LIF IMAGING APPLIED TO THE PHOTODISSOCIATION OF POLYATOMIC-MOLECULES

The Photodissociation of HNO3 at 193 nm and of NO2 at 308 nm in a nozzle beam is used to test the potential of LIF imaging techniques for the state selective detection of angular and velocity distributions of the photofragments NO and OH. The dissociation laser and the probe laser are spatially delayed to probe the products away from the dissociation laser beam. For S/N reasons these first experiments are carried out downstream from the nozzle so close to the exit (15 mm) that collision-free conditions are only valid for a short time. Therefore the experiments yield correct state-resolved TOF distributions only for the fastest 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 promising for a detailed analysis of correlated product formation in the photodissociation of polyatomic molecules.