Rotational perturbations in the CN(B2Σ+–X2Σ+) tail band system. III. Molecular constants for the 4Π, 4Σ+, A2Πi, and X2Σ+ states

Abstract

The CN(B2Σ+–X2Σ+) tail band system was observed by using the dissociative excitation reactions of HCN and BrCN with Ar(3P0.2) in an argon flowing afterglow. The following intensity anomalies owing to the B2Σ+ ~ 4Π rotational perturbations were analyzed: (νB, ν11) = (9,x), (11,x + 2), and (18,x + 13), where x is estimated to be 0 or 1. These anomalies, as well as(νB, ν11) = (12,x + 3), (14,x + 6), and (17,x + 11), were analyzed by spectral simulation. The CN(B2Σ+–X2Σ+) 14–14 band spectrum observed by Jenkins was re-analyzed, and the molecular constants for the perturbing 4Π state, the interaction constants, and the crossing schemes for the B2Σ+ ~ 4Π perturbations were determined. The intensity anomalies due to the perturbations by the 4Σ+, A2Πi, and X2Σ+ states were also observed: (νB, νΣ) = (15,p + 6), where p is estimated to be 8 ± 1, (νB, νA) = (11, 26) and (17, 34), and (νB, νX) = (11, 28). The molecular constants for the perturbing levels were estimated by a simulation analysis.