31 May 2007
Andrey Kazansky and Nikolai Kabachnik of the Universität Bielefeld, Germany, offer a theoretical description of atomic photoionization by attosecond XUV pulses in the presence of an intense laser pulse (2007 J. Phys. B: At. Mol. Opt. Phys. 40 2163-2177).
The theoretical description is based on numerically solving the non-stationary Schrödinger equation. The researchers suggest an algorithm that can solve this problem with quite moderate computer facilities, which forms part of their ongoing effort to develop a robust and accurate theoretical description of the photoionization process.
When comparing the calculated energy spectra and photoelectron angular distributions with those obtained using a simple model based on the strong-field approximation, Kazansky and Kabachnik found an excellent agreement for a large range of photoelectron energies.
However, when the photoelectron energy is small and/or the intensity of the IR laser is large, the rescattering of the emitted electron by the ionic core becomes important and this makes the simple model inadequate.
The researchers also investigated the influence of the electron orbital polarization on the ionization cross section, and found that it plays a minor role in these conditions.
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