Berlin 2001 – scientific programme

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A: Atomphysik

A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)

A 12.32: Poster

Thursday, April 5, 2001, 12:30–15:00, AT3

Associative Ionization in Low Energy Collisions of Atomic Hydrogen with rare gas atoms — •P. Wilhelms and B. Brehm — Institut für Atom- und Molekülphysik, Abteilung Atomare Prozesse, Universität Hannover

It is well known that rare gas atoms R and protons form strongly bound ions RH⁺ . These ions can be produced in collisions between hydrogen atoms and metastable rare gas atoms and this has been a field of research for many years[1].

We have recently successfully observed the associative ionization in collisions of atoms in their groundstates:

Associative ionization appears to be limited to collision energies below 15 eV. From the threshold the cross section rises to a maximum before breaking off at an energy below 15 eV. We find an energy gap between this breakoff and the onset of other ionization processes in which no ions are observed. For the process

the maximum is observed at 11.9 eV and has a value of 5·10⁻¹⁸ cm² .

[1] H. Hotop et al, J. Phys. B: At. Mol. Opt. Phys. 27 (1994) 4973-4990