Mobility measurements of two kinds of two-dimensional fluids. Methane adsorbed on graphite
نویسندگان
چکیده
2014 The diffusion coefficient of a CH4 submonolayer adsorbed on (0001) graphite is measured as a function of coverage and temperature by quasi-elastic neutron scattering. The experimental data permit us to clearly distinguish two kinds of adsorbed fluids, i.e. a 2D liquid coexisting with a 2D gas and a 2D hypercritical fluid whose density varies continuously with coverage. The mobility disappears at solidification which can be obtained either by decreasing temperature at constant coverage or by increasing coverage at constant temperature. The coexistence of 2D solid and 2D liquid is also observed. Finally a phase diagram of the first layer of methane adsorbed on graphite is proposed. J. Physique 42 (1981) 293-306 FÉVRIER 1981,
منابع مشابه
Quasi-Two-Dimensional Phase Transition of Methane Adsorbed in Cylindrical Silica Mesopores.
Using Monte Carlo and molecular dynamics simulations, we examine the adsorption of methane in cylindrical silica mesopores in an effort to understand a possible phase transition of adsorbed methane in MCM-41 and SBA-15 silica that was previously identified by an unexpected increase in the adsorbed fluid density following capillary condensation, as measured by small-angle neutron scattering (SAN...
متن کاملA first order two-dimensional melting transition : methane adsorbed on (0001) graphite
2014 The variation of long range order of a registered solid submonolayer of methane adsorbed on the graphite basal plane is measured at melting by neutron elastic scattering. The sudden loss of order indicates a first order melting transition and defines the two-dimensional triple point of the layer, namely 56 ± 0.4 K. LE JOURNAL DE PHYSIQUE LETTRES TOME 40, 15 OCTOBRE 1979, Classification Phy...
متن کاملThree-dimensional numerical simulation of temperature and flow fields in a Czochralski growth of germanium
For a Czochralski growth of Ge crystal, thermal fields have been analysed numerically using the three-dimensional finite volume method (FLUENT package). The arrangement used in a real Czochralski crystal growth lab included a graphite crucible, heat shield, heating device, thermal insulation and chamber including two gas outlets. We have considered two cases for calculations, which are configur...
متن کاملIncomplete wetting of methane on graphite at low temperatures
The wetting behaviour of methane on graphite has been studied by means of low energy electron diffraction and reflection high energy electron diffraction in the temperature range 14-40 K. Incomplete wetting, or crystallite formation, is detected over the entire temperature range for films with thicknesses of 15 or more layers. Isosteric heats of adsorption are reported for the 2nd, 3rd and 4th ...
متن کاملPredicting adsorption isotherms using a two-dimensional statistical associating fluid theory.
A molecular thermodynamics approach is developed in order to describe the adsorption of fluids on solid surfaces. The new theory is based on the statistical associating fluid theory for potentials of variable range [A. Gil-Villegas et al., J. Chem. Phys. 106, 4168 (1997)] and uses a quasi-two-dimensional approximation to describe the properties of adsorbed fluids. The theory is tested against G...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2016