发表机构
University of Missouri（密苏里大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出多组分MP2-F12/3C(FIX)方法，将显式相关技术推广至电子-质子关联，并加入CABS单激发修正，显著降低电子基组需求，在aug-cc-pVDZ下即可恢复96-98%的外推CBS关联能。
AI 中文摘要
多组分方法利用电子结构理论的标准机制，对电子和原子核进行量子力学处理。先前的研究表明，在多组分多体微扰理论方法中，定量描述电子-核关联需要包含高角动量原子轨道的大电子基组，因此对大体系的计算可能变得不切实际。类似地，电子-电子关联能相对于最高原子轨道角动量的收敛缓慢，是仅对电子进行量子力学处理的标准电子结构理论中一个众所周知的问题，为此已引入了众多显式相关方法以缓解这种缓慢收敛。受单组分显式相关方法成功的启发，我们将单组分MP2-F12/3C(FIX)方法从电子-电子关联推广到电子-质子关联，以减少多组分计算中对大电子基组的需求。我们还实现了针对电子和质子的互补辅助基组（CABS）单激发修正。我们的计算表明，在测试的每个电子基组基数下，当PB4-D固定不变时，多组分MP2-F12电子-质子关联能与通过QZ-5Z逆三次外推得到的完全基组（CBS）估计值相差在几个百分点以内，其中aug-cc-pVDZ基组恢复了外推CBS电子-质子关联能的96-98%，并超过了aug-cc-pV5Z水平下常规多组分MP2的值。这些结果表明，显式相关方法可以显著降低多组分计算对电子基组的要求。
英文摘要
Multicomponent methods treat both electrons and nuclei quantum mechanically using the standard machinery of electronic structure theory. Previous work has demonstrated that quantitatively describing electron-nuclear correlation in multicomponent many-body perturbation theory methods requires large electronic basis sets with high-angular momentum atomic orbitals, and calculations on large systems can therefore become impractical. Similarly, the slow convergence of the electron-electron correlation energy with respect to highest atomic-orbital angular momentum is a well-known issue in standard electronic structure theory in which only the electrons are treated quantum mechanically, and numerous explicitly correlated methods have been introduced to mitigate this poor convergence. Motivated by the success of single-component explicitly correlated methods, we generalize the single-component MP2-F12/3C(FIX) approach for electron-electron correlation to electron-proton correlation to reduce the need for large electronic basis sets in multicomponent calculations. We also implement the complementary auxiliary basis set (CABS) singles correction for the electrons and protons. Our calculations show that the multicomponent MP2-F12 electron-proton correlation energy is within a few percent of the complete-basis-set (CBS) estimate obtained by QZ-5Z inverse-cubic extrapolation with PB4-D held fixed at every electronic basis-set cardinality tested, with the aug-cc-pVDZ basis set recovering 96-98% of the extrapolated CBS electron-proton correlation energy and exceeding the conventional multicomponent MP2 value at the aug-cc-pV5Z level. These results indicate that explicitly correlated methods can substantially reduce the electronic basis-set requirements of multicomponent calculations.
CommentsV2: corrected the attribution of the 6-term Gaussian geminal fit and the accompanying discussion (Sec. IV.B, Table 4); benchmark results unchanged
