Rate coefficients for electron impact excitation of the a ³Π state of CO

Abstract

Integral cross sections for electron impact excitation of the first six vibrational levels of the valence a 3Π state of the carbon monoxide molecule have been determined from our recent measurements of the differential cross sections, in the energy region from threshold to 10 eV. These results are used to calculate rate coefficients for electron impact excitation of the a 3Π state of CO. Calculations are performed for Maxwellian electron energy distribution functions (EEDFs) in the mean electron energy region from 0 to 17 eV. By using extended Monte Carlo simulations, the EEDFs and rate coefficients are determined for the non-equilibrium conditions, in the presence of a homogeneous external electric field. These calculations are performed for typical, moderate values of the electric field over gas number density ratios, E/N, from 1 to 1000 Td. A small difference between Maxwellian and non-equilibrium rate coefficients was found due to a specific shape of the electron energy distribution functions under the considered conditions. Comparison is also made with the results obtained for EEDFs generated by numerically solving the Boltzmann equation based on a two term Legendre expansion of the velocity distribution function, calculated with the software BOLSIG+ v1.1. © 2012 Elsevier B.V. All rights reserved.