Phases and Phase Transitions in the First Few Layers of Methane, Argon and Krypton Adsorbed on Graphite

摘要: The equilibrium phase diagrams of monolayers many substances adsorbed on graphite have long been studied as examples 2-dimensional (2D) matter. One typically observes 2D gas and liquid phases, solid phases that may be commensurate or incommensurate with the substrate lattice. Many experimental techniques used, but thermodynamic measurements are generally most useful for tracing out boundaries. Recent advances in technique made it possible to use study second higher layers, up fifth sixth. These include ultra high resolution scanning calorimetry, a detailed understanding role capillary condensation corners pores foam substrate. We find rich array transitions multilayer methane, argon krypton. third layers distinct gas, evidenced by triple points critical points. observe between layer below. also melting first at temperatures, even when one five additional top it. In krypton, not strange new phenomenon is observed temperatures above gas-liquid point nth n> 3. Below temperature, nthlayer coexists condensed layer. At some temperature it, coexistence region which partial n + 1st This behavior thought evidence theoretically predicted transition bulk interface, called preroughening transition.