On the transferability of three water models developed by adaptive force matching

by Hu, Hongyi; Ma, Zhonghua; Wang, Feng

Water is perhaps the most simulated liq. Recently three water models have been developed following the adaptive force matching (AFM) method that provides excellent predictions of water properties with only electronic structure information as a ref. Compared to many other electronic structure based force fields that rely on fairly sophisticated energy expressions, the AFM water models use point-charge based energy expressions that are supported by most popular mol. dynamics packages. An outstanding question regarding simple force fields is whether such force fields provide reasonable transferability outside of their conditions of parameterization. A survey of three AFM water models, B3LYPD-4F, BLYPSP-4F, and WAIL are provided for simulations under conditions ranging from the m.p. up to the crit. point. By including ice-Ih configurations in the training set, the WAIL potential predicts the melting temperate, TM, of ice-Ih correctly. Without training for ice, BLYPSP-4F underestimates TM by about 15 K. Interestingly, the B3LYPD-4F model gives a TM 14 K too high. The overestimation of TM by B3LYPD-4F mostly likely reflects a deficiency of the B3LYP ref. The BLYPSP-4F model gives the best est. of the boiling temp. TB and is arguably the best potential for simulating water in the temp. range from TM to TB. None of the three AFM potentials provides a good description of the crit. point. Although the B3LYPD-4F model gives the correct crit. temp. TC and crit. d. ? C, there are good reasons to believe the agreement is reached fortuitously. Links to Gromacs input files for the three water models are provided at the end of the paper.

arXiv.org, e-Print Archive, Physics
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