Autoionizing even Rydberg series of Ne: a comparison of many-electron theory and experiment

The 2p51/2np' J = 0, 1, 2 and 2p51/2nf' J = 2 autoionizing Rydberg states (ARS) of Ne have been studied by two-step two-colour photoionization of ground-state neon atoms via the intermediate states 2p53/23s J = 1 and 2p51/23s' J = 1, followed by time-of-flight ion detection. Strong interference between the direct and virtual intershell photoexcitation channels in ARS production, especially for the np' J = 0 series, is revealed. The computed reduced width Γr = 6431cm−1 and the quantum defect μp = 0.7634 of the 2p51/213p' J = 0 resonance agree well with the experimental results Γ = 5334cm−1 and μp = 0.7662 determined with a Fano-type lineshape analysis. The measured lineshapes of the np' J = 0, 1, 2 resonances are also in good agreement with the many-electron computation.