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

Time-resolved Fourier transform spectroscopy was applied to the study of He2 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 b3Π state produced efficiently in afterglow plasma have been identified. Rotational assignments and a least-squares analysis for the h3Σu+–g3Σg+ and g3Σg+–d3Σu+ bands in the 3200 cm−1 region were carried out to determine the molecular constants. A new band from an unidentified state to the d3Σu+ state has been observed in the 6300 cm−1 region with irregular P- and R-branch intensities.