Hannover 2010 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 8: Poster: Electronic Spectroscopy
MO 8.7: Poster
Dienstag, 9. März 2010, 16:00–18:30, Lichthof
Proton formation in [2+1]-REMPI of HCl: A 3D Velocity Mapping study — S. Kauczok, •C. Maul, and K.-H. Gericke — Institut für Physikalische und Theoretische Chemie, TU Braunschweig
HCl was excited via Q lines of the two-photon transitions F1Δ2←X1Σ+ (1,0), V1Σ+←X1Σ+ (14,0) and f3Δ2←X1Σ+ (0,0). Spatial proton velocity distributions produced in subsequent one-photon processes were studied by 3D velocity mapping.[1]
Increased H+ and Cl− ion formation in some F←X and f←X rovibrational transitions was reported and explained by the vicinity of rovibrational levels of the V1Σ+ state.[2] Thus, the known V1Σ+ dissociation dynamics should also leave a fingerprint in the proton velocity distribution emerging from the photodissociation of those states.
For the f←X transition, we found that for the near resonant Q(5) line the HCl+(v≥5) photodissociation channel is effectively switched off and that the Cl spin-orbit state changes from 2P3/2 to 2P1/2 while off-resonant excitation results in 1) autoionization to HCl+(5≤v+≤8) and 2) non-adiabatic dissociation into H(n=2)+Cl(2P3/2).
The F←X band showed significant proton formation for Q(8) only with a speed distribution similar to V←X Q(8) while in the angular distribution the excitation history is conserved.
[1] A. Chichinin, S. Kauczok, K.-H. Gericke, C. Maul, Int. Rev. Phys. Chem., 28, 607 (2009)
[2] A. Kvaran, H. Wang, K. Matthiasson, A. Bodi, E. Jonsson, J. Chem. Phys., 129, 164313 (2008), A. Kvaran, K. Matthiasson, H. Wang, J. Chem. Phys., 131, 044324 (2009)