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arXiv · 0810.0405

Spectroscopy and dissociative recombination of the lowest rotational states of H3+

A. Petrignani·H. Kreckel·M. H. Berg·S. Altevogt·D. Bing·H. Buhr·M. Froese·J. Hoffmann·B. Jordon-Thaden·C. Krantz·M. B. Mendes·O. Novotný·S. Novotny·D. A. Orlov·S. Reinhardt·A. Wolf
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Abstract

The dissociative recombination of the lowest rotational states of H3+ has been investigated at the storage ring TSR using a cryogenic 22-pole radiofrequency ion trap as injector. The H3+ was cooled with buffer gas at ~15 K to the lowest rotational levels, (J,G)=(1,0) and (1,1), which belong to the ortho and para proton-spin symmetry, respectively. The rate coefficients and dissociation dynamics of H3+(J,G) populations produced with normal- and para-H2 were measured and compared to the rate and dynamics of a hot H3+ beam from a Penning source. The production of cold H3+ rotational populations was separately studied by rovibrational laser spectroscopy using chemical probing with argon around 55 K. First results indicate a ~20% relative increase of the para contribution when using para-H2 as parent gas. The H3+ rate coefficient observed for the para-H2 source gas, however, is quite similar to the H3+ rate for the normal-H2 source gas. The recombination dynamics confirm that for both source gases, only small populations of rotationally excited levels are present. The distribution of 3-body fragmentation geometries displays a broad part of various triangular shapes with an enhancement of ~12% for events with symmetric near-linear configurations. No large dependences on internal state or collision energy are found.

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A. Petrignani, H. Kreckel, M. H. Berg, S. Altevogt, D. Bing, H. Buhr, M. Froese, J. Hoffmann, B. Jordon-Thaden, C. Krantz, M. B. Mendes, O. Novotný, S. Novotny, D. A. Orlov, S. Reinhardt, A. Wolf. 2008-10-02. Spectroscopy and dissociative recombination of the lowest rotational states of H3+. https://doi.org/10.1088/1742-6596/192/1/012022

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