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A: Atomphysik

A 9: Poster 1

A 9.31: Poster

Dienstag, 23. März 2004, 14:00–16:00, Schellingstr. 3

Correlation effects of the 4s electron and the photoelectron in potassium after inner shell excitation — •Kyra Cole^1,2, M. Hertlein¹, A. Belkacem¹, B. Feinberg¹, J. Maddi^1,3, M. Prior¹, H. Adaniya^1,4 und R. Dörner² — ¹Lawrence Berekeley Labratory , Berkeley, CA 94720 USA — ²Institut für Kernphysik Johann Wolfgang Goethe Universtät , Frankfurt am Main — ³University of California, Berkeley — ⁴University of California, Davis

We use argon and potassium atoms as targets to study the interaction with hard x-rays. Since potassium features only an additional valence electron ([Ar] 4s¹ electron configuration) with respect to argon, the ionization dynamics of these two systems are comparable. We monitor the modifications of the electron configurations in both atomic species by measurements of ion yields of different charge states, following Auger decay after k-shell excitation. In our setup, the atoms are excited with 0.5 to 0.7eV bandwidth x-rays in the energy range of 3.1 to 3.7keV. Our apparatus consists of a time-of-flight spectrometer with pulsed-field ion extraction that allows measurements with a high signal-to-noise ratio, using ALS multibunch mode. For argon, our data gives clear evidence that recapturing of low-energy photoelectrons following Auger decay takes place. In contrast, our potassium data gives rise to a completely different behavior, which is caused by correlation effects between the 4s valence electron and the ejected photoelectron. The averaged charge states for argon and potassium are very similar far above the K-edge but differ significantly close to the K-edge region.