Photodissociation dynamics of water in K-edge energy region

Gejo, Tatsuo*; Kuniwake, Miki*; Homma, Kenji*; Harries, J.; Oura, Masaki*; Sullivan, J. P.*; Azuma, Yoshiro*

Exciting an inner-shell electron of a molecule to just-above or just-below its ionisation limit provides a system where the Born-Oppenheimer principle is no longer valid, and a valuable opportunity for studying the interaction of the unstable ion core and a low-energy electron. When the ion core undergoes Auger decay and fragments, the initially excited electron can be recaptured. It is the aim of this research to understand what happens in the case of the water molecule, by (1) detecting excited H atoms produced when the electron is captured by an outgoing proton. (2) detect the Lyman- radiation produced when these excited H atoms decay, and (3) analysing the energy of low-energy Auger electrons emitted when the electron is captured by an O or O fragment.