评估基于域的局部对自然轨道 (DLPNO) 对大规模超分子复合体中非共价相互作用的近似
Montgomery Gray1, John M Herbert1
1Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
The Journal of chemical physics
|August 6, 2024
概括
基于域的局部对自然轨道 (DLPNO) 的近似.
科学领域:
- 计算化学的计算化学
- 量子化学 是一个量子化学.
- 超分子化学 超分子化学
背景情况:
- 基于域的局部对自然轨道 (DLPNO) 近似对于将相关波函数模型扩展到大型分子系统至关重要.
- 它对大型超分子复合体中的分子间相互作用的准确性需要彻底验证.
- 非共价相互作用对电子密度尾巴和非局部分散敏感,这可以通过对自然轨道 (PNO) 的积极选来妥协.
研究的目的:
- 严格评估DLPNO近似用于计算大型超分子复合体中的分子间相互作用能量的忠实性.
- 在各种系统大小中评估DLPNO-MP2和DLPNO-CCSD方法的性能.
- 在大型系统上确定最佳条件和必要的校正,以准确进行DLPNO计算.
主要方法:
- 这项研究使用第二阶Møller-Plesset扰动理论 (MP2) 和配对集群理论测试了DLPNO近似,使用单元,双元和扰动三元 [CCSD(T) ].
- 在各种大型超分子复合体上进行了计算,包括纳米级的石墨烯二元体.
- 使用平衡校正,并通过不同的PNO查门将结果推断到正规极限.
主要成果:
- DLPNO-MP2相互作用能量对小二极体显示出良好的一致性 (在3%以内),但对较大的系统没有推断而恶化.
- 额外推算的DLPNO-MP2结果在1%以内与大石墨烯二元体的规范值一致,不论大小如何,当分散功能不存在时.
- 标准DLPNO-CCSD(T) 设置显示出大型复合体的显著误差 (2-6 kcal/mol),即使在DLPNO-CCSD(T1) 级.
结论:
- 对正规极限的推断和对称性校正对于大超分子系统的精确DLPNO-MP2计算至关重要.
- 基本集合中缺乏扩散函数对于可靠的推断和尺寸独立的准确性至关重要.
- 对于大型超分子复合体,标准DLPNO-CCSD (T) 近似值的可靠性较低,因此需要仔细考虑PNO值和基础集.
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