HIGH-RESOLUTION ELECTRON-IMPACT STUDY OF THE FAR-ULTRAVIOLET EMISSION-SPECTRUM OF MOLECULAR-HYDROGEN

The emission spectrum of molecular hydrogen produced by electron-impac t excitation at 100 eV has been measured in the wavelength range 1140- 1690 Angstrom. High-resolution, optically thin spectra (Delta lambda = 0.136 Angstrom) of the far-ultraviolet( FUV) Lyman and Werner band sy stems have been obtained with a newly constructed 3 m spectrometer. Sy nthetic spectral intensities based on the transition probabilities cal culated by Abgrall et al. are in very good agreement with experimental ly observed intensities. Previous modeling that utilized Allison & Dal garno band transition probabilities with Honl-London factors breaks do wn when the transition moment has significant J dependence or when re- vibrational coupling is significant. Ro-vibrational perturbation betwe en v = 14 of the B (1) Sigma(u)(+) state and v = 3 of the C (1) Pi(u), state and the rotational dependence of the transition moment in the ( 6, 12) and (7, 13) bands of the Lyman system are examined. Complete hi gh-resolution experimental reference FUV spectra, together with the mo del synthetic spectra based on the Abgrall transition probabilities, a re presented. An improved calibration standard is obtained, and an acc urate calibration of the 3 m spectrometer has been achieved.