Vibrational and rotational state distributions of CN(B 2Σ+) produced in collision of Xe(3P2) with CICN and BrCN

Abstract

Abstract The dynamics of the dissociative excitation of CICN and BrCN in collision with metastable Xe atoms, Xe m , is studied by the vibrational and rotational distributions of the CN(B 2 Σ + ) fragment produced in a Xe afterglow. The distributions determined by a simulation analysis of the CN(B 2 Σ + −X 2 Σ + ) violet emission spectra are compared with those produced in the dissociation of CICN and BrCN by photons of nearly equal excess energies, reported by Simons et al. A dominant mechanism for CN(B 2 Σ + ) formation is found to be the resonance excitation of the cyanides to the α-continuum or the B 3 Π state followed by dissociation. More vibrational and rotational energy is found to be partitioned to the CN(B 2 Σ + ) fragment produced by Xe m -impact dissociation, especially from BrCN. This is ascribed to a lengthening of the CN bond in XCN caused by interaction with the Xe m atom.