On the existence of a hysteresis loop in open and closed end pores
We have studied the adsorption of argon at 87 K in slit pores of finite length with a smooth graphitic potential, open at both ends or closed at one end. Simulations were carried out using conventional GCMC (grand canonical Monte Carlo) or kMC (kinetic Monte Carlo) in the canonical ensemble with ext...
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| Format: | Journal Article |
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Taylor & Francis Ltd
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/7411 |
| _version_ | 1848745360494690304 |
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| author | Fan, Chunyan Do, D. Nicholson, D. |
| author_facet | Fan, Chunyan Do, D. Nicholson, D. |
| author_sort | Fan, Chunyan |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We have studied the adsorption of argon at 87 K in slit pores of finite length with a smooth graphitic potential, open at both ends or closed at one end. Simulations were carried out using conventional GCMC (grand canonical Monte Carlo) or kMC (kinetic Monte Carlo) in the canonical ensemble with extremely long Markov chain, of at least 2 × 108 configurations; selected simulations with much longer Markov chains do not show any change in the results. When the pore width is in the micropore range (0.65 nm), type I isotherms are obtained for both pore models and for both simulation methods. However, wider pores (1, 2 and 3 nm in width) all exhibit hysteresis loops in the GCMC simulations, while in the canonical ensemble simulations, the isotherms pass through a sigmoid van der Waals type loop in the transition region. This loop locates the true equilibrium transition. For the pores with one closed end, this transition is close to, or coincides with, the adsorption branch of the GCMC hysteresis loop, but for the open-ended pores, it is more closely associated with the desorption branch. In a separate study of adsorption hysteresis in an infinitely long slit pore, using both simulation techniques, the van der Waals loop follows the adsorption branch of the GCMC isotherm to the transition, then reverts to a long vertical section that falls midway between the two hysteresis branches and finally moves to the desorption transition close to the evaporation pressure. An examination of molecular distributions inside the pores reveals two coexisting phases in the canonical simulations, whereas in the grand canonical simulations, the molecules are uniformly distributed along the length of the pores. |
| first_indexed | 2025-11-14T06:16:07Z |
| format | Journal Article |
| id | curtin-20.500.11937-7411 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:16:07Z |
| publishDate | 2014 |
| publisher | Taylor & Francis Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-74112017-09-13T14:37:53Z On the existence of a hysteresis loop in open and closed end pores Fan, Chunyan Do, D. Nicholson, D. Monte Carlo simulation hysteresis closed end pore adsorption slit pore We have studied the adsorption of argon at 87 K in slit pores of finite length with a smooth graphitic potential, open at both ends or closed at one end. Simulations were carried out using conventional GCMC (grand canonical Monte Carlo) or kMC (kinetic Monte Carlo) in the canonical ensemble with extremely long Markov chain, of at least 2 × 108 configurations; selected simulations with much longer Markov chains do not show any change in the results. When the pore width is in the micropore range (0.65 nm), type I isotherms are obtained for both pore models and for both simulation methods. However, wider pores (1, 2 and 3 nm in width) all exhibit hysteresis loops in the GCMC simulations, while in the canonical ensemble simulations, the isotherms pass through a sigmoid van der Waals type loop in the transition region. This loop locates the true equilibrium transition. For the pores with one closed end, this transition is close to, or coincides with, the adsorption branch of the GCMC hysteresis loop, but for the open-ended pores, it is more closely associated with the desorption branch. In a separate study of adsorption hysteresis in an infinitely long slit pore, using both simulation techniques, the van der Waals loop follows the adsorption branch of the GCMC isotherm to the transition, then reverts to a long vertical section that falls midway between the two hysteresis branches and finally moves to the desorption transition close to the evaporation pressure. An examination of molecular distributions inside the pores reveals two coexisting phases in the canonical simulations, whereas in the grand canonical simulations, the molecules are uniformly distributed along the length of the pores. 2014 Journal Article http://hdl.handle.net/20.500.11937/7411 10.1080/08927022.2013.869805 Taylor & Francis Ltd restricted |
| spellingShingle | Monte Carlo simulation hysteresis closed end pore adsorption slit pore Fan, Chunyan Do, D. Nicholson, D. On the existence of a hysteresis loop in open and closed end pores |
| title | On the existence of a hysteresis loop in open and closed end pores |
| title_full | On the existence of a hysteresis loop in open and closed end pores |
| title_fullStr | On the existence of a hysteresis loop in open and closed end pores |
| title_full_unstemmed | On the existence of a hysteresis loop in open and closed end pores |
| title_short | On the existence of a hysteresis loop in open and closed end pores |
| title_sort | on the existence of a hysteresis loop in open and closed end pores |
| topic | Monte Carlo simulation hysteresis closed end pore adsorption slit pore |
| url | http://hdl.handle.net/20.500.11937/7411 |