Photodesorption of O2 from Ag2 -: A time-resolved study of Ag2O2 - A

Abstract

We present time-resolved photoelectron spectra of mass-selected Ag 2O2 anions. The anions are photoexcited by photons with an energy of 3.1 eV, and photoelectron spectra of the excited species Ag 2O2 - * and the subsequently appearing fragments are recorded using a probe laser pulse with a photon energy of 1.5 eV. The excited state of Ag2O2 - has a short lifetime of 130 fs±70 fs only and decays by direct photodesorption of O2. The data demonstrate the ability of time-resolved photoelectron spectroscopy (TR-PES) to observe the breaking of chemical bonds if the decay process of the excited state is direct (non-thermal desorption). The data are compared to recent results of a NeNePo experiment [1] on the same system. © Springer-Verlag 2007.