Śmiga Szymon, Della Sala Fabio, Gori-Giorgi Paola, Fabiano Eduardo
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudziądzka 5, 87-100 Toruń, Poland.
Institute for Microelectronics and Microsystems (CNR-IMM), Campus Unisalento, Lecce, Via Monteroni 73100, Italy.
J Chem Theory Comput. 2022 Oct 11;18(10):5936-5947. doi: 10.1021/acs.jctc.2c00352. Epub 2022 Sep 12.
Adiabatic connection models (ACMs), which interpolate between the limits of weak and strong interaction, are powerful tools to build accurate exchange-correlation functionals. If the exact weak-interaction expansion from the second-order perturbation theory is included, a self-consistent implementation of these functionals is challenging and still absent in the literature. In this work, we fill this gap by presenting a fully self-consistent-field (SCF) implementation of some popular ACM functionals. While using second-order perturbation theory at weak interactions, we have also introduced new generalized gradient approximations (GGAs), beyond the usual point-charge-plus-continuum model, for the first two leading terms at strong interactions, which are crucial to ensure robustness and reliability. We then assess the SCF-ACM functionals for molecular systems and for prototypical strong-correlation problems. We find that they perform well for both the total energy and the electronic density and that the impact of SCF orbitals is directly connected to the accuracy of the ACM functional form. For the H dissociation, the SCF-ACM functionals yield significant improvements with respect to standard functionals also thanks to the use of the new GGAs for the strong-coupling functionals.
绝热连接模型（ACMs）可在弱相互作用和强相互作用的极限之间进行插值，是构建精确交换相关泛函的有力工具。如果包含二阶微扰理论中精确的弱相互作用展开式，这些泛函的自洽实现具有挑战性，且文献中仍未出现。在这项工作中，我们通过给出一些流行的ACM泛函的完全自洽场（SCF）实现来填补这一空白。在弱相互作用时使用二阶微扰理论的同时，我们还针对强相互作用的前两个主导项引入了超越通常点电荷加连续介质模型的新广义梯度近似（GGAs），这对于确保稳健性和可靠性至关重要。然后，我们评估了分子体系和典型强关联问题的SCF-ACM泛函。我们发现它们在总能量和电子密度方面都表现良好，并且SCF轨道的影响与ACM泛函形式的准确性直接相关。对于H解离，由于对强耦合泛函使用了新的GGAs，SCF-ACM泛函相对于标准泛函有显著改进。
