Tunable VUV photochemistry using Rydberg H-atom time-of-flight spectroscopy.

In this article, we report an experimental method for studying tunable vacuum ultraviolet (VUV) photochemistry using the H-atom Rydberg tagging technique. In this method, two VUV laser light beams were generated using nonlinear four-wave mixing scheme in a single Kr gas cell: one VUV beam is fixed at the 121.6 nm wavelength to probe the H-atom product through the Lyman alpha transition, the other beam can be tunable for photodissociating molecules in the wavelength range lambda(VUV)=121-190 nm. Preliminary results on the H(2)O photodissociation in the B state are reported here. These results suggest that the experimental method is a powerful tool for investigating photodissociation dynamics in the VUV region for molecules involving H-atom processes.