Surface self-diffusion at intermediate temperature: The Ag(110) case

Energy-resolved He atom scattering is adopted to investigate self-diffusion on Ag(110) in a temperature range well below the bulk melting point. Information on the mobility of adsorbed silver atoms between room temperature and 800 K is gained along the <1 (1) over bar0> and <001> azimuthal directions measuring the evolution of the quasielastic peak broadening with parallel momentum transfer at different temperatures. The diffusion coefficients are estimated and strong anisotropy is evidenced by adsorbed atoms moving mainly along the <1 (1) over bar0> surface rows. Along this azimuth the main diffusion mechanism is pointed out and an estimation of the effective diffusion barrier is given. The results are compared with the predictions of molecular-dynamics calculations.