title: Adsorption of CF4 on graphite preplated with a monolayer of CF3Cl.
abstract: We report a study of the adsorption of CF(4) on graphite preplated with a monolayer of CF(3)Cl, using infrared reflection absorption spectroscopy combined with ellipsometry. The saturated vapor pressure of CF(3)Cl is nearly 3 orders of magnitude smaller than that of CF(4) at the same temperature, so the main control variables are the temperature and the pressure (or chemical potential) of CF(4), together with the initial coverage of CF(3)Cl. The temperature range covered is 60-105 K. We find that, if the initial monolayer of CF(3)Cl is liquid, CF(4) continuously displaces CF(3)Cl by substitution in the monolayer. If the initial monolayer of CF(3)Cl is solid, due to either lower temperature or compression, CF(4) condenses as a second layer on the top of the CF(3)Cl layer, with only slight mixing with the original layer. This behavior persists to multiple layers of CF(4).
authors.affiliation: Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA.
authors.forename: Petros
authors.initials: P
authors.lastname: Thomas
authors.forename: Daniel
authors.initials: D
authors.lastname: Velazquez
authors.forename: George B
authors.initials: GB
authors.lastname: Hess