Hannover 2010 – scientific programme

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MO: Fachverband Molekülphysik

MO 10: Poster: Spectroscopy in He Droplets

MO 10.5: Poster

Tuesday, March 9, 2010, 16:00–18:30, Lichthof

Excitation spectroscopy of alkaline earth ion doped helium nanodroplets — •Raphael Katzy, Severin Müller, Marcel Mudrich, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg

In recent years helium nanodroplets have been successfully established as matrix for spectroscopy of atoms and molecules. In superfluid droplets particles are isolated and cooled down to the scale of millikelvin.

In our experiments we dope the droplets with singly charged alkaline earth ions using kHz laser ablation. Excitation spectra of the ions are recorded using laser-induced flourescence.

Ions bind nearby helium atoms tightly due to interaction with induced dipoles. A layered structure of high density emerges which is called snowball. On the other hand in the case of alkaline earth ions the left-over valence electron causes Pauli exchange repulsion. If this force is dominant an area of vanishing helium density is induced around the ion, a so called bubble.

To find out which of these counteracting mechanisms dominates LIF spectra are taken.