Electron collisions with CO: Elastic and vibrational excitation cross sections

Absolute differential elastic and vibrational excitation cross sections up to v = 11 were measured for CO in scattering angle ranges extending to 180 degrees at energies between 0.2 and 5 eV ( and an elastic measurement at 10 eV). The lowest angles were 0 degrees for inelastic scattering and between 5 degrees and 20 degrees for elastic scattering, depending on energy. Integral cross sections were derived by integrating under the angular distributions and compared with previous beam and swarm measurements. The sum of the integral cross sections agrees very well with the available transmission measurements of the grand total cross section, thus validating the present measurements. The present elastic differential and integral cross sections are in excellent agreement with the best available measurement [Gibson et al., J. Phys. B 29, 3197 ( 1996)], but the v = 1 inelastic cross section is about 25% higher. This could have consequences for simulations of cometary and planetary atmospheres.