Annoucement: The COMPASS force field can now be used with
moltemplate to prepare LAMMPS simulations. Several examples using
this force field are available:
Only the subset of the atom types from the COMPASS force field
which have been disclosed publicly are included. (This is similar to
the restrictions placed on other molecule-builders that support
COMPASS such as EMC, TOWHEE, or msi2lmp.)
Thanks to Marcus Martin for patiently answering long, complex
emails to help me interpret the contents of these MSI files.
Thanks to Paul Sax at Materials Design Inc for collecting these
force field parameters and posting them.
The "compass.lt" file used by moltemplate was created by applying a
script ("msifrc2lt.py") to the "compass_published.frc" file posted by
Paul Sax and distributed with LAMMPS. If you manage to obtain a
complete version of the "compass.frc" file which is unencrypted, you
should be able to use it with "msifrc2lt.py" (and moltemplate) as
The current version of this force field uses "hybrid" force-field
styles, which unfortunately makes it incompatible with KOKKOS. A
future update will fix this issue.
As of 2018-6-17, other MSI force fields (such as PCFF and CVFF) are
more complicated and are not yet compatible with "msifrc2lt.py" or
moltemplate. As with COMPASS, the publicly available portion of these
force fields are missing a large number of atom types and parameters
as well. Unless there is a legal way to obtain these missing
parameters, I will postpone work on converting these other force
Hope this is useful.
You must download the most recent version of moltemplate from
moltemplate.org (or https://github.com/jewettaij/moltemplate) in order
to use the COMPASS force field. The version of moltemplate currently
distributed with LAMMPS is not up to date.