A 2+1 REMPI study of the E-X transition in CO. Indirect predissociations in the E 1Π state

Abstract

In this study 2+1 resonance enhanced multiphoton spectra of the E 1Π(v=1, 0)-X 1Σ+(v=0) transitions in 12C16O, 13C16O, 12C18O and 13C18O have been recorded in the laser wavelenght range, 210–216 nm, and rotationally analysed. Perturbations have been observed in both the e and f parity levels of the E 1Π(v=1) state which have the characteristics of an indirect predissociation similar to the well-known accidental predissociation in the Je=31 level of 12C16O (E 1Π, v=0). The present results favour 3Π valence perturbing state which is itself predissociated by a 3Π repulsive state correlating to the lowest dissociation limit; C(3P)+O(3P). Lambda doubling constants for all four isotopes in both the v=0 and v=1 vibrational levels of the E 1Π state have also been obtained.