It has been observed that a dc, condensed, self-triggered helium discharge at high pressures (400—800 mm Hg) produces a strong continuous emission spectrum in the 1050–4000 Å region, with a broad intensity maximum around 2500 Å. In the same discharge, a continuum-like feature appeared in the 500–600 Å region because of the merging of the very greatly broadened resonance series lines with additional diffuse bands between the successive lines of the series. A suggestion is made concerning the origin of the observed continuum in the 1050–4000 Å region. A detailed description of experimental conditions producing the continuum is also presented.
A short description is also given of spectra of argon and xenon, which show additional continua similar to those of helium mentioned above.
R. E. HUFFMAN, Y. TANAKA, and J. C. LARRABEE, "New Vacuum-Ultraviolet Emission Continua of Helium Produced in High-Pressure Discharges," J. Opt. Soc. Am. 52, 851-857 (1962)