Energy-transfer processes in neon-hydrogen mixtures excited by electron beams.

Energy- and charge-transfer processes in neon-hydrogen mixtures (500–1400 hPa neon and 0.001–3 hPa hydrogen partial pressures) excited by a pulsed low-energy (∼10 keV) electron beam were investigated using time-resolved spectroscopy. Time spectra of the hydrogen Lyman-α line, neon excimer emission (second continuum), and neon atomic lines (3p–3s transitions) were recorded. The time-integrated intensity of the Lyman-α emission was measured for the same range of gas mixtures. It is shown that direct energy transfer from Ne₂^* excimers and neon atoms in the four lowest excited states as well as recombination of H₃⁺ ions are the main channels populating atomic hydrogen in the n=2 state. A rate constant of (4.2±1.4)×10^-11 cm³ s^-1 was obtained for the charge transfer from Ne₂⁺ ions to molecular hydrogen. A lower limit for the depopulation rate constant of Ne₂^* excimers by molecular hydrogen (combination of energy transfer and ionization) was found to be 1.0×10^-10 cm³ s^-1. [ABSTRACT FROM AUTHOR]