Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 13: Photoionisation I (joint session A and MO)
A 13.2: Vortrag
Donnerstag, 5. April 2001, 16:00–16:15, H1012
Measurement of the First Ionization Potential of Actinium by Resonance Ionization Mass Spectrometry (RIMS) — •P. Kunz2, A. Waldek1, N. Erdmann1, C. Grüning1, G. Huber2, J.V. Kratz1, J. Lassen2, G. Passler2, N. Trautmann1, and K. Wendt2 — 1Institut für Kernchemie, Universität Mainz, Fritz-Strassmann-Weg 2, 55128 Mainz — 2Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz
Due to radioactivity hazard and readioactive decay only small samples of actinides can be used for spectroscopic investigations. We present a continuation of a systematic determination of the first ionization potential (IP) of actinides using samples of < 1012 atoms. With a modified RIMS method based on 3-step laser ionization in presence of a variable electric field the IP can be determined for the limit of a vanishing field. Recently the IP of the actinides up to einsteinium have been determined with this method by our group except for actinium and protactinium. For the measurement of actinium a stable atomic beam was produced from an electrolytically deposited Ac-hydroxide sample. For efficient atomization this sample was covered with Zr as a reducing agent. The ionization signals have been extrapolated to the vanishing field which is the accurate value of the IP by correcting for a fixed stray electric field in the experimental setup. In this way the IP of actinium has been measured for the first time .