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arXiv · 2107.05881

A CCSD(T)-based permutationally invariant polynomial 4-body potential for water

Apurba Nandi·Chen Qu·Paul L. Houston·Riccardo Conte·Joel M. Bowman
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Abstract

We report a permutationally invariant polynomial (PIP) potential energy surface for the water 4-body interaction. This 12-atom PES is a fit to 2119, symmetry-unique, CCSD(T)-F12a/haTZ (aug-cc-pVTZ basis for 'O' atom and cc-pVTZ basis for 'H' atom) 4-b interaction energies. These come from low-level, direct-dynamics calculations, tetramer fragments from an MD water simulation at 300 K, and from the water hexamer, heptamer, decamer, and 13-mer clusters. The PIP basis is purified to ensure that the 4-b potential goes rigorously to zero in monomer+trimer and dimer+dimer dissociations for all possible such fragments. The 4-b energies of isomers of the hexamer calculated with the new surface are shown to be in better agreement with benchmark CCSD(T) results than those from the MB-pol potential. Other tests validate the high-fidelity of the PES.

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Apurba Nandi, Chen Qu, Paul L. Houston, Riccardo Conte, Joel M. Bowman. 2021-07-13. A CCSD(T)-based permutationally invariant polynomial 4-body potential for water. https://doi.org/10.1021/acs.jpclett.1c03152

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