Hannover 2003 – wissenschaftliches Programm

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A: Atomphysik

A 17: Postersitzung 2

A 17.8: Poster

Donnerstag, 27. März 2003, 16:00–18:30, Poster

Oscillatory pattern in spectra of photoelectrons produced by photodetachment — •Igor Kiyan, Rainer Reichle, Dag Hanstorp, and Hanspeter Helm — Fakultät für Physik, Albert-Ludwigs-Universität, D-79104 Freiburg

An imaging technique is used to record energy and angle resolved spectra of electrons produced by photodetachment of F⁻ in a strong infrared laser pulse. The spectra are measured at different laser frequencies in the range where the lowest order process requires absorption from 4 to 6 photons to overcome the detachment threshold. The spectra reveal an oscillatory behavior of the electron distribution as a function of the kinetic energy, which gradually evolves with the change of the frequency. As a part of the oscillatory pattern, each spectrum exhibits at higher energies a plateau localized along the laser polarization axis. A Keldysh-like theory is able to qualitatively describe the observed features in the spectra without taking into account the re-scattering of the photoelectron on the residual core. The parity of the initial state of the negative ion is shown to be of great importance in the description of the experimental results.