Threshold photoelectron spectroscopy of cyanogen bromide

A high-resolution (2–15 meV) threshold photoelectron (TPE) spectroscopic study of BrCN was performed using synchrotron radiation and a penetrating-field electron spectrometer over the outer valence ionization region of the molecule. Significant differences were found between the TPE spectrum and the published high-resolution (∼6 meV) HeI photoelectron spectrum of BrCN [Chem. Phys. 212 (1996) 457]. Autoionization of Rydberg states and the 6σ valence state of BrCN were found to be primarily responsible for the formation of the observed band systems of BrCN+ in this study.