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

Although yet unobserved in the very rare (CO)-C-13-O-17 isotopologue, the Angstrom system (B-1 Sigma(+)-A(1)Pi) 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) x 10(-6) cm(-1) and the individual molecular constant B-1 = 1.471059(47)cm(-1), D-1 = 5.315(64) x 10(-6) cm(-1), B-2 = 1.451762(13) cm(-1), D-2 = 7.812(16) x 10(-6) cm(-1) for the as yet unanalyzed (CO)-C-13-O-17 molecule B-1 Sigma(+) and A(1)Pi states, respectively. The band origins sigma(0-nu') of the Angstrom system in the (CO)-C-13-O-17 molecule were also calculated. Numerous rotational perturbations observed in the A(1)Pi state in (CO)-C-13-O-17 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 (CO)-C-13-O-17 molecule. The values of these perturbations have also been defined for both the e- and f-parity of the A(1)Pi( v = 1 and 2) state. Simultaneously, the B-1 Sigma(+) state was observed to be quite regular up to the observed J(max) level. (C) 2011 Elsevier Inc. All rights reserved.