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

The technique of synchronization between the pulses of a linear dye laser, synchronously pumped by a mode-locked laser, and the synchrotron radiation pulses from the SuperACO storage ring in Orsay (France) has been applied to study the photoionization of the Xe* and Xe* excited states in the energy region between the and thresholds. The experimental spectra are dominated by strong transitions to the Xe* 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 and ( n = 7 - 9) resonances, the asymmetry parameter q and the linewidth could be determined upon photoexcitation from the intermediate state 5d and 6d , respectively. As a general behaviour of the investigated excitations, the oscillator strengths for transitions were found to exceed by far those for the, also dipole-allowed, transitions.