论文标题
Kohn-Sham绝热连接模型的自洽实施,并改善了对强度限制的治疗
Self-Consistent Implementation of Kohn-Sham Adiabatic Connection Models with Improved Treatment of the Strong-Interaction Limit
论文作者
论文摘要
绝热连接模型(ACM)在弱和强相互作用的限制之间插值,是构建准确的交换相关功能的强大工具。如果包括二阶扰动理论的确切弱点扩展,那么这些功能的自洽实现是具有挑战性的,在文献中仍然没有。在这项工作中,我们通过提出一些流行的ACM功能的完全自洽场(SCF)实现来填补这一空白。在弱相互作用下使用二阶扰动理论,我们还引入了新的广义梯度近似值(GGA),超出了通常的点 - 加上 - 加上 - 限制模型,这是对强相互作用的前两个领先术语,这对于确保稳健性和可靠性至关重要。然后,我们评估了分子系统和原型强相关问题的SCF-ACM功能。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轨道的影响直接连接到ACM功能形式的准确性。对于H $ _2 $解离,SCF-ACM功能对标准功能产生了重大改进,这也要归功于将新的GGA用于强耦合功能。
Adiabatic connection models (ACMs), which interpolate between the limits of weak and strong interaction, are powerful tools to build accurate exchange-correlation functionals. If the exact weak-interaction expansion from second-order perturbation theory is included, a self-consistent implementation of these functionals is challenging and still absent in the literature. In this work we fill this gap by presenting a fully self-consistent-field (SCF) implementation of some popular ACM functionals. While using second-order perturbation theory at weak interactions, we have also introduced new generalised gradient approximations (GGA's), beyond the usual point-charge-plus-continuum model, for the first two leading terms at strong interactions, which are crucial to ensure robustness and reliability. We then assess the SCF-ACM functionals for molecular systems and for prototypical strong-correlation problems. We find that they perform well for both the total energy and the electronic density and that the impact of SCF orbitals is directly connected to the accuracy of the ACM functional form. For the H$_2$ dissociation the SCF-ACM functionals yield significant improvements with respect to standard functionals, also thanks to the use of the new GGA's for the strong-coupling functionals.