论文标题

关于偶极矩的计算:有关选择基集和理论水平的建议

On the Computation of Dipole Moments: A Recommendation on the Choice of the Basis Set and the Level of Theory

论文作者

Zapata, Juan Camilo, McKemmish, Laura K.

论文摘要

与实验数据一起,理论上预测的偶极矩代表了化学和物理科学不同分支的宝贵工具。随着可用的理论和基础集的多样性,必须仔细选择可靠的组合,以实现准确的预测。在最近的出版物(Arxiv:1709.05075 [Physics.chem-Ph])中,Hait和Head-Gordon在这方面迈出了第一步,通过提供适合这些目的的最佳密度功能的建议。但是,尚未进行广泛的研究以根据套装选择提供建议。在这里,当在偶极矩的计算中,当与9种不同级别的理论水平相结合时,我们通过评估38个单一至三​​重Zeta质量的通用基础基集的性能来阐明这一问题。计算是在具有114个小分子的数据集上进行的,其中包含第二行元素和第三行元素。我们将分析基于正则根平方错误(正则RMSE),因为此过程可确保离子物种的相对误差以及偶极矩值较小的物种的绝对误差。我们的结果表明,通过使用增强的双​​Zeta质量基集(即AUG-PCSEG-1,AUG-PCSEG-1,AUG-CC-PVDZ)以及混合功能以及混合功能(例如WB97X-V,SOGGA-V,SOGGA,SOGGA111-X),可以实现准确性和计算效率之间的最佳折衷。增强的三ZETA基集可以提高计算的准确性,但是与所提供的小改进相比,引入这种基集的计算成本很大。这些发现还突出了至关重要的作用,即在偶极矩的计算中增强在氢和非氢原子上发挥弥散功能的基础功能的关键作用。

Together with experimental data, theoretically predicted dipole moments represent a valuable tool for different branches in the chemical and physical sciences. With the diversity of levels of theory and basis sets available, a reliable combination must be carefully chosen in order to achieve accurate predictions. In a recent publication (arXiv:1709.05075 [physics.chem-ph]), Hait and Head-Gordon took a first step in this regard by providing recommendations on the best density functionals suitable for these purposes. However, no extensive study has been performed to provide recommendations on the basis set choice. Here, we shed some light into this matter by evaluating the performance of 38 general-purpose basis sets of single up to triple zeta-quality, when coupled with nine different levels of theory, in the computation of dipole moments. The calculations were performed on a data set with 114 small molecules containing second- and third-row elements. We based our analysis in regularised root mean square errors (regularised RMSE) as this procedure ensures relative errors for ionic species and absolute errors for species with small dipole moment values. Our results indicate that the best compromise between accuracy and computational efficiency is achieved by performing the computations with an augmented double zeta-quality basis set (i.e. aug-pc-1, aug-pcseg-1, aug-cc-pVDZ) together with a hybrid functional (e.g. wB97X-V, SOGGA11-X). Augmented triple-zeta basis sets could enhance the accuracy of the computations, but the computational cost of introducing such a basis set is substantial compared with the small improvement provided. These findings also highlight the crucial role that augmentation of the basis set with diffuse functions on both hydrogen and non-hydrogen atoms plays in the computation of dipole moments.

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