Experimental Determination of Oscillator Strengths for the CO A 1Π←X 1Σ+ Bands

The oscillator strengths for three bands $\text{(υ′\hspace{0.17em}=\hspace{0.17em}0, 1, 2)}$ in the transition $A^1{\mathrm{\Pi \hspace{0.17em}\leftarrow \hspace{0.17em}X}}^1{\Sigma }^{+}$ of carbon monoxide have been determined from electron impact spectra (taken at zero scattering angle) of mixtures of carbon monoxide and helium using the known oscillator strength for the $1^1{\text{S\hspace{0.17em}→\hspace{0.17em}2}}^{1}P$ transition in helium as a reference. The oscillator strength for the $\text{υ′\hspace{0.17em}=\hspace{0.17em}2}$ excited state ($\text{υ″\hspace{0.17em}=\hspace{0.17em}0}$ in the ground state) is 0.045 ± 0.005. This is to be compared with the value 0.0429 obtained by an entirely different method [E. N. Lassettre and A. Skerbele, J. Chem. Phys. 54, 1597 (1971)].