3D Velocity Map Imaging: Instrument Design and Application to Quantum State Selective Reaction Dynamics

The book has been written as a dissertation on the University of Braunschweig, Germany under supervision of Prof. Dr. Karl-Heinz Gericke. It deals with the development, description and application of a three dimensional velocity map imaging technique for products of elementary chemical reactions such as photodissociations and reactive collisions. By means of REMPI spectroscopy the quantum state of the products is also resolved. In contrast to earlier reports of 3D velocity mapping techniques that were based on 2D velocity map imaging and the specific time of flight spectrometer used for this, the technique presented is an enhancement of 3D ion imaging and its one field spectrometer. As a result, the time broadening due to the kinetic energy release and therefore the resolution in the third dimension is much larger than for the techniques reported earlier having a rather poor time resolution despite comparable detector features. The processes studied comprise: i)The reactive collision dynamics of O(1D) with D2 as a proof for a novel technique to study photoinitiated bimolecular reactions being a hybrid of the PHOTOLOC technique and the parallel beams technique used by the groups of Kitsopoulos, Orr-Ewing and Suits. ii) The photodissociation dynamics of the B1Σ+ double minimum state of HCl accessed by two-photon absorption. iii) The dynamics of the constrained geometry reaction of O(1D) and N2O inside the(N2O)2 dimer.