Vibrational Intensities of the A1Π←X1Σ+ Transition in Carbon Monoxide

The electron-impact spectrum of carbon monoxide has been investigated at electron energies of 400 and 200 V. The intensity distribution among vibrational levels of the A1Π←X1Σ+ transition has been studied as a function of the scattering angle and electron kinetic energy. The experimental data have been compared with theoretical predictions based on the Born approximation. The results indicate that in the range of the present measurements (θ<6°) the relative intensities are independent of the scattering angle. This observation agrees with the approximate theory of Craggs and Massey. The relative intensities agree fairly well with the Franck—Condon factors calculated by Nicholls except at high vibrational quantum numbers.