LIF IMAGING APPLIED TO THE PHOTODISSOCIATION OF POLYATOMIC-MOLECULES

The Photodissociation of HNO3 at 193 nm and of NO2 at 308 nm in a nozz le beam is used to test the potential of LIF imaging techniques for th e state selective detection of angular and velocity distributions of t he photofragments NO and OH. The dissociation laser and the probe lase r are spatially delayed to probe the products away from the dissociati on laser beam. For S/N reasons these first experiments are carried out downstream from the nozzle so close to the exit (15 mm) that collisio n-free conditions are only valid for a short time. Therefore the exper iments yield correct state-resolved TOF distributions only for the fas test fragments. Some indications for correlated product formation are found in the case of HN03 Photodissociation. Although the S/N ratio is poor, several possible improvements indicate that the method is promi sing for a detailed analysis of correlated product formation in the ph otodissociation of polyatomic molecules.