Force fields in chemistry are equations that approximate the potential energy of atoms and molecules without solving for the electronic degrees of freedom. Simulations using force fields are millions of times faster than ab initio (i.e. quantum mechanical) simulations, enabling the study of large biomolecular systems such as proteins. However, the ability of the force field to predict experiments requires an accurate choice of empirical parameters, which is highly difficult to do in practice. Furthermore, most force fields cannot describe chemical reactions.
The derivation of accurate force field parameters in a systematic and reproducible way has been made possible with the introduction of the ForceBalance method. The video to the left shows a simulation of water freezing into Ice-VI, a high pressure form of ice; the simulation uses the iAMOEBA water model, which was parameterized using ForceBalance (read the paper at http://dx.doi.org/10.1021/jp403802c).
We are currently interested in developing and applying ForceBalance to improve the accuracy of non-covalent interactions and reactive force fields for the purpose of simulating energy conversion mechanisms and protein dynamics.