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Welcome to the Force Field X Home Page


Force Field X is an atomic resolution molecular modeling application that targets open research questions in the areas of:

  • predicting the structure, thermodynamic stability and solubility of organic polymer crystals,
  • predicting the effect of missense mutations on protein structure, thermodynamics and molecular phenotype
  • computational design of biomolecules in both soluble and crystalline environments

New Approaches Developed in the Schnieders' Lab

To address these questions, novel global optimization methods and alchemical thermodynamic paths have been implemented in Force Field X. Examples include:

  • Organic crystals property prediction based on "Growth of the Asymmetric Unit into a Crystal via alcHEmy" (GAUCHE)
  • Many-body dead-end elimination (MB-DEE) for global optimization of non-pairwise energy functions over a discrete permutation space (i.e. side-chain rotamers). This algorithm is accelerated across one or more GPUs using MPI and OpenMM.
  • A general "dual force field" framework to compute the thermodynamic cost to change between a fixed charge force field (e.g. OPLS-AA or Amber) and the polarizable multipole AMOEBA force field. This approach has been extended to explore computing the coarsen and refine legs of the indirect free energy path simultaneously (i.e. "Simultaneous Bookending"), which helps the method scale to protein sized systems.
  • Refinement of biomolecular structures against experimental data sets (i.e. X-ray / neutron diffraction and/or CryoEM) and the polarizable AMOEBA force field.


The Force Field X Code and Manual

The FFX code is parallelized for clusters of many-core nodes using an open (GPL v. 3), modular and platform independent approach. See the FFX online manual for instructions on how to download and install the program. The manual also describes available modeling commands and property settings, and provides a few examples with more on the way.

Support for Force Field X

Development of Force Field X has been supported by NSF grants CHE 1404147 and CHE 1751688, and by NIH grants R01 DK110023 and R01 DC012049.