Real-time observation of the diffusive motion of 2 x 2 adlayer formed on Ag(100) nanoparticle facet by nitric acid adsorption

The 2 x 2 adlayer formed on a (100) facet of a Ag nanoparticle by the adsor ption of nitric acid has been investigated by high-resolution electron micr oscopy in the profile imaging mode. The adsorbates showed a profile image t hat is double-periodical to that of Ag(100) surface along the [010] directi on, and their collective diffusion was observed in real time. From the expe rimental facts along with the multi-slice image simulation results, it is r easonable to conclude that the observed adlayer was coming from a c(2 x 2) structure of nitrates adsorbed on a long-bridge site of Ag(100).