Darmstadt 2008 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 19: Photochemie
MO 19.1: Poster
Donnerstag, 13. März 2008, 16:30–19:00, Poster C1
3D Velocity Mapping: Dynamics of the reaction O(1D) + N2O → 2NO photoinitiated in the (N2O)2 dimer — Niels Goedecke1, Sebastian Kauczok1, •Christof Maul1, Alexey Chichinin1,2, and Karl-Heinz Gericke1 — 1Institut für Physikalische und Theoretische Chemie, TU Braunschweig — 2Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk
3D velocity mapping allows state specific characterization of full three dimensional velocity distributions of reaction products following resonance-enhanced multi-photon ionization (REMPI). 3D resolution is achieved by using a time-of-flight (TOF) spectrometer equipped with a two-dimensional delay line behind a micro channel plate stack which simultaneously returns impact position and time of the selected reaction product. Inserting an Einzel lens into the TOF spectrometer allows to map the product velocity and to get rid of image distortion due to the unavoidable length of the ionization laser focus.
The technique has been used to investigate the reaction of O(1D) with N2O in the (N2O)2 dimer. O(1D) is generated by photodissociation of N2O using an ArF excimer laser. The reaction yields two NO molecules which are subsequently ionized via a (1+1)-REMPI process by a dye laser. We have measured selected quantum state specific 3D velocity distributions of the NO product as well as spectra for several vibrational states (v ≤ 7) of the electronic ground state X(2ΠΩ). The rotational temperature is low, in agreement with earlier investigations of the cluster reaction, but in striking contrast to the free collision.