Recent Posts

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General / Using RASPA for Nanocarbons
« Last post by Maxim N. Popov on December 04, 2018, 04:20:45 PM »
Dear Dr. Dubbeldam, dear forum users,

I come from the materials science community, but recently I also got interested in modeling gas adsorption in porous carbons. In an attempt to find the tool to perform GCMC simulations, I came across RASPA. 
Looking at the examples supplied with RASPA2, I got the impression that it is designed with MOFs in mind. Surely, the methodology used in the code is general and can be applied to any porous system. Indeed, there
are a number of publications citing the RASPA paper (https://doi.org/10.1080/08927022.2015.1010082), which deal with carbons.
My question is: could anyone provide me with an example input for GCMC in a carbon-based system (nanotubes, graphene, etc.)?

Best regards,
Maxim N. Popov
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General / Re: GCMC results not exactly matching with literature
« Last post by Vardhan on December 04, 2018, 11:49:26 AM »
Dear Professor,

Thanks for the swift reply. As I have mentioned earlier, the simulation box size (number of unit cells in x y z directions), cutoff-distance, tail corrections, force fields, etc., all were the same. The framework structure was also taken from the same reference.  The only difference I could find is the type of ensemble (Gibbs ensemble vs GCMC). Could this be the reason? Can this have a difference of 0.5mol/Kg?

Thanks and regards
3
General / Re: 'CrashRestart' taking long time
« Last post by David Dubbeldam on December 04, 2018, 10:18:32 AM »
If you know that there is no hysteresis in the system, you could simulate all of these pressure in parallel. That really speeds up computations of isotherms.
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General / Re: GCMC results not exactly matching with literature
« Last post by David Dubbeldam on December 04, 2018, 10:13:39 AM »
That could be for a variety of reasons, including slightly different positions for the atoms of a rigid molecule, and details like cutoff-distance, tail-corrections yes/no, etc. Also, results depend on the total amount of molecules and the system size etc.
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General / GCMC results not exactly matching with literature
« Last post by Vardhan on December 03, 2018, 01:19:18 PM »
Respected Prof. Dubbeldam

I am trying to replicate the adsorption isotherm on a zeolite, from the literature. In the literature, they have used Gibbs ensemble to study the adsorption on a zeolite. Using GCMC in RASPA, I tried to replicate the same thing. However, I am getting lower values compared to the literature. A constant difference of 0.5 mmol/g is being obtained at all pressures (0.1 bar to 10 bar). All the force fields, molecule models, and structure are the same. Could the difference in the ensemble, (or difference in the code) be the reason for this difference of 0.5 mmol/g?

Thanks and regards
6
Input files and parameters / Re: Configuration Files
« Last post by David Dubbeldam on November 26, 2018, 06:54:08 PM »
See e.g. the "Movies yes" and "WriteMoviesEvery 5000" options  (explained in the manual).
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Input files and parameters / Configuration Files
« Last post by arsgk on November 23, 2018, 12:42:33 PM »
Hello everybody

I am new to RASPA and i would like to know how can i have the configuration files (in ASCII format) including the actual coordinates of the atoms (or molecules) for post processing of the simulation. It was not possible for me to write-save the coordinates (and velocities) in a configuration file.

Thank you for your time!
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Input files and parameters / Re: PartionFunction in Reactive Ensemble
« Last post by Junran Lu on November 13, 2018, 03:59:12 AM »
Prof. Dubbeldam,

Thank you very much for the answer.  :)
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Input files and parameters / Re: PartionFunction in Reactive Ensemble
« Last post by David Dubbeldam on November 12, 2018, 11:45:46 AM »
In the literature and articles on "Reactive ensemble" the authors usually cite articles that describe how to compute these (either using QM calculations or using experimental date tables).
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Input files and parameters / Re: Error while using "Grid" option
« Last post by David Dubbeldam on November 12, 2018, 11:42:57 AM »
You can select which atoms to use for interpolation. The other ones will be computed in the usual way without interpolation.
The test at the beginning is limited and just meant to catch obvious wrong interpolations. But it is up to the user to judge whether the interpolation is sufficiently accurate or not. A few test of e.g. isotherms with and without grids can shows whether the grid is accurate enough.
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