Hamburg 2009 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 10: Kalte Moleküle 1
MO 10.4: Vortrag
Dienstag, 3. März 2009, 11:30–11:45, VMP 6 HS-G
Absolute photodetachment cross section measurements of the O− and OH− anion — •Petr Hlavenka1, Rico Otto1, Sebastian Trippel1, Martin Stei1, Matthias Weidemüller2, and Roland Wester1 — 1Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — 2Physikalisches Institut, Universität Heidelberg, Albert-Überle-Str. 3-5, 69120 Heidelberg
Almost all measurements of absolute photodetachment cross sections of anions can be traced
back to two studies on O−, which act as a calibration standard. Here we present
absolute total photodetachment cross sections of O− and OH− anions stored in a
multipole radiofrequency trap [1]. The O− cross sections 5.9(1) and
6.3(1)·10−18 cm2 measured at 662 nm and 532 nm, respectively, agree with
preceding experiments. A significant deviation is found compared to ab initio
calculations. For OH− the total cross sections measured at 662 nm and 632 nm, were
found to be constant in the temperature range 8-300 K. Using a novel laser depletion
tomography method we increase the accuracy of this calibration standard [2].
[1] S. Trippel et al., Phys. Rev. Lett. 97, 193003 (2006)
P. Hlavenka et al., submitted