(86h) Development of New Coarse-Grained Water Model Using a Hybrid Coarse-Graining Approach

Water is one of the most common solvent used for industrial purposes. Development of an accurate and efficient water molecule force field for use in the molecular dynamics (MD) simulations is a challenging task. There is a number of different models for bulk water that are available for use in MD simulations. However, none of the available models are capable of satisfying the following three requirements at once: accuracy, efficiency, and simplicity. The objective of this work is to develop a computationally efficient force field for a water model from ab initio quantum chemistry data. This new model would accurately predict structure, dynamic, thermodynamic, and transport properties. To perform this task, multi-scale coarse-graining approach (MSCG) has been applied to ab initio quantum chemistry data. In MSCG atoms are grouped into beads, thus, decreasing the number of degrees of freedom. For an accurate structure prediction a new hybrid scheme has been applied combining MSCG method with an iterative Boltzmann inversion (IBI) coarse-graining method. The model developed by MSCG+IBI can be used to predict structure and thermal properties. However, it can’t predict the dynamics and transport properties of the system. To remedy this, a probability distribution function coarse-graining (PDF-CG) method has been used, which recovers the dynamics and transport properties. By combining MSCG+IBI and PDF-CG methods, a highly accurate and computationally efficient water model has been developed. This model may be used to perform coarse-grained molecular dynamics simulations of aqueous solutions of various liquids of interest.