Two-photon double-resonant excitation of the Xe* autoionization states using synchronized laser and synchrotron radiation pulses

Abstract

The technique of synchronization between the pulses of a linear dye laser, synchronously pumped by a mode-locked Ar+ laser, and the synchrotron radiation pulses from the SuperACO storage ring in Orsay (France) has been applied to study the photoionization of the Xe* 5p55d [3/2]1 and Xe* 5p56d [3/2]1 excited states in the energy region between the Xe+ 5p5(2P3/2) and (2P1/2) thresholds. The experimental spectra are dominated by strong transitions to the Xe* 5p5nf′ [5/2]2 autoionization resonances, which are characterized by typical asymmetric Fano-type line profiles. The energy positions of the n = 4, 7-13 resonances have been measured. For the 4f′ [5/2]2 and nf′ [5/2]2 (n = 7-9) resonances, the asymmetry parameter q and the linewidth Γ could be determined upon photoexcitation from the intermediate state 5d [3/2]1 and 6d [3/2]1, respectively. As a general behaviour of the investigated excitations, the oscillator strengths for d → f transitions were found to exceed by far those for the, also dipole-allowed, d → p transitions.