First observation of the CO E1Π to B1Σ+and C1Σ+to B1Σ+band systems. Predissociation in the E1Π(v=0) level

Abstract
The E1 Pi to B1 Sigma + and C1 Sigma + to B1 Sigma + (0-0) bands in the 12C16O and 14C16O molecules have been observed for the first time. The high resolution of the Fourier spectroscopy allowed the observation both of faint rotational perturbations and of accidental predissociations in the E1 Pi (v=0) vibrational level. Accurate molecular constants are derived for the observed levels.