Hamburg 2009 – scientific programme

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A: Fachverband Atomphysik

A 34: Poster II

A 34.53: Poster

Thursday, March 5, 2009, 16:30–19:00, VMP 9 Poster

Photodissociation of the HeH⁺ molecular ion — •Irina Dumitriu and Alejandro Saenz — Humboldt-Universität zu Berlin, Institut für Physik, AG Moderne Optik, Hausvogteiplatz 5-7, D-10117 Berlin, Germany.

The HeH⁺ molecular ion has been of interest for astrophysics, for the tritium neutrino mass experiments, and in itself as a model system for a long time. More recently it has been drawing special attention due to an FEL experiment (FLASH) performed at DESY, in Hamburg [1].

The Hamburg experiment motivates the calculation of photodissociation cross sections for both parallel and perpendicular orientations of the molecular axis with respect to the field, since previous results existed only for the parallel spectra [2]. An analysis of the two dissociation channels He + H⁺ (measured in the experiment) and He⁺ + H was made. The calculations were performed within the adiabatic approximation, but the importance of the diabatic effects was estimated using the Landau-Zener formula. Since the experimental value is assumed to be obtained from a mixture of initial vibrational states, this aspect is also discussed and cross sections for transitions starting from the vibrational levels ν = 0,1,2,3,4 are shown.

[1] H. B. Pedersen et al., Phys. Rev. Lett. 98, 223202 (2007).

[2] A. Saenz, Phys. Rev. A 67, 033409 (2003).