Electron induced fluorescence of the H₂molecule—Balmer lines and Fulcherαsystem

Abstract

We report results of an experimental study focused on the fluorescence of H 2 initiated by the impact of quasimonochromatic electrons. The emission spectra of H 2 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 H 2 . In addition to the atomic lines and molecular bands, the presence ofu 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 H 2 (d 3 Π u → a 3 Σ + g ) 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.