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Universität zu Köln
Mathematisch-Naturwissenschaftliche Fakultät
Fachgruppe Physik

I. Physikalisches Institut


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Double resonance rotational action spectroscopy


The double resonance rotational action spectroscopy scheme is a method that can be used to bring well established rovibrational schemes to the pure rotational domain. It works on the principle of redistributing the rotational population of the studied molecule ensemble (1. photon, usually THz radiation), effectively influencing the second action spectroscopy method, responsible for the signal detection. Wide range of schemes can be applied as a second process e.g. laser induced reactions (LIR), the messenger tagging technique, or the infrared multiphoton dissociation (IRMPD). ...more


Schematic view of a 22-pole trap setup with IR laser and THz radiation used for double resonance rotational action spectroscopy. An elliptical THz mirror with a 1 mm hole is used to combine both radiations.


COLTRAP and FELion are two new generation 22-pole ion trap instruments developed and built in our laboratory. Both instruments offer unique possibilities to study the kinetics of ion-molecule reactions at low temperatures, and to use highly sensitive methods for spectroscopic studies of molecular ions. Whereas the COLTRAP instrument is located in the Cologne laboratories, FELion has been installed in October 2014 at the FELIX Laboratory (Radboud University Nijmegen, Netherlands).
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