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.
Thank you very much
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
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.
Rosa
You have validate the force field by measuring thermodynamic properties (density, melting point, glass trainsition temperature)
Arun
Sorry “estimate thermodynamic properties”
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.