Stuttgart 2012 – scientific programme
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MO: Fachverband Molekülphysik
MO 16: Collisions and Spectroscopy in He-Droplets
MO 16.6: Talk
Thursday, March 15, 2012, 11:45–12:00, V38.02
Time-Of-Flight and Velocity-Map-Imaging-Spectroscopy of Rubidium-doped Helium Nanodroplets — •Amon Sieg1, Lutz Fechner2, Barbara Grüner1, Marcel Mudrich1, and Frank Stienkemeier1 — 1Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany — 2Max-Planck-Institut für Kernphysik, 69029 Heidelberg, Germany
Helium nanodroplets provide an ideal matrix for spectroscopy of embedded atoms and molecules due to the low temperature conditions (0.4 K) and extremely weak interactions with the dopants. In our experiments we ionize rubidium atoms attached to helium nanodroplets via resonant 2-photon-ionization. With our time-of-flight mass spectrometer we are able to discriminate between neat Rb+ ions and RbHen+-exciplexes (n=1,2) which are formed upon excitation. The mass-resolved excitation spectra are in agreement with a pseudodiatomic model which treats the dopant atom as one and the whole helium droplet as the other atom of a diatomic molecule. From velocity-map-images (VMI) of photoelectrons and ions we extract energies and angular distributions which give detailed insight into the desorption process of excited Rb and RbHen off the droplets.