Rotational analysis of the Ångström system (B1Σ+ - A1Π) in the rare 13C17O isotopologue.

Although yet unobserved in the very rare 13C 17O isotopologue, the ngström system (B 1Σ +-A 1Π) was obtained under high resolution as an emission spectrum using a conventional spectroscopic technique. The emission from the discharge was observed with a plane grating spectrograph and recorded by a photomultiplier tube. In total, 192 transition wave numbers belonging to two bands (0-1 and 0-2) were precisely measured and rotationally analyzed. This method allowed us to determine the merged rotational constants B 0 = 1.8131941(58) cm -1 and D 0 = 5.5620(46) × 10 -6 cm -1 and the individual molecular constant B 1 = 1.471059(47) cm -1, D 1 = 5.315(64) × 10 -6 cm -1, B 2 = 1.451762(13) cm -1, D 2 = 7.812(16) × 10 -6 cm -1 for the as yet unanalyzed 13C 17O molecule B 1Σ + and A 1Π states, respectively. The band origins σ0 - v″ of the ngström system in the 13C 17O molecule were also calculated. Numerous rotational perturbations observed in the A 1Π state in 13C 17O molecule have been identified and analyzed in detail. The suspected candidates responsible for these irregularities were indicated by means of a graph of the rovibronic levels of the neighboring states based on the estimated term value in the 13C 17O molecule. The values of these perturbations have also been defined for both the e- and f-parity of the A 1Π(v = 1 and 2) state. Simultaneously, the B 1Σ + state was observed to be quite regular up to the observed J max level. © 2012 Elsevier Inc.