High-resolution electron-impact emission of H-2. I. Cross sections and emission yields 900-1200 angstrom

High-resolution (Delta lambda = 115 m Angstrom) emission spectra of molecul ar hydrogen produced by electron-impact excitation at 100 eV have been obta ined in the wavelength range 900-1200 A. The emission spectra can be assign ed to transitions between the X (1)Sigma (+)(g) ground state and the 1s sig ma (g)np sigma (1)(u)Sigma (u), and 1s sigma (g)np pi, (1)Pi (u) Rydberg st ates. Synthetic rotational line spectra based on the excitation function of Liu et al. and calculated 2p sigma B (1)Sigma (+)(u)-X (1)Sigma (+)(g), 2p pi C (1)Pi (u)-X 1 Sigma (+)(g), 3p sigma B' (1)Sigma (+)(u)-X (1)Sigma ()(g) and 3p piD (1)Pi (u)-X (1)Sigma (+)(g) transition probabilities of Abg rall et al. are generally found to be in good agreement with the experiment al spectra in the regions where emissions from 1s sigma (g) np sigma (u) (n greater than or equal to 4) and 1s sigma (g) np pi (u) (n greater than or equal to 4) states are negligible. Emission cross sections for D (1)Pi (+)( u), D' (1)Pi (u), and D " (1)Pi (-)(u), B' 1 Sigma (+)(u), and B " (1)Sigma (+)(u) states are obtained by measuring the emission intensities from thes e states relative to those from the B (1)Sigma (+)(u),C (1)Pi (u), and D (1 )Pi (-)(u) states. A high- resolution EW calibration technique is establish ed. At 100 eV the emission cross sections of the D (1)Pi (u), D' 1 Pi (u), D " (1)Pi (u), B' 1 Sigma (+)(u), and B " (1)Sigma (+)(u) states are measur ed to be (2.8+/-0.4) x 10(-18), (6.3 +/- 1.3) x 10(-19), (5.9 +/- 1.7) x 10 (-20), (2.1 +/- 0.3) x 10(-18), and (1.6 +/- 0.4) x 10(-19) cm(2), respecti vely. In addition, the vibrational emission cross sections have been compar ed to the estimated excitation cross sections to obtain the predissociation yields for selected vibrational levels of the D (1)Pi (+)(u), D' (1)Pi (+) (u) and D " (1)Pi (+)(u) states. The B' (1)Sigma (+)(u) state is inferred t o have very significant excitation into the H(1s)+H(2p, 2s) dissociative co ntinuum.