We note that the average structural properties are similar in the NVT and NVE ensembles 180 . Additionally, the replacement of hydrogen atoms with deuterium has little effect on structural properties when the ionic motion is treated classically . How-ever, the use of deuterated water can affect dynamical properties, such as the diffusion coefficient. Therefore, it is important to rely on heavy water data when validating D 2 O simulations against experimental results.