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MO: Molekülphysik

MO 57: Poster: Cold Molecules

MO 57.3: Poster

Donnerstag, 16. März 2006, 16:30–18:30, Labsaal

Sympathetic cooling of singly-protonated polyatomic molecules to sub-Kelvin temperatures — •Bernhard Roth, Chaobo Zhang, David Offenberg, Alexander Wilson, Alexander Ostendorf, and Stephan Schiller — Heinrich-Heine-Universität Düsseldorf

Alexa Fluor 350, a fluorescent dye molecule of mass 410 AMU, has been transferred from an electro spray ionisation (ESI) source to a linear Paul trap, via a 2-m long octopole ion guide. Around 2300 laser-cooled ¹³⁸Ba⁺ ions in a Coulomb crystal were used to sympathetically cool approximately 600 Alexa Fluor ions to below 100 mK. The sympathetically cooled ions are identified by monitoring the resonance fluorescence of the ¹³⁸Ba⁺ ions during secular excitation. Observations are well described by molecular dynamic simulations, which are used to determine the number of ions, their spatial distribution and translational temperature. The ESI technique should allow many different kinds of molecules to be transferred for trapping and sympathetic cooling: of particular interest may be molecules of very high mass and those of biological relevance, indeed, Alexa Fluor 350 is usually used in biological studies for protein labelling.