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Comparison of approximate intermolecular potentials for ab initio fragment calculations on medium sized N-heterocycles
Journal of Computational Chemistry ( IF 3 ) Pub Date : 2022-04-28 , DOI: 10.1002/jcc.26866
Bónis Barcza 1 , Ádám B Szirmai 1 , Katalin J Szántó 1 , Attila Tajti 1 , Péter G Szalay 1
Affiliation  

The ground state intermolecular potential of bimolecular complexes of N-heterocycles is analyzed for the impact of individual terms in the interaction energy as provided by various, conceptually different theories. Novel combinations with several formulations of the electrostatic, Pauli repulsion, and dispersion contributions are tested at both short- and long-distance sides of the potential energy surface, for various alignments of the pyrrole dimer as well as the cytosine–uracil complex. The integration of a DFT/CCSD density embedding scheme, with dispersion terms from the effective fragment potential (EFP) method is found to provide good agreement with a reference CCSD(T) potential overall; simultaneously, a quantum mechanics/molecular mechanics approach using CHELPG atomic point charges for the electrostatic interaction, augmented by EFP dispersion and Pauli repulsion, comes also close to the reference result. Both schemes have the advantage of not relying on predefined force fields; rather, the interaction parameters can be determined for the system under study, thus being excellent candidates for ab initio modeling.

中文翻译:

中型 N-杂环从头算片段计算的近似分子间势的比较

分析了 N-杂环双分子配合物的基态分子间势,以了解各个项对相互作用能的影响,这些影响由各种概念上不同的理论提供。在势能表面的短距离和长距离侧测试了具有静电、泡利排斥和色散贡献的几种配方的新组合,用于吡咯二聚体以及胞嘧啶-尿嘧啶复合物的各种排列。发现 DFT/CCSD 密度嵌入方案与有效碎片势 (EFP) 方法的色散项的集成与参考 CCSD(T) 势的总体一致性很好;同时,使用 CHELPG 原子点电荷进行静电相互作用的量子力学/分子力学方法,通过 EFP 色散和泡利斥力增强,也接近参考结果。两种方案都具有不依赖于预定义力场的优点;相反,可以确定所研究系统的交互参数,因此是从头开始建模的优秀候选者。
更新日期:2022-04-28
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