Electron impact excitation cross sections and energy degradation in CO

Abstract

We determine a comprehensive set of electron impact cross sections for carbon monoxide mainly on the basis of recently accumulated data on electron impact spectra, the Born approximation at high energies, and simple rules developed earlier to take into account low‐energy effects. The calculation of the complete energy degradation of electrons incident on CO is carried out with these input cross sections, and the efficiencies associated with possible loss channels are presented.

Monte Carlo model of electron transport for the calculation of Mars dayglow emissions

“…These newly formed electrons are transported in the thermosphere where they lose their kinetic energy in elastic, inelastic, and ionization collisions with the ambient atmospheric gas: where E and E′ (< E ) are the kinetic energies of the primary electron before and after a collision; X = CO 2 , CO, O, or N 2 ; X * and X + are atmospheric species in excited and ionized states, respectively; and E s is the energy of the secondary electron formed in the ionizing collision. We consider the following neutral and ionized excited states for the main atmospheric species: (1) excitation and dissociative excitation of CO 2 * = CO 2 ( v (010), v (100), v (001), electronic states at 8.6, 9.3, 11.1, 12.4, and 13.6 eV [see, e.g., Sawada et al , 1972a]; (2) direct ionization of CO 2 → CO 2 + ( X 2 Π, A 2 Π, B 2 Σ, C 2 Σ); (3) dissociative ionization of CO 2 → CO + + O, O + + CO, C + + O 2 ; (4) excitation of CO* = CO( a 3 Π, A 1 Π, electronic state at 13.5 eV [see, e.g., Sawada et al , 1972b]; (5) direct ionization of CO → CO + ( X 2 Σ, A 2 Π, B 2 Σ); (6) dissociative ionization of CO → C + + O, O + + C; (7) excitation of O* = O( 1 D − 1.96 eV, 1 S − 4.17eV, 3s 5 S 0 − 9.29 eV, 3s 3 S 0 − 9.53 eV, 3p 5 P 0 − 10.76 eV, 3p 3 P 0 − 10.97 eV, 3d 3 D 0 −12.07 eV, 3s 3 ' D 0 − 12.54 eV); (8) direct ionization of O → O + ( 4 S , 2 D , 2 P ); (9) direct ionization of N 2 → N 2 + ; (10) excitation and dissociative excitation of N 2 * ; and (11) dissociative ionization of N 2 → N + + N.…”

“…Cross sections for direct and dissociative ionization of CO 2 were adopted from the compilation by Itikawa [2002]. All cross sections for CO (excitation and ionization) were approximated by semiempirical formulas [ Sawada et al , 1972b]. Cross sections for all processes of electron impact on O and N 2 were taken from Green and Stolarski [1972], Jackman et al [1977], and the recent compilation by Itikawa [2006].…”

“…CO 2 + (X 2 P, A 2 P, B 2 S, C 2 S); (3) dissociative ionization of CO 2 ! CO + + O, O + + CO, C + + O 2 ; (4) excitation of CO* = CO(a 3 P, A 1 P, electronic state at 13.5 eV [see, e.g., Sawada et al, 1972b]; (5) direct ionization of CO ! CO + (X 2 S, A 2 P, B 2 S); (6) dissociative ionization of CO !…”

Measurement of absolute CO number densities in CH3F/O2plasmas by optical emission self-actinometry

“…Electron-impact excitation cross sections have been reported for reactions (1) and 7 [6]. The cross sections for reaction (1) is an estimate [6]. The values for reaction (7) have been reported to be valid, through a fortuitous cancelling of two factor of ∼10 errors [7].…”

“…Electron-impact excitation cross sections have been reported for reactions (1) and 7 [6]. The cross sections for reaction (1) is an estimate [6].…”