Recent Posts

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1
Input files and parameters / Understanding the Framework option
« Last post by shivanand on June 07, 2019, 12:27:19 PM »
Dear members,

I'm new to RASPA. I want to simulate ice-Ih configuration to compute enthalpy at a given T and P. Can I use Framework option to give the input configuration? I tried it, but the output showed that framework atoms-512 (which i gave) and adsorbate atoms (zero) and crashed after that.

Is the framework option is only for adsorption studies? Is there anyway I can give the .xyz coordinates of ice as an input configuration?

Thanks and regards,
Shivanand
2
Hello all,

How do I add new potential.

I actually want to add steele wall potential for the graphite wall for respective wall-fluid interaction.

Is there any way of adding this potential.

Thanks in advance
3
Simulation algorithms and theory / Potential for Graphite
« Last post by nithin1532 on May 23, 2019, 10:29:46 AM »
Hello all,

Does RASPA use steele wall potential parameters for its graphite structure?
4
Comehere David:

questions are mentioned above, specifically for question 3.
Can i use only LJ parameter, and mass of the atom in mixrule.def and then intense the use of FHLJ .So that the program will calculate the p1p2p3 it self ?

Thanks,
Einstein
5
Input files and parameters / Continuing cycles
« Last post by nithin1532 on May 20, 2019, 07:23:22 AM »
Hello all,

I have a question regarding continuing cycles for MC simulation.

For example:

If I get an output file having an average density with standard deviation of +/- 5 kg/m3 after performing NPT simulation in RASPA with 100000 production and 100000 initial cycles,  will I now be able to perform/continue the simulation again from this output for 50000 (lets assume) more cycles or should I start a fresh simulation with 150000 production and 100000 initial cycles.
6
Input files and parameters / Re: CIF files help
« Last post by Somananda Sanyal on May 16, 2019, 03:00:23 PM »
Hi,

I faced the same problem too, even when I used Material Studio to convert the original .cif file to P1 symmetry.
I have one query, is it necessary to always convert the input structure to P1 symmetry for RASPA or we can also provide the original symmetry?

Thanks in advance!

Warm regards,
Somananda
7
Dear Professor Dubbeldam,

I am trying to do NpT Gibbs Ensemble Monte Carlo simulation instead of NVT Gibbs Ensemble simulation (total volume of the two boxes fixed). For our research problem, we are eventually trying to run the two boxes at different conditions to simulate adsorption process in hopes of following Professor Ilja Siepmann's group's procedure. We hope to run a direct simulation of mixture adsorption.

I could not find an example of running NpT Gibbe Ensemble simulation from the manual, so I proposed that for an NpT Gibbs Ensemble simulation that both boxes are allowed to grow, I can combine NpT ensemble (to utilize the keyword VolumeChangeProbability) with GibbsSwapProbability (imposing chemical equilibrium). The volume change is controlled by the keyword VolumeChangeProbability. Do you agree with such algorithm, or there is a better way to do this type of Gibbs Ensemble?

Following the question above, we want to simulate the case where one box has its volume fixed. Is there a way in Raspa to do this?

Thank you very much for your time and help.

Best,
Kunhuan
8
Input files and parameters / Re: CIF files help
« Last post by petersbk on April 23, 2019, 01:13:06 PM »
Similar to my other post on .cif files, I'll report that I was only able to solve my .cif file problems by using the header from a working P1 .cif file (e.g. from the structures directory in the distribution), cutting out the coordinates, pasting in fractional coordinates for my system of interest, and modifying the cell parameters. I still do not know why some .cif files which work in other codes do not work in raspa, but it mentions somewhere in the manual or other documentation, that they can be tricky.

9
Input files and parameters / Re: Only one Framework atom taken from .cif file
« Last post by petersbk on April 23, 2019, 01:02:41 PM »
In the interest of closure, I'll report that I was only able to solve my .cif file problems by using the header from a working P1 .cif file (e.g. from the structures directory in the distribution), cutting out the coordinates, pasting in fractional coordinates for my system of interest, and modifying the cell parameters. Error messages of the type: "unknown: x" where x is one of the x,y, or z coordinates in the .cif file can occur when something is wrong (not compatible with raspa) with the other lines in the .cif.
10
Simulation algorithms and theory / Anisotropic volume change with Monte Carlo
« Last post by MichaelH on April 18, 2019, 07:31:52 PM »
Dear David,

Im looking at the advanced examples 1 and 2, trying to adapt them to study swelling (in the z-direction) of multi-layered clay(ff) system. Since my clay layers are periodic in x and y, I would like to avoid isotropic volume changes and use some sort of anisotropic-like barostatting instead.

So my question is: When running MonteCarlo, does the volume move (VolumeChangeProbability) only do isotropic volume scaling? or is there some way to activate anisotropic volume trial moves? or simply just do volume moves along the z-direction? I have seen the BoxShapeChangeProbability option, but Im not sure if its effective.

Best regards,

Michael
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