open force field

An open and collaborative approach to better force fields


Semantic versioning of force fields follows MAJOR(x).MINOR(y).PATCH scheme and new versions will be released as openff-x.y.z:

x : functional form change and/or major scientific update

y : parameter refit epoch

z : bugfix / hotfix

Generally, major increments MAY indicate a functional form or compatibility change, but don't NEED to. However, if compatibility DOES change, then major version number MUST increment.


Force field versions with major updates will be referred to as generations , not releases, for clearer communication purposes. Each new force field generation will have a specific codename associated with it, while the minor and patch releases will be captured in openff-x.y.z version names. The codenames will be given after herbs.

Biomolecular force fields:

amber14sb will be ported to amber14SB.offxml. After the first refit, biomolecular force field parameters will become a part of openff-x.y.z with documentation describing the details.