High-resolution measurements and multichannel quantumdefect analysis of the Kr(4p5(2P1/2)nd', J = 2,3)autoionizing resonances

Abstract

Using two-step laser excitation of metastable Kr(4p55s 3P2,0) atoms via selected Kr(4p55p J = 1,2) levels, we haverecorded the low-lying autoionizing resonances Kr(2P1/2 nd', J = 2,3) (n = 6,7) at high resolution in two different experiments(atomic beam spectroscopy and optogalvanic spectroscopy in a discharge).Accurate values for the resonance positions (quantum defects) and the(reduced) widths have been determined and profile indices are reported.For comparison, multichannel quantum defect theory (MQDT) analyses,using energy-dependent MQDT parameters, have been carried out for theodd Kr(J = 1,2,3) levels, yielding good agreement in the quantumdefects and partial agreement in the predicted reduced widths for thend' resonances with the experimental values. Moreover, simplifiedphase-shifted quantum defect theory analyses of the measured bound oddKr(J = 2 and 3) Rydberg levels were carried out with the aimof providing improved insight into the dominant decay mechanism of the resonances.We also present a summary and comparative discussion of the reducedwidths for the nd'[K]J resonances of all the rare-gas atoms Ne,Ar, Kr and Xe.