A 2+1 REMPI STUDY OF THE E-X TRANSITION IN CO - INDIRECT PREDISSOCIATIONS IN THE E(1)PI STATE

In this study 2+1 resonance enhanced multiphoton spectra of the E(1)II(nu=1, 0)-X(1) Sigma(+) (nu=0) transitions in (CO)-C-12-O-16, (CO)-C-13-O-16, (CO)-C-12-O-18 and (CO)-C-13-O-18 have been recorded in the laser wavelength range, 210-216 nm, and rotationally analysed. Perturbations have been observed in both the e and f parity levels of the E(1)II(nu=1) state which have the characteristics of an indirect predissociation similar to the well-known accidental predissociation in the J(e)=31 level of (CO)-C-12-O-16 (E(1)II, nu=0). The present results favour a (II)-I-3 valence perturbing state which is itself predissociated by a (II)-I-3 repulsive state correlating to the lowest dissociation limit; C(P-3)+O(P-3). Lambda doubling constants for all four isotopes in both the nu=0 and nu=1 vibrational levels of the E(1)II state have also been obtained.