Observation of the a4Π and b4Σ − states of NO by electron-impact spectroscopy

Abstract

An electron-impact technique has been used to detect excitation of the a 4Π and b 4Σ − states of NO from the ground X 2Π state. The constants T 0, ω e , ω e x e , and R e of the b 4Σ − state are determined directly from the experimental observations; the 10 lowest vibrational levels being strongly excited at large scattering angles near threshold. The a 4Π state is more weakly excited and the lowest vibrational level is not detected. However, the above constants for this state have been obtained after a comparison of the relative energies and intensities of the a and b states which result from our observations, with the previously published emission spectra of the a 4Π ← b 4Σ − transition. A new vibrational numbering is proposed for the a and b states.