Coupled cluster benchmarks of water monomers and dimers extracted from density-functional theory liquid water: the importance of monomer deformations.
Coupled cluster benchmarks of water monomers and dimers extracted from density-functional theory liquid water: the importance of monomer deformations.
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从密度泛函理论液态水中提取的水单体和二聚体的耦合簇基准：单体变形的重要性。
DOI：
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发表时间：
2009
影响因子：
4.4
通讯作者：
M. Scheffler
中科院分区：
文献类型：
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作者：
B. Santra;A. Michaelides;M. Scheffler
为了了解流行的密度泛函理论交换相关 (xc) 泛函在液态水模拟中的性能，从液态水的 PBE 模拟中提取水单体和二聚体，并使用单激发和双激发的耦合簇以及连接三元组的微扰校正进行检查 [CCSD(T)]。 CCSD(T) 表明，与两个气相平衡水单体相比，大多数二聚体是未结合的，这主要是因为液体内的单体具有扭曲的几何形状。在测试的三个 xc 官能团中，PBE 和 BLYP 倾向于预测二聚体内单体之间的解离能太大。我们证明这是因为使用这些泛函将单体扭曲成它们在液体中采用的几何形状的成本被系统性地低估了。 PBE0 很好地再现了 CCSD(T) 单体变形能，因此二聚体解离能比 PBE 和 BLYP 更准确。尽管这项研究仅限于水单体和二聚体，但本文报告的结果可以为在液态水的 BLYP 和 PBE 模拟中常规观察到的超结构径向分布函数提供解释，并且与其他相中的水和其他相关分子液体相关。
To understand the performance of popular density-functional theory exchange-correlation (xc) functionals in simulations of liquid water, water monomers and dimers were extracted from a PBE simulation of liquid water and examined with coupled cluster with single and double excitations plus a perturbative correction for connected triples [CCSD(T)]. CCSD(T) reveals that most of the dimers are unbound compared to two gas phase equilibrium water monomers, largely because monomers within the liquid have distorted geometries. Of the three xc functionals tested, PBE and BLYP tend to predict too large dissociation energies between monomers within the dimers. We show that this is because the cost to distort the monomers to the geometries they adopt in the liquid is systematically underestimated with these functionals. PBE0 reproduces the CCSD(T) monomer deformation energies very well and consequently the dimer dissociation energies much more accurately than PBE and BLYP. Although this study is limited to water monomers and dimers, the results reported here may provide an explanation for the overstructured radial distribution functions routinely observed in BLYP and PBE simulations of liquid water and are of relevance to water in other phases and to other associated molecular liquids.
影响因子：
4.4
作者：
Janesko, Benjamin G.;Scuseria, Gustavo E.
通讯作者：
Scuseria, Gustavo E.