VIBRATIONAL REASSIGNMENT OF THE 2(1)SIGMA(+)(U)[-X(1)SIGMA(+)(G) TRANSITION OF CL-2

Spectra of the 2(1) Sigma(u)(+) (v') <-- X(1) Sigma(g)(+) (v '' = 0) transition of Cl-2 between similar to 78 000 and 80 100 cm(-1) have been recorded using a vacuum ultraviolet laser/time-of-flight mass spectrometer. Isotopomer assignments for the numerous features associated with each vibrational band in this spectral region have been established unambigously for the first time. Although the system appears perturbed, measured vibrational isotope shifts strongly support a change of +1 in the accepted 2-state v' numbering. Rotational line intensities in the 2 <-- X TOF spectra obtained by monitoring Cl-2(+) differ markedly from those obtained by monitoring Cl+. These results can be rationalized by invoking an additional resonant enhancement in the molecular TOF spectra due to superexcited states.