Emission spectrum of the CN(B 2Σ+–X 2Σ+) tail band system: B 2Σ+∼4Π perturbations in the v B=9, 12, and 17 levels

Abstract

The CN(B 2Σ+–X 2Σ+) tail band system was observed in the reaction of argon metastable atoms with BrCN. The observed transitions in the 17-14 and 17-16 bands were analyzed in terms of the B 2Σ+,v=17∼A 2Πinv,v=34 and 4Π,v=p+11 perturbations, and the molecular constants for these levels and the interaction constants were determined. Intensity anomalies were also observed in the 9-8, 9-9, and 12-12 bands. The quantum numbers of the total angular momentum, J, of the perturbed rotational levels of B 2Σ+ were assigned as (vB,N;J)=(9,56;55.5) and (12,10;10.5). The vibrational quantum number was determined as p=0, and the crossing spin sublevels at the anomalies of vB=9 and 12 were determined as 4Π5/2 and 4Π1/2 by examination of the electronic part of the B 2Σ+∼4Π perturbation constant, HSOel, for the (vB,vΠ)=(14,6) and (17,11) perturbations estimated by use of the Rydberg–Klein–Rees (RKR) potentials for B 2Σ+ and 4Π.