Extended analysis of the Ångström band system (B1Σ+ - A1Π) in the rare12C17O isotopologue.

The Ångström band system (B 1Σ + A 1Π), so far unobserved in the rare 12C 17O isotopologue, was obtained under high resolution as an emission spectrum using high accuracy dispersive optical spectroscopy. In total, 200 transition wave numbers belonging to the 0-1 and 0-2 bands were precisely measured and rotationally analysed. The obtained result was the merged rotational constants B 0 = 1.8988823(41)cm 1 and D 0 = 6.4283(26) × 10 6 cm 1 for the B 1Σ + Rydberg state as well as the individual rotational constants B 1 = 1.54088(12)cm 1, D 1 = 6.950(87) × 10 6cm 1, B 2 = 1.519292(69)cm 1, D 2 = 8.22(16) × 10 6cm 1 for the A 1Π state in the 12C 17O isotopologue. The band origins were also calculated. Numerous rotational perturbations observed in the A 1Π state in this molecule have been identified. The observed perturbations were confronted with those predicted from theoretical calculations. © 2012 IOP Publishing Ltd.