than those in Maxwellian plasmas. However, in high-temperature regions, the excitation rate coefficients of H2 in non-Maxwellian plasmas are greater than those in Maxwellian plasmas. It is also shown that the X (1)Sigma(+)(g) -> b (3)Sigma(+)(u) excitation rate coefficient is the main contributor in low-temperature regions. In contrast, it is found that the X (1)Sigma(+)(g) -> B (1)Sigma(+)(u) electronic excitation is dominant in high-temperature regions.