Sublimative desorption of xenon from Ru(100)

Abstract

Sublimative desorption is a process in which desorption of multilayers of an adsorbate precedes melting and surface diffusion. Here we report on the desorption kinetics of Xe atoms from multilayer coverage studied using temperature programmed desorption and optical diffraction methods. It is found that decay of the diffraction peak intensities from multilayer coverage grating during surface heating cannot be explained as one-dimensional diffusion process. Instead, the diffraction signal follows Xe desorption, as deduced from simultaneous linear diffraction and desorption measurements. This observation suggests that no macroscopic two-dimensional melting and diffusion occur in the case of multilayers of Xe before the onset for desorption. It is concluded that Xe atoms undergo sublimative desorption from the topmost layers. Similar results were obtained in the case of water multilayers on Rus100d. These results suggest that on solid surfaces the desorption of multilayers is thermodynamically favorable over surface melting or diffusion.