he atomic spectra observed in the pure noble gases are interpreted through the dominant processes of direct excitation by alpha and electron impact, trapping of vacuum ultraviolet resonance radiation, and excitation transfer effects resulting from two-body collisions with ground state atoms. The pressure dependence of helium line intensities may be explained with transfer cross-sections that are in reasonable agreement with earlier measurements by Maurer and Wolf. The absolute Intensities emitted from helium are in approximate agreement with cross-sections calculated from the Born approximation if allowance is made for these collisions effects. The results indicate that the light emitted from atomic transitions in all of the noble gases in the range between 2400 and 5500 represents a negligible fraction of the total excitation No evidence was found for a recombination spectrum in any of the gases. The weak lines observed in pure helium and neon were identified as atomic transitions which are normally present in the discharge spectrum at low pressures.
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