Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 37: Cold Molecules III
Q 37.3: Vortrag
Mittwoch, 16. März 2011, 17:00–17:15, BAR Schön
Threshold photodetachment thermometry for cold molecular anions — •Alexander von Zastrow1, Thorsten Best1, Rico Otto1, Stephanie Eisenbach1, Martin Stei3, Sebastian Trippel1, Matthias Weidemüller2, and Roland Wester3 — 1Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — 2Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg — 3Institut f. Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25/3, A-6020 Innsbruck
During photodetachment an anion’s excess electron is lifted from a bound to a continuum state. The cross section for this process reveals information about the internal structure of the anion and the neutral as well as long range electron-neutral interactions.
One of the best studied molecular anions is OH−. At threshold the photodetachment cross section is sensitive to the different occupied rotational levels. From their contribution to the cross section, the anions’ rotational temperature can be derived. In our experiments ions are stored and sympathetically cooled in a 22-pole radiofrequency trap which can be operated between 8 K and 300 K. To determine the ions’ rotational temperature, we measure the absolute photodetachment cross section using a previously reported laser depletion tomography method [1,2].
This will allow us to investigate the efficiency of collisional cooling of internal degrees of freedom in future experiments.
S. Trippel et al., Phys. Rev. Lett. 97, 193993 (2006)
P. Hlavenka et al., J. Chem. Phys. 130, 061105 (2009)