The presented results are concerned with the shapes of the Balmerhyphen;agr; line emitted by a lowhyphen;pressure rf 13.56hyphen;MHz discharge in hydrogen. Optical emission analysis has been done using a monochromator with a high spectral resolution (0.04 Aring;). Essentially, the lines present a central nearly Gaussianhyphen;shape peak with a FWHM of about 0.3 Aring; emerging from a wide pedestal constituted by two plateaus with widths equal to 0.9 and 1.5 Aring;, respectively, and by large wings whose intensity quasilinearly decreases on both sides of the central wavelength. We explain these profiles by the Doppler broadening due to fast H atoms produced by the dissociative excitation and the dissociative ionization of the H2molecules by electron impact generally followed by the excitation of the resulting atoms towards emitting states.
展开▼
