Transient photoelectron spectroscopy of the dissociative Br2(1IIu) state

Photodissociation of bromine on the Br-2((1)Pi(u)) state is probed with ultrafast extreme ultraviolet (53.7 nm) single-photon ionization. Time-resolved photoelectron spectra show simultaneously the depletion of ground state bromine molecules as well as the rise of Br(P-2(3/2)) products due to 402.5 nm photolysis. A partial photoionization cross-section ratio of atomic versus molecular bromine is obtained. Transient photoelectron spectra of a dissociative wave packet on the excited state are presented in the limit of low-power-density, single-photon excitation to the dissociative state. Transient binding energy shifts of atomic-like photoelectron peaks are observed and interpreted as photoionization of nearly separated Br atom pairs on the Br-2((1)Pi(u)) state to repulsive dissociative ionization states. (c) 2007 American Institute of Physics.