Absorption of Krypton in the Extreme Ultra-violet

Abstract

The far ultra-violet absorption spectra of the heavier inert gases are characterized by strong, diffuse lines in the region between the 2P3/2 and 2P1 2 series limits. These lines have large natural widths, owing to the high probability of auto-ionization of their upper levels. Their oscillator strengths have been measured in the case of krypton by photographic photometry, using a photomultiplier to calibrate the photographic plates. The f-values found, 0.04 for the strongest line and 0 10 for the sum of all the lines, are much smaller than had been expected on the basis of dispersion measurements. Rough measurements of the continuous absorption in krypton from the 2P1/2 series limit to 500 Å have been made directly with a photomultiplier, and it is shown that absorption in this continuum, the diffuse lines and the resonance lines probably accounts for only about two-thirds of the refractive index measured in the quartz ultra-violet region.