Figure 3.

Quality score distribution of test water models in the space of dipole (μ) and quadrupole (Q_T). Scores (from 0 to 10) are calculated based on the accuracy of predicted values for six key properties of liquid water (see text). The resulting proposed optimal model is termed OPC. For reference, the μ and Q_T values of several commonly used water models (triangles, quality score given by the color at the symbol position) and quantum calculations (squares) are placed on the same map (see also Table 1). The actual positions of AIMD1 and TIP5P are slightly modified to fit in the range shown.