Line shapes of atomic hydrogen in hollow-cathode discharges

Abstract

Emission lines of atomic hydrogen produced in the hollow cathode of an electric glow discharge are found to have articulated line shapes indicating three quite different excitation mechanisms for the emitting atoms. Particularly striking is the extensive development of the far wings, which have Gaussian line shapes with FWHM values attaining 10 cm(-1) or more. This corresponds to an atomic kinetic energy greater than 100 eV and suggests an origin for such energy in the cathode-fall region.