Summary: Local Investigation of Femtosecond Laser Induced Dynamics of Water Nanoclusters on Cu(111)
and Karina Morgenstern1
Institut fu¨r Festko¨rperphysik, Leibniz Universita¨t Hannover, Appelstraße 2, 30167 Hannover, Germany
London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1E 6BT, United Kingdom
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
(Received 17 February 2009; published 10 July 2009)
We explore the dynamics of low temperature interfacial water nanoclusters on Cu(111) by
femtosecond-laser excitation, scanning tunneling microscopy and density functional theory. Laser
illumination is used to induce single molecules to diffuse within water clusters and across the surface,
breaking and reforming hydrogen bonds. A linear diffusion probability with laser fluence is observed up to
0:6 J=m2 and we suggest that diffusion is initiated by hot electron attachment and detachment processes.
The density functional calculations shed light on the detailed molecular mechanism for water diffusion
that is determined by the local structure of the water clusters.
DOI: 10.1103/PhysRevLett.103.026101 PACS numbers: 68.37.Ef, 68.43.Bc, 82.30.Rs, 82.53.St