FAR-ULTRAVIOLET EMISSION CROSS-SECTIONS OF NE-II AND NE-III EXCITED BY ELECTRON-IMPACT

We have measured the electron-impact-induced fluorescence spectrum of neon in the wavelength range 120-270 nm at a spectral resolution of 0. 43 nm (FWHM). The strongest lines observed in the far-ultraviolet (FUV ) spectrum of neon are assigned to terms of the doublet system of Ne I I (2s(2)2p(4)nl) and the triplet system of Ne III (2s(2)2p(3)3l). Our FUV spectral data, obtained at 300 eV electron-impact energy, provide absolute emission cross sections of these Ne II and Ne III lines, and are compared to previous measurements where available. In addition, th e excitation function of the strongest Ne II line observed at 191.6 nm was measured from threshold to 1000 eV electron-impact energy.