Optogalvanic observation of the CO W 1Π–B 1∑+ transition

The rotational structure of the W 1Π–B 1∑+ (0–0) band was resolved and the values of spectroscopic parameters were derived as B′0 =1.5549±0.0068 cm−1, r0=0.1257±0.0003 nm, and ν00=15 891.6±0.6 cm−1. The observation of the W 1Π–B 1∑+ (0–0) band supports Ogawa and Ogawa’s assignment that the W 1Π state is the first member of the nsσ Rydberg series converging to the A2 Πi state of CO+ ion. The W 1Π–B 1∑+ (1–0) band, on the other hand, was not observed with expected intensity and the presence of dissociative perturbation has been suggested.