Laser ionisation detection of O(3Pj) atoms in the VUV; application to photodissociation of O2

Detection of O(3Pj) atoms using one-photon resonant excitation to the 3s3S1o state at ?130 nm followed by near-threshold ionisation, i.e. 1 + 1' resonance-enhanced multi-photon has been investigated. The aim was achieve low ion recoil, improved sensitivity, and reliable angular momentum polarisation information, with an as simple possible laser setup. An efficient scheme found where VUV light for first step is generated difference frequency (2?1??2) generation, ionisation uses 2?2 around 289 nm. presented induces 9 m/s recoil O+ a two-dye system, zero should be generating 302 radiation third dye laser. While this approach much more sensitive than previous 212.6 step, we that relatively intense beam does not saturate step. To test ability accurately determine branching ratios, fine structure yields, distributions including it applied O2 photodissociation 130 subsequent fragment detection.