ELECTRON-IMPACT DISSOCIATION OF HYDROGEN MOLECULE - TIME-RESOLVED MEASUREMENTS OF THE BALMER LINE

The time-resolved Balmer beta-line produced in e-H-2 collisions was measured to separate H*(4s) from H*(4p) and H*(4d). The time-resolved excitation function of H*(4s) started to decrease at an electron energy of about 40 eV compared to the excitation function of H*(n = 4). This decrease indicated that a new dissociation process, which did not produce H*(4s), opened at this energy. The translational energy distribution of H*(4s) obtained from the time-resolved Doppler profile had a dip at about 4 eV. This dip indicated that the new dissociation process, which did not produce H*(4s), produced H*(4p) and H*(4d) with a translational energy of about 4 eV. The new dissociation process proceeds through Q2 excited states.