Observed and Predicted New Autoionized Energy Levels in Krypton, Argon, and Xenon

The absorption spectrum of argon and krypton has been investigated between 400-600 Å. Discrete structure is observed which can be related to the excitation of an inner $s$ electron. Configuration interactions between the discrete excited levels and the overlapping ionization continuum leads to autoionization of the energy levels, as evidenced by the fact that the measured photoionization yield within the discrete structure is 100%. The first member of the series is observed at 466 Å for argon and 497 Å for krypton with a predicted value of 593 Å for xenon. The Rydberg series $\nu =235\mathrm{}832-\frac{R}{{\mathrm{}(n-1.53\mathrm{})\mathrm{}}^2}$, $n=4, 5, \cdots$, etc., describes the argon data while similar series are predicted for krypton and xenon with quantum defects equal to 2.53 and 3.53, respectively, and using the appropriate term value for their respective $N_1$ and $O_1$ absorption edges.