Resonances in the Photo-Ionization Continuum of Ne I (20-150 eV)

The absorption spectrum of neon in the region 20-150 eV has been studied photographically and photoelectrically, using synchrotron light as a background source. Discrete structure has been observed in three distinct energy ranges. The first is between the ²P^∘1/2, 3/2 limits near 22 eV, involving resonances analogous to those observed by Beutler in Ar, Kr, and Xe; the second is the region between 44 and 60 eV, the structure here being classified as due to two types of excitation: (i) the excitation of a subshell $2s$ electron, (ii) the simultaneous excitation of two outer $2p$ electrons; the third region is near 80 eV, where two weak resonances are observed, due to the simultaneous excitation of a subshell $2s$ and a $2p$ electron. The resonance profiles of the states 2s2p⁶np¹P^∘₁, where n=3,4, and 5, and the two-electron excitation state 2p⁴(³P)3s3p¹P^∘₁ have been studied quantitatively and values of q, Γ, and ρ determined for each.