High-resolution far ultraviolet emission spectra of electron-excited molecular deuterium

The high-resolution (full width at half maximum = 0.11 A) emission spectrum of the deuterium molecule produced by electron-impact excitation at 100 eV has been measured in the wavelength range 1200 - 1660 A. In conjunction with the experimental measurement, transition probabilities of and D band systems are calculated. Synthetic spectra based on the calculated transition probabilities are in very good agreement with the optically thin experimental spectra. While centrifugal effects on the overall Lyman band emission intensity in D2 and H2 are similar, the effect of rotation-vibrational perturbations between the B 1u+ and C 1u+ states on spectral intensities is found to be less significant in D2. Excitations via isotropic ( J = 0) and anisotropic ( J = ±2, and 0) interactions for the dipole forbidden E, F 1g+-X 1g+ transition are inferred from the measured spectra. Excitation cross sections of the B 1u+-X 1g+ and C 1u-X 1g+ bands, along with the estimated E, F 1g+-B 1u+ cascade cross section, for D2 are obtained.