VUV photodissociation dynamics of diatomic gold, Au2: A velocity map imaging study at 157 nm

The photodissociation dynamics of Au2 at 157 nm have been studied by velocity map imaging. Fragmentation into seven of the nine energetically accessible channels has been observed with a high propensity for the formation of electronically excited fragment atoms. Fragmentation channels are assigned using total energy conservation and confirmed in two-colour experiments in which photolysis is followed by quantum state-selective resonance enhanced multi-photon ionization. The combination of one-and two-colour experiments permits the determination of relative branching ratios at 157 nm for product channels correlating to Au 5d96s2(2D3/2) and Au 5d96s2(2D5/2) atomic fragments.