Düsseldorf 2007 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 30: Poster: Spectroscopy in He droplets

MO 30.2: Poster

Dienstag, 20. März 2007, 16:30–18:30, Poster A

Doping of helium nanodroplets by high repetition rate laser ablation — •Benjamin Forkl, Severin Müller, Marcel Mudrich, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg, Germany

In recent years helium nanodroplets have been established as an almost ideal matrix for spectroscopical studies of atoms and molecules. By evaporation of helium atoms they can dissipate energy introduced by the species under study, thus cooling molecules and complexes down to millikelvin temperatures, well below the energy needed to excite the samples vibrational degrees of freedom. By sequential doping with different atoms the droplets can be used as nanoreactors to synthesize novel complexes, thereby extending the possibilities for spectroscopic studies. In the most straightforward fashion the droplets are doped by pick-up of dopant particles from the gas phase. Since thermal evaporation is hard to achieve for high refractory metals, ions or fragile biological molecules, a pulsed laser ablation source has been constructed. An ablation laser is focused on the dopant material, thus generating a plasma in the droplet formation region providing gas phase densities of atoms, molecules or ions to be picked-up by the droplet beam. First measurements are presented of the new ablation source employing a kHz repetition rate laser.