On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface
© 2015 Elsevier Inc. The adsorption and desorption of Kr on graphite at temperatures in the range 60-88. 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 Sc...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Academic Press Inc.
2015
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| Online Access: | http://hdl.handle.net/20.500.11937/35982 |
| _version_ | 1848754643465666560 |
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| author | Diao, R. Fan, Chunyan Do, D. Nicholson, D. |
| author_facet | Diao, R. Fan, Chunyan Do, D. Nicholson, D. |
| author_sort | Diao, R. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | © 2015 Elsevier Inc. The adsorption and desorption of Kr on graphite at temperatures in the range 60-88. 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-solid-like 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 recognised 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 co-existence 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. |
| first_indexed | 2025-11-14T08:43:40Z |
| format | Journal Article |
| id | curtin-20.500.11937-35982 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:43:40Z |
| publishDate | 2015 |
| publisher | Academic Press Inc. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-359822018-03-29T09:09:14Z On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface Diao, R. Fan, Chunyan Do, D. Nicholson, D. © 2015 Elsevier Inc. The adsorption and desorption of Kr on graphite at temperatures in the range 60-88. 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-solid-like 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 recognised 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 co-existence 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. 2015 Journal Article http://hdl.handle.net/20.500.11937/35982 10.1016/j.jcis.2015.08.072 Academic Press Inc. restricted |
| spellingShingle | Diao, R. Fan, Chunyan Do, D. Nicholson, D. On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title | On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title_full | On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title_fullStr | On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title_full_unstemmed | On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title_short | On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface |
| title_sort | on the 2d-transition, hysteresis and thermodynamic equilibrium of kr adsorption on a graphite surface |
| url | http://hdl.handle.net/20.500.11937/35982 |