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Re: [lammps-users] Problems with compass parameters
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Re: [lammps-users] Problems with compass parameters


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Tue, 1 Aug 2017 12:29:14 -0400



On Tue, Aug 1, 2017 at 10:59 AM, Rosa Osorio <gisepava@...8...> wrote:
Dear lammps users

Looking for parameters to develop simulation on furano, tiofeno and piridina with COMPASS force field, i found a force field named pcff. The COMPASS force field usually fits well, but does not have many parameters.  According to the literature pcff is a previous version of COMPASS. So do you know if is possible to take pcff Lennard-Jones parameters and replace it over the nonexistent COMPASS parameters. I mean is right to join pcff and COMPASS parameters on a same molecule? Thanks for your time.

​mixing force fields is rarely a good idea, even if they share a common ancestry. during the process of deriving the parameters, certain assumptions are made and specific strategies are employed to derive parameters in a consistent fashion. by mix- and matching parameters, you lose that consistency, which in turn would the validity of your entire simulation in question. in this case it means, that it would be more consistent to stick with PCFF for everything.

axel.

 
Rosa
De: Axel Kohlmeyer <akohlmey@...24...>
Enviado: jueves, 27 de julio de 2017 5:32:04 p. m.
Para: Rosa Osorio
Cc: LAMMPS Users Mailing List
Asunto: Re: [lammps-users] Problems with compass parameters
 


On Jul 27, 2017 17:56, "Rosa Osorio" <gisepava@...8...> wrote:

Dear lammps users


I'm building different liquid solvents using the COMPASS force field with the lammps / tools / msi2lmp / compass_published.frc folder. However, the lammps library does not have the LJ parameters of many molecules. I would like to know the LJ parameters of oxygen, sulfur and nitrogen in furan, thiophene and pyridine respectively.


LAMMPS can only bundle compass force field parameters described in scientific publications. Many others are only available under a commercial license from biovia (formerly accelrys). 

Axel


Thank you very much


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--
Dr. Axel Kohlmeyer  akohlmey@...12...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.