Experimental and theoretical investigation of even mp⁵_1/2 np' autoionizing resonances of rare gas atoms

Using experimental set-ups involving single photon excitation of metastable rare gas atoms Rg(mp⁵(m + 1)s, J = 2, 0) by a pulsed frequency-doubled dye laser in conjunction with time-of-flight ion detection, we have investigated several even Rg(mp⁵_1/2 np') autoionizing resonances of the heavier rare gas atoms Rg = Ne − Xe (m = 2–5) at experimental bandwidths of 0.06 cm⁻¹ (Ne) and about 0.25 cm⁻¹ (Ar, Kr, Xe). New level energies (quantum defects) and widths for these resonances have been derived by a Fano-type lineshape analysis, thus yielding reduced resonance widths. The experimental spectra and the resonance parameters are compared with theoretical calculations which are based on the configuration interaction Pauli–Fock approach, including core polarization. For Rg = Ne, good agreement between the measured and the calculated results is observed. For the heavier rare gases, significant deviations between some of the existing experimental data and the theoretical results are found, indicating the need for further studies.