Samsonova Irina, Tucker Gabrielle B, Alaal Naresh, Brorsen Kurt R
Department of Chemistry, University of Missouri, 601 S. College Ave, Columbia, Missouri65203, United States.
ACS Omega. 2023 Jan 25;8(5):5033-5041. doi: 10.1021/acsomega.2c07782. eCollection 2023 Feb 7.
Multicomponent methods are a conceptually simple way to include nuclear quantum effects into quantum chemistry calculations. In multicomponent methods, the electronic molecular orbitals are described using the linear combination of atomic orbitals approximation. This requires the selection of a one-particle electronic basis set which, in practice, is commonly a correlation-consistent basis set. In multicomponent method studies, it has been demonstrated that large electronic basis sets are required for quantum hydrogen nuclei to accurately describe electron-nuclear correlation. However, as we show in this study, much of the need for large electronic basis sets is due to the correlation-consistent electronic basis sets not being optimized to describe nuclear properties and electron-nuclear correlation. Herein, we introduce a series of correlation-consistent electronic basis sets for hydrogen atoms called cc-pVZ-mc with additional basis functions optimized to reproduce multicomponent density functional theory protonic densities. These new electronic basis sets are shown to yield better protonic densities with fewer electronic basis functions than the standard correlation-consistent basis sets and reproduce other protonic properties such as proton affinities and protonic excitation energies, even though they were not optimized for these purposes. The cc-pVZ-mc basis sets should enable multicomponent many-body calculations on larger systems due to the improved computational efficiency they provide for a given level of accuracy.
多组分方法是一种在概念上简单的将核量子效应纳入量子化学计算的方式。在多组分方法中，电子分子轨道使用原子轨道近似的线性组合来描述。这需要选择一个单粒子电子基组，在实际中，通常是一个相关一致基组。在多组分方法研究中，已经证明对于量子氢核而言，需要大的电子基组来准确描述电子 - 核相关性。然而，正如我们在本研究中所示，对大电子基组的许多需求是由于相关一致电子基组未针对描述核性质和电子 - 核相关性进行优化。在此，我们引入了一系列针对氢原子的称为cc - pVZ - mc的相关一致电子基组，其具有额外优化的基函数以重现多组分密度泛函理论质子密度。这些新的电子基组被证明在使用比标准相关一致基组更少的电子基函数时能产生更好的质子密度，并且能重现其他质子性质，如质子亲和能和质子激发能，尽管它们并非为此目的而优化。由于cc - pVZ - mc基组在给定精度水平下提供了更高的计算效率，它们应该能够实现对更大体系的多组分多体计算。
