Time-resolved Fourier transform infrared emission spectroscopy of He2 produced by a pulsed discharge

Abstract Time-resolved Fourier transform spectroscopy was applied to the study of He 2 infrared emission produced by a pulsed discharge in pure He. In the 1800–8000 cm −1 region, new electronic bands have been observed in addition to the previously reported transitions. From the observed time profiles of emission spectra, Rydberg states with higher energy than the b 3 Π state produced efficiently in afterglow plasma have been identified. Rotational assignments and a least-squares analysis for the h 3 Σ u + – g 3 Σ g + and g 3 Σ g + – d 3 Σ u + bands in the 3200 cm −1 region were carried out to determine the molecular constants. A new band from an unidentified state to the d 3 Σ u + state has been observed in the 6300 cm −1 region with irregular P- and R-branch intensities.