Electron induced fluorescence of the H2 molecule—Balmer lines and Fulcher α system

Abstract

We report results of an experimental study focused on the fluorescence of H2 initiated by the impact of quasi-monochromatic electrons. The emission spectra of H2 molecules at electron energies of 25 eV, 50 eV and 100 eV have been measured in the spectral range of 320–670 nm. The emission spectrum is dominated by Balmer emission lines, Fulcher α, β, γ and δ bands and different singlet transitions of H2. In addition to the atomic lines and molecular bands, the presence of continuum radiation is present in the whole studied range. We have determined the emission cross sections (ECS) for particular processes leading to the emission of the Balmer (n = 3, 4, 5, 6, 7, 8 → 2) lines and for selected bands of the Fulcher α system of H2(d3Πu → a3) as a function of electron energy in the range 5–100 eV. Emission cross sections for the Balmer lines (n = 6, 7, 8 → 2) and Fulcher α (1, 0), (1, 1), (2, 2), (3, 3) bands were measured for the first time.