Improvements to the AMOEBA Force Field by Introducing Anisotropic Atomic Polarizability of the Water Molecule.
Akshaya K DasOmar N DemerdashTeresa Head-GordonPublished in: Journal of chemical theory and computation (2018)
In this work, we have developed an anisotropic polarizable model for the AMOEBA force field that is derived from electrostatic fitting on a gas phase water molecule as the primary approach to improve the many-body polarization model. We validate our approach using small to large water cluster benchmark data sets and ambient liquid water properties and through comparisons to a variational energy decomposition analysis breakdown of molecular interactions for water and water-ion trimer systems. We find that the accounting of anisotropy polarization for a single water molecule demonstrably improves the description of the many-body polarization energy in all cases. This study provides a proof of principle for extending our protocol for developing a general purpose anisotropic polarizable force field for other biological and material functional groups to better describe complex and asymmetric environments for which accurate polarization models are most needed.