Decay of an autoionizing Intruder State resolved in time

Polyelectronic atoms can exhibit autoionizing Rydberg series whose quantum defects and reduced widths change sharply with energy, due to the interaction between the main configurations of the series and a different configuration, energetically close to the series limit, known as intruder states. Modern time-resolved photoelectron spectroscopies offer the chance to resolve the decay of such intruder states in time. Here, the evolution of an intruder state is studied by solving the time-dependent Schroedinger equation on a grid for a 1D model with zero-range potentials. The intruder state, excited from the ground state by a short light pulse, decays first to a transiently-bound wavepacket, formed by several terms of the autoionizing series, and subsequently to the continuum. The characteristic times of these two stages of the decay are recognized in the dipole-transition amplitude from the ground state, which is analytically known. Preliminary results for the decay of intruder states in realistic atomic targets~[1,2] will also be presented. [1] L. Argenti et al., J. Phys. B 39, 2773 (2006). [2] K. Schulz et al., Phys. Rev. A 54, 3095 (1996).