A molecular-dynamics study of the equation of state of water using a fluctuating-charge model

The equation of state (EOS) and critical constants are reported for a fluctuating-charge model of water, based on PρT data from a series of molecular dynamics (MD) calculations. Since unphysical divergence of the partial charges sometimes occurred in the course of MD calculations, the model (TIP4P-FQ) was slightly modified to avoid this erroneous behavior. The EOS was determined by fitting the calculated PρT data to a model EOS. The calculated critical constants are in good agreement with the experimental values.