DECAY DYNAMICS OF H2O(1B1) - FULL CHARACTERIZATION OF OH PRODUCT STATE DISTRIBUTION

H2O was excited to the lowest electronic excited state, 1B1, at 157.6 nm and the OH product state distribution was completely analyzed by special Laser-induced-fluorescence (LIF) experiments probing the fragment distribution by the transitions (v' = 0.1 <-- v"). The OH rotational excitation is relatively low and can be described by a temperature parameter of almost-equal-to 500 K independently of the OH vibrational excitation. This is in accordance with former measurements as well as with theoretical calculations No selective population of the electronic fine-structure levels was observed which is in agreement with the expectations for a room-temperature experiment. The observed magnitude of the vibrational excitation (P(v" = 0): P(v" = 1): P(v" = 2): P(v" = 3): P(v" = 4) = 59.2:33.1:6.1:1.4:0.2) is smaller than the one calculated. The calculations predicted the v" = 6 level to be populated, whereas in the experiment, transitions probing the v" = 5 state were not observed.