Adatom formation mechanism on Ag(110) studied by quasielastic He atom scattering

The temperature dependence of the diffuse elastic peak is measured using helium atom scattering on Ag(110) along the (110) azimuth. A previous study performed by our group [Phys. Rev. B 66, 45 414 (2002)] demonstrates that this scattering contribution may be ascribed to silver atoms adsorbed on the flat (110) terraces. To obtain information on the adatom creation process the evolution of the peak intensity is analyzed following the method proposed by Silvestri, Graham, and Toennies [Phys. Rev. Lett. 81, 1034 (1998)]. In the case of Ag(110) this method has to be modified to take into account the anharmonic contributions to the surface lattice vibrations. The energy for adatom formation is determined to be E a =(0.38′0.03) eV. This estimate is compared with the predictions of molecular-dynamics simulations suggesting that adatoms are mainly released from flat terraces and/or from (110) oriented step edges.