Rotational perturbations in the CN(<i>B</i>²Σ⁺–<i>X</i>²Σ⁺) tail band system. III. Molecular constants for the ⁴Π, ⁴Σ⁺, <i>A</i>²Π_<i>i</i>, and <i>X</i>²Σ⁺ states

Abstract

The CN(B 2 Σ + –X 2 Σ + ) tail band system was observed by using the dissociative excitation reactions of HCN and BrCN with Ar( 3 P 0.2 ) in an argon flowing afterglow. The following intensity anomalies owing to the B 2 Σ + ~ 4 Π rotational perturbations were analyzed: (ν B , ν 11 ) = (9,x), (11,x + 2), and (18,x + 13), where x is estimated to be 0 or 1. These anomalies, as well as(ν B , ν 11 ) = (12,x + 3), (14,x + 6), and (17,x + 11), were analyzed by spectral simulation. The CN(B 2 Σ + –X 2 Σ + ) 14–14 band spectrum observed by Jenkins was re-analyzed, and the molecular constants for the perturbing 4 Π state, the interaction constants, and the crossing schemes for the B 2 Σ + ~ 4 Π perturbations were determined. The intensity anomalies due to the perturbations by the 4 Σ + , A 2 Π i , and X 2 Σ + states were also observed: (ν B , ν Σ ) = (15,p + 6), where p is estimated to be 8 ± 1, (ν B , ν A ) = (11, 26) and (17, 34), and (ν B , ν X ) = (11, 28). The molecular constants for the perturbing levels were estimated by a simulation analysis.