Comparison of interaction potentials of liquid water with respect to their consistency with neutron diffraction data of pure heavy water.

A number of interaction potential models for liquid water are scrutinized from the point of view of their compatibility with results of neutron diffraction experiments on pure heavy water. For the quantitative assessment a protocol developed recently [L. Pusztai et al., Chem. Phys. Lett. 457, 96 (2008)] using the reverse Monte Carlo method has been applied. The approach combines the experimental total scattering structure factor (tssf) and partial radial distribution functions (prdfs) from molecular dynamics simulations in a single structural model (particle configuration). Goodness-of-fit values to the three (O-O, O-H, and H-H) simulated prdfs and to the experimental tssf provided an unbiased measure characterizing the level of consistency between various interaction potentials and diffraction experiments. Out of the sets of prdfs investigated here, corresponding to SPCE, BJH, ST2, POL3, TIP4P, TIP4P-2005, TTMF3, and ENCS interaction potentials, the ones from the TIP4P-2005 potential proved to be the most consistent with the experimental neutron-weighted tssf of heavy water. More importantly, it is shown that none of the above interaction potentials are seriously inconsistent with the measured structure factor at ambient conditions.