Building Water Models: A Different Approach.
Simplified classical water models are currently an indispensable component in practical atomistic simulations. Yet, despite several decades of intense research, these models are still far from perfect. Presented here is an alternative approach to constructing widely used point charge water models. In contrast to the conventional approach, we do not impose any geometry constraints on the model other than the symmetry. Instead, we optimize the distribution of point charges to best describe the "electrostatics" of the water molecule. The resulting "optimal" 3-charge, 4-point rigid water model (OPC) reproduces a comprehensive set of bulk properties significantly more accurately than commonly used rigid models: average error relative to experiment is 0.76%. Close agreement with experiment holds over a wide range of temperatures. The improvements in the proposed model extend beyond bulk properties: compared to common rigid models, predicted hydration free energies of small molecules using OPC are uniformly closer to experiment, with root-mean-square error <1 kcal/mol.
Department of Biomedical Engineering and Mechanics, Department of Computer Science, and Departments of Computer Science and Physics, Virginia Tech , Blacksburg, Virginia 24060, United States.
Saeed
S
Izadi
Department of Biomedical Engineering and Mechanics, Department of Computer Science, and Departments of Computer Science and Physics, Virginia Tech , Blacksburg, Virginia 24060, United States.
Ramu
R
Anandakrishnan
Department of Biomedical Engineering and Mechanics, Department of Computer Science, and Departments of Computer Science and Physics, Virginia Tech , Blacksburg, Virginia 24060, United States.
Alexey V
AV
Onufriev