Six-site polarizable model of water based on the classical Drude oscillator.

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TitleSix-site polarizable model of water based on the classical Drude oscillator.
Publication TypeJournal Article
Year of Publication2013
AuthorsYu, W, Lopes, PEM, Roux, B, Mackerell, AD
JournalJ Chem Phys
Volume138
Issue3
Pagination034508
Date Published2013 Jan 21
ISSN1089-7690
KeywordsHydrogen Bonding, Molecular Dynamics Simulation, Oxygen, Water
Abstract

A polarizable water model, SWM6, was developed and optimized for liquid phase simulations under ambient conditions. Building upon the previously developed SWM4-NDP model, additional sites representing oxygen lone-pairs were introduced. The geometry of the sites is assumed to be rigid. Considering the large number of adjustable parameters, simulated annealing together with polynomial fitting was used to facilitate model optimization. The new water model was shown to yield the correct self-diffusion coefficient after taking the system size effect into account, and the dimer geometry is better reproduced than in the SWM4 models. Moreover, the experimental oxygen-oxygen radial distribution is better reproduced, indicating that the new model more accurately describes the local hydrogen bonding structure of bulk phase water. This was further validated by its ability to reproduce the experimental nuclear magnetic shielding and related chemical shift of the water hydrogen in the bulk phase, a property sensitive to the local hydrogen bonding structure. In addition, comparison of the liquid properties of the SWM6 model is made with those of a number of widely used additive and polarizable models. Overall, improved balance between the description of monomer, dimer, clustered, and bulk phase water is obtained with the new model compared to its SWM4-NDP polarizable predecessor, though application of the model requires an approximately twofold increase on computational resources.

DOI10.1063/1.4774577
Alternate JournalJ Chem Phys
PubMed ID23343286
PubMed Central IDPMC3562330
Grant ListR01 GM072558 / GM / NIGMS NIH HHS / United States
R01 GM070855 / GM / NIGMS NIH HHS / United States
GM051501 / GM / NIGMS NIH HHS / United States
GM070855 / GM / NIGMS NIH HHS / United States
R01 GM051501 / GM / NIGMS NIH HHS / United States
R29 GM051501 / GM / NIGMS NIH HHS / United States
GM072558 / GM / NIGMS NIH HHS / United States