Osnabrück 2002 – wissenschaftliches Programm
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A: Atomphysik
A 18: Poster II
A 18.10: Poster
Donnerstag, 7. März 2002, 17:30–19:30, Schloss
Investigation of Autoionizing States in Rare Gases by Resonantly Enhanced Multi-Photon Ionization and Third Harmonic Generation — •Mattias Johnsson, Michael Stellpflug, Torsten Rickes, Thorsten Peters, Thomas Halfmann, and Klaas Bergmann — Fachbereich Physik der Universität, D-67663 Kaiserslautern
We examined experimentally the autoionizing states of Xenon by resonantly enhanced multi-photon ionization (REMPI) using different intermediate states as well as non-resonant third harmonic generation. The spectral line shape and Fano parameters for autoionization change significantly depending on the intermediate state and differ from the line profiles recorded in third harmonic generation as well as from previous data taken with one-photon ionization using UV synchrotron radiation.
For the intermediate state 5p5(2P3/2)6p[1/2]0, which belongs to a JC=3/2 core configuration, only nd’ resonances were observed in the ionization spectrum. For the 5p5(2P1/2)6p′[1/2]0 intermediate state, associated with a JC=1/2 core configuration, both nd’ and ns’ resonances could be seen.
The results for third harmonic generation also exhibited the signature of the nd′ and ns′ resonances. In contrast to previous one-photon synchrotron ionization data where a negative Fano q parameter was observed for the d resonances, our results yield a postive q parameter. These data demonstrate the strong dependance of the spectral line shape and Fano parameter upon the excitation pathway to the autoionizing state.