Photoionization spectroscopy of even-parity autoionizing Rydberg states of argon: Experimental and theoretical investigation of Fano profiles and resonance widths

Abstract

Using the $4{s}^{\ensuremath{'}}{[1/2]}_{0}$ and $4s{[3/2]}_{2}$ metastable states of argon created in a plasma discharge we perform photoionization spectroscopy of even-parity autoionizing $\text{Ar}(n{p}^{\ensuremath{'}})$ Rydberg states between the first and second ionization limits. Fitting the data to a sum of Fano-type or Shore-type profiles allows us to extract the widths and energies of the three overlapping resonance states ${[1/2]}_{1}$, ${[3/2]}_{1}$, and ${[3/2]}_{2}$ in the $11{p}^{\ensuremath{'}}$ manifold. We compare the experimental analysis of the $11{p}^{\ensuremath{'}}$ multiplet to theoretical calculations which are based on the configuration interaction Pauli-Fock approach with core polarization. Agreement between the experimental and theoretical resonance parameters is good.