Mainz 2017 – scientific programme
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A: Fachverband Atomphysik
A 16: XUV/X-ray spectroscopy III
A 16.3: Talk
Tuesday, March 7, 2017, 15:15–15:30, N 2
Electron correlation meets high-harmonic generation in He: Identifying plateaus beyond 3.17 Up in the simulation — •Julius Rapp, Martins Brics, and Dieter Bauer — Institute of Physics, University of Rostock, 18051 Rostock, Germany
The harmonic radiation generated by an atom with ionization potential Ipn+ subjected to a laser field of ponderomotive energy Up is classically expected to reproduce the cutoff energies of 3.17 Up + Ipn+ considering a single active electron (SAE) at each ionic charge number n. Beyond the SAE, electron correlation may give rise to new phenomena such as nonsequential double recombination [1] where—in simple man’s picture—double ionization is followed by the simultaneous recombination of two electrons. Apart from those subtle yet qualitative additions, electron correlation may influence the ionization probabilities to such an extent that the contributions from different ionic charge states to the harmonic yield are significantly modified.
We present high-harmonic spectra of helium obtained by the numerical propagation of renormalized natural orbitals (RNOs) in 3D. Indeed, time-dependent RNO theory (TDRNOT) [2] applied to helium in full dimensionality produces harmonic-radiation plateaus which can not be explained in the SAE picture (confirming the prediction from 1D simulations [2]). We finally illustrate the disentanglement of different possible explanations by extended simple-man’s modeling and time-frequency analyses.
[1] P. Koval, F. Wilken, D. Bauer, C. H. Keitel, PRL 98, 043904 (2007)
[2] M. Brics, J. Rapp, D. Bauer, PRA 93, 013404 (2016)