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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Analysis of Density-Functional Errors for Noncovalent Interactions between Charged Molecules
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Analysis of Density-Functional Errors for Noncovalent Interactions between Charged Molecules

机译：带电分子非共价相互作用的密度功能误差分析

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摘要

The study of the structure and chemistry of biological systems with density-functional theory requires an accurate description of intermolecular interactions involving charged moieties. While dispersion-corrected functionals accurately model noncovalent interactions in neutral systems, a systematic study of the performance and errors associated with intermolecular interactions between charged fragments is missing. We undertake this study by examining the performance of a series of dispersion-corrected functionals with varying degrees of exact exchange for the side-chain protein interactions from the BioFragment Database (BFDb) of Burns et al. (the SSI set). In general, hybrid functionals with 20-30% exact exchange are accurate across the board, with the lowest mean absolute errors of 0.11 kcal/mol obtained from the 20% exact-exchange BLYP and PW86PBE hybrids coupled with the exchange-hole dipole moment (XDM) dispersion model. In addition, our analysis shows that functionals with higher exact-exchange fractions overestimate the electrostatic contributions to the binding energies, and that GGA functionals overestimate zwitterion binding energies due to delocalization error and overestimated charge transfer. In addition, the (quite large) repulsion in the dications is systematically overestimated by all functionals, and the trends for the monoanionic and dianionic dimers can be successfully explained by appealing to the ability of the underlying GGA to describe Pauli repulsion, as given by its exchange enhancement factor. Going beyond studies of biomolecules, this latter result has important implications for selecting appropriate GGA functionals for applications to ionic solids and layered materials containing anion-anion interactions.
机译：具有密度功能理论的生物系统结构和化学的研究需要准确描述涉及带电部分的分子间相互作用。虽然色散校正的功能精确地模拟中性系统中的非共价相互作用，但缺少了与带电碎片之间与分子间相互作用相关的性能和误差的系统研究。我们通过检查一系列色散校正的功能的性能来进行这项研究，该功能具有不同程度的精确交换，从Burns等人的生物形式数据库（BFDB）的侧链蛋白质相互作用。 （SSI集）。通常，具有20-30％精确交换的混合功能在电路板上准确，平均绝对误差为0.11千卡/摩尔，从20％精确交换BLYP和PW86PBE混合动力加上交换孔偶极偶像（ XDM）分散模型。此外，我们的分析表明，具有更高精确交换级数的功能高估到绑定能量的静电贡献，并且GGA函数由于分层误差和高估电荷转移而高估倍干增合能量。此外，通过所有功能系统高估（相当大的）排斥，并且可以通过吸引潜在的GGA描述Pauli排斥的能力来成功解释单血管和Dianionic二聚体的趋势，如下所示换货增强因子。超越生物分子的研究，后一种结果对选择适当的GGA官能的应用具有重要意义，用于含有阴离子 - 阴离子相互作用的离子固体和层状材料。

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