Sharma Prachi, Bernales Varinia, Knecht Stefan, Truhlar Donald G, Gagliardi Laura
Department of Chemistry , Chemical Theory Center , Minnesota Supercomputing Institute , University of Minnesota , Minneapolis , Minnesota 55455 , USA . Email:
Laboratory of Physical Chemistry , ETH Zürich , Vladimir-Prelog-Weg 2 , CH-8093 Zürich , Switzerland . Email:
Chem Sci. 2018 Nov 26;10(6):1716-1723. doi: 10.1039/c8sc03569e. eCollection 2019 Feb 14.
The density matrix renormalization group (DMRG) is a powerful method to treat static correlation. Here we present an inexpensive way to calculate correlation energy starting from a DMRG wave function using pair-density functional theory (PDFT). We applied this new approach, called DMRG-PDFT, to study singlet-triplet gaps in polyacenes and polyacetylenes that require active spaces larger than the feasibility limit of the conventional complete active-space self-consistent field (CASSCF) method. The results match reasonably well with the most reliable literature values and have only a moderate dependence on the compression of the initial DMRG wave function. Furthermore, DMRG-PDFT is significantly less expensive than other commonly applied ways of adding additional correlation to DMRG, such as DMRG followed by multireference perturbation theory or multireference configuration interaction.
密度矩阵重整化群（DMRG）是处理静态关联的一种强大方法。在此，我们提出一种低成本的方法，即从DMRG波函数出发，利用对密度泛函理论（PDFT）来计算关联能。我们将这种称为DMRG - PDFT的新方法应用于研究并四苯和聚乙炔中的单重态 - 三重态能隙，这些体系所需的活性空间大于传统完全活性空间自洽场（CASSCF）方法的可行性极限。结果与最可靠的文献值相当吻合，并且对初始DMRG波函数的压缩仅有适度的依赖性。此外，DMRG - PDFT比其他常用的给DMRG添加额外关联的方法成本低得多，例如先进行DMRG然后进行多参考微扰理论或多参考组态相互作用。
