Adsorption de molécules simples sur graphite

Thomy, A.; Duval, Xavier

doi:10.1051/jcp/1970671101

Cited by 373 publications

(111 citation statements)

References 0 publications

Supporting

Mentioning

101

Contrasting

Unclassified

Order By: Relevance

“…Subsequently these transitions were observed experimentally by many other researchers [2-4, 8, 21, 26]. In addition to the layer-by-layer character of the krypton isotherm on a homogeneous graphite surface, small sub-steps are observed in the first layer [6,9,10,19,26], suggesting some ordering of adsorbed molecules. The physical processes associated with the steps and sub-steps depend critically on the adsorption temperature:…”

Section: Introductionmentioning

confidence: 52%

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

Diao

Fan

et al. 2015

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

The adsorption and desorption of Kr on graphite at temperatures in the range 60 K to 88 K, was systematically investigated using a combination of several simulation techniques including: grand canonical Monte Carlo (GCMC), canonical kinetic-Monte Carlo (C-kMC) and the Mid-Density scheme (MDS). Particular emphasis was placed on the gas-solid, gas-liquid and liquid-solid 2D phase transitions. For temperatures below the bulk triple point, the transition from a 2D-liquid-like monolayer to a 2D-solid-like state is manifested as a sub-step in the isotherm. A further increase in the chemical potential leads to another rearrangement of the 2D-solidlike state from a disordered structure to an ordered structure that is signalled by (1) another sub-step in the monolayer region and (2) a spike in the plot of the isosteric heat versus density at loadings close to the dense monolayer coverage concentration. Whenever a 2D transition occurs in a grand canonical isotherm it is always associated with a hysteresis, a feature that is not widely recognized in the literature. We studied in details this hysteresis with the analysis of the canonical isotherm, obtained with C-kMC, which exhibits a van der Waals (vdW) type loop with a vertical segment in the middle. We complemented the hysteresis loop and the vdW curve with the analysis of the equilibrium transition obtained with the MDS, and found that the equilibrium transition coincides exactly with the vertical segment of the C-kMC isotherm, indicating the coexistence of two phases at equilibrium. We also analysed adsorption at higher layers and found that the 2D-coexistence is also observed, provided that the temperature is well below the triple point. Finally the 2D-critical temperatures were obtained for the first three layers and they are in good agreement with the experimental data in the literature.

show abstract

Section: Introductionmentioning

confidence: 52%

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

Diao

Fan

et al. 2015

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

show abstract

“…Previous reports have linked the preadsorbate's wetting properties to displacement [6,10,11]. Unlike Kr and CH 4 , which exhibit layer by layer growth into thick films on graphite [12], the preadsorbates discussed here, CCl 4 , C 6 H 12 , and SF 6 , do not fully wet graphite at the temperatures where displacement is observed [1,3,13]; instead, a full monolayer film coexists with its own bulk crystals. Such coexistence implies that CCl 4 , for example, can be moved from film to bulk phase without a change in free energy, provided it does not leave an empty space behind.…”

Section: (Received 3 May 1999)mentioning

confidence: 58%

Theory and Observation of Displacement Phenomena in Coadsorbed Films

Weber

Goodstein

1999

Phys. Rev. Lett.

View full text Add to dashboard Cite

Displacement refers to a surprising phenomenon observed in a number of adsorption systems. At low temperatures, some relatively inert gases, such as krypton (Kr) or methane (CH 4 ), are found to displace molecules from preadsorbed monolayer films of a more condensable species, such as carbon tetrachloride (CCl 4 ), from a graphite substrate. We present a simple thermodynamic model to explain displacement and make a prediction applicable to both first-order and continuous displacement processes. We also present measurements on CH 4 ͞CCl 4 and Kr͞CCl 4 coadsorbed films from 77 -112 K that verify our prediction and yield the CCl 4 film spreading pressure.

show abstract

“…Low pressure experiments of krypton adsorption on exfoliated graphite and graphitized carbon black indicated a behavior characteristic of 2D fluids. 3,4 In comparison to the research of 3D [5][6][7][8][9] fluids, 1D 10 and 2D fluids have attracted much less attention. Low dimensional systems have in addition to their interest as simple models for real situations, also important to understand the effect of dimensionality on phase transitions.…”

Section: Introductionmentioning

confidence: 99%

Properties of the two-dimensional heterogeneous Lennard-Jones dimers: An integral equation study

Urbič

2016

The Journal of Chemical Physics

View full text Add to dashboard Cite

Structural and thermodynamic properties of a planar heterogeneous soft dumbbell fluid are examined using Monte Carlo simulations and integral equation theory. Lennard-Jones particles of different sizes are the building blocks of the dimers. The site-site integral equation theory in two dimensions is used to calculate the site-site radial distribution functions and the thermodynamic properties. Obtained results are compared to Monte Carlo simulation data. The critical parameters for selected types of dimers were also estimated and the influence of the Lennard-Jones parameters was studied. We have also tested the correctness of the site-site integral equation theory using different closures. Published by AIP Publishing. [http://dx

show abstract

Adsorption de molécules simples sur graphite

Cited by 373 publications

References 0 publications

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

Theory and Observation of Displacement Phenomena in Coadsorbed Films

Properties of the two-dimensional heterogeneous Lennard-Jones dimers: An integral equation study

Contact Info

Product

Resources

About