Eur. Phys. J. D 53, 59-62 (2009)
https://doi.org/10.1140/epjd/e2009-00059-y

O₂ photodesorption from a Ag₈O₂^- cluster

Department of Physics, University of Konstanz, 78457 Konstanz, Germany

Corresponding author: ^a gerd.gantefoer@uni-konstanz.de

Received: 31 October 2008
Revised: 12 January 2009
Published online: 18 February 2009

Abstract

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.