Düsseldorf 2007 – scientific programme

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SYSX: Symposium Soft X-ray induced ultafast processes on the atomic scale

SYSX 2: Soft X-ray induced ultrafast processes II

SYSX 2.3: Talk

Thursday, March 22, 2007, 17:15–17:30, 6G

VUV FEL photodissociation imaging of HeH⁺ at 32nm — •Simon Altevogt¹, Henrik Pedersen¹, Brandon Jordon-Thaden¹, Oded Heber², Michael Rappaport², Dirk Schwalm¹, Daniel Zajfman², Joachim Ullrich¹, Andreas Wolf¹, Rolf Treusch³, Natalia Guerassimova³, Michael Martins⁴, Jon Hoeft⁴, and Michael Wellhöfer⁴ — ¹Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — ²Department of Particle Physics, Weizman Institute of Science, Rehovot, 76100, Israel — ³HASYLAB, DESY, 22607 Hamburg, Germany — ⁴Institut für Experimentalphysik, Universtität Hamburg, 22671 Hamburg, Germany

Many molecules are most efficiently photofragmented by VUV photons (100 – 30nm). With fast ion beams crossed with an intense photon beam the momentum of neutral fragments after photodinduced reactions can be measured accurately event by event. Such experiments have become possible with the VUV free-electron laser FLASH at DESY. Using the new ion infrastructure TIFF the kinetic energy and angular distributions of neutral He products was measured for HeH⁺ photofragmentation at 32nm together with the absolute cross section for this channel. Excited levels of ¹Π symmetry, not so far considered in photodissociation calculations, are found to dominate the process.