  A coarse-grained water model is developed using multistate iterative
Boltzmann inversion. Following previous work, the k-means algorithm is used to
dynamically map multiple water molecules to a single coarse-grained bead,
allowing the use of structure-based coarse-graining methods. The model is
derived to match the bulk and interfacial properties of liquid water and
improves upon previous work that used single state iterative Boltzmann
inversion. The model accurately reproduces the density and structural
correlations of water at 305 K and 1.0 atm, stability of a liquid droplet at
305 K, and shows little tendency to crystallize at physiological conditions.
This work also illustrates several advantages of using multistate iterative
Boltzmann inversion for deriving generally applicable coarse-grained
forcefields.
