Adsorption of krypton on the basal plane of graphite: LEED and Auger measurements

Adsorbed Solid Xenon and Krypton on Graphite-Diffraction Studies and Model Calculations

“…This parameter has not yet been used to follow the progress of a phase transition, though there are indications that intensities vary during transitions [7] and that the intensities might be used to indicate the microstructure of the layer [16]. Preliminary results are discussed in the next section.…”

Krypton Overlayers on Graphite : Low Energy Electron Diffraction and Auger Electron Spectroscopy Measurements

“…In this paper we present some LEED and Auger determinations of pressures (lo-' torr < p < torr) and temperatures for various two-dimensional phase transitions for Kr on the basal plane of a graphite single crystal. We compare these results with vapor pressure isotherm results [2-41 and earlier LEED and Auger results [7]. In addition we compare the shape of the deregistry transition observed by LEED with that observed by isotherms near 1 torr 121 and present our lattice parameter determination of a two layer film.…”

“…graphite has been extensively studied by isotherm measurements for equilibrium vapor pressures greater than torr [I-61. Adsorption at pressures less than torr was first investigated by Kramer and Suzanne using low-energy electron diffraction (LEED) and Auger spectroscopy [7]. Monolayer condensation was explored by both LEED and Auger measurements, but the transition from an in-registry solid to a compressed, out-of-registry solid first inferred from isotherms at pressures near 1 torr [2] was not observed [7].…”

“…The bulk vapor pressure equation for line (e) is taken from Pollack [14]. A vertical dashed line marks 77 K. [7] and with the extrapolation (line a in Fig. 1) of Larher's measurements [3].…”

Direct Evidence of Abrupt Changes in Two-Dimensional Fluidity in Melting of Monolayers

“…4 * 6,7 Indications of melting in adsorbed films have been deduced from indirect measurements, 8 e.g., studies of vapor pressure, 9 specific heat, 7 * 10 and nuclear resonance. 11 Direct observations of transitions involving positional order have been obtained by electron diffraction 12 and neutron diffraction, 13 but in all these experiments the nature of the transitions was only presumed to involve changes in the mobility and hence they were not conclusively shown to be 2D melting. Here we report measurements of the Debye-Waller factor of monolayer films, giving clear signs of a melting transition, i.e., a change of fluidity in the plane of the film.…”