The binding energy of noble gases depends on the arrangement of atoms close to the adatom. Due to the weak forces of physisorption a rearrangement of the substrate during adsorption is unlikely. Therefore, the desorption of noble gases reveals the local arrangement of surface atoms. It is demonstrated that the structures of the Si(111) surface produced by adsorption of gases or metal overlayers have besides the well-known long range order quite different desorption spectra which point to specific short range order or local atom arrangements. © 1985, American Vacuum Society. All rights reserved.