O2 photodesorption from a Ag8O2- cluster
Department of Physics, University of Konstanz, 78457 Konstanz, Germany
Corresponding author: a email@example.com
Revised: 12 January 2009
Published online: 18 February 2009
The decay path of an Ag8(O2)- cluster photoexcited by a 3.1 eV photon is elucidated using time-resolved photoelectron spectroscopy. Photoabsorption results in the formation of an excited state giving rise to a peak in the photoelectron spectra with well-resolved vibrational finestructure. With a lifetime of about 100 fs this bound state decays into an anti-bonding state which dissociates into O2 and Ag8- on a timescale of 10 ps. In the photoelectron spectra, this corresponds to a broad maximum shifting gradually towards higher binding energy while the O2 and Ag8- separate. Finally, the spectrum of bare Ag8- appears. This process is unique to small clusters, because on metal surfaces excited state lifetimes are too short to allow for direct dissociation.
PACS: 68.43.Tj – Photon stimulated desorption / 78.47.J- – Ultrafast pump/probe spectroscopy / 33.80.Eh – Autoionization, photoionization, and photodetachment / 36.40.-c – Atomic and molecular clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009