München 2004 – scientific programme

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A: Atomphysik

A 15: Poster 2

A 15.22: Poster

Thursday, March 25, 2004, 14:00–16:00, Schellingstr. 3

A high-resolution detector for charge transfer experiments involving ultracold atoms — •Wenzel Salzmann, Helmut Rathgen, Roland Wester, and Matthias Weidemüller — Physikalisches Institut, Universität Freiburg, 79104 Freiburg

We are setting up a new experiment to study ion-atom collisions using lasercooled atoms as an ultracold target. Projectile ions with energies of eV - keV pass through a magneto-optical trap where rubidium atoms are stored at temperatures below 100µK[1]. Target atoms which are ionised in the collision are momentum-analysed using Recoil-Ion-Momentum-Spectroscopy (RIMS)[2]. The low target temperatures correspond to very low momentum spreads of the rubidium atoms (δ p < 0.01) which ensures a high resolution measurement of the recoil ion momentum components. We use this setup to examine several aspects of charge transfer reactions, in particular dissociative charge transfer to diatomic molecular ions at eV-keV energies. By using a defined projectile beam one can extract detailed information from the recoiled ion about the internal electronic state of the neutral molecule after the collision. The dissociated states are analysed by detecting the neutral fragments and their kinetic energy. In order to prepare the ions in a defined state they are stored in a linear electrostatic ion trap at keV energies or in a Rf-trap at eV energies. The status of the experiment is presented.

[1] M.v.d. Poel et al., Phys. Rev. Lett. 87, 12, 3202(2001).

[2] J.Ullrich et al., J. Phys. B,30, (1997), 2917-2974.