Chair for Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, D-85747 Garching, Germany.
Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, D-14195 Berlin, Germany.
J Chem Theory Comput. 2020 Dec 8;16(12):7431-7443. doi: 10.1021/acs.jctc.0c00887. Epub 2020 Nov 10.
We address a long-standing ambiguity in the DFT-based projection-operator diabatization method for charge transfer couplings in donor-acceptor systems. It has long been known that the original method yields diabats which are not strictly fragment-localized due to mixing arising from basis-set orthogonalization. We demonstrate that this can contribute to a severe underestimation of coupling strengths and a spurious dependence on the choice of the basis set. As a remedy, we reformulate the method within a simple tight-binding model to generate diabats with increased localization, yielding a proper basis set convergence and improved performance for the general Hab11 benchmark set. Orthogonality of diabats is ensured either through symmetric Löwdin or asymmetric Gram-Schmid procedures, the latter of which offers to extend these improvements to asymmetric systems such as adsorbates on surfaces.
我们解决了在基于密度泛函理论的投影算符双态化方法中，在给体-受体体系中电荷转移耦合方面长期存在的模糊问题。长期以来，人们一直知道，由于基组正交化引起的混合，原始方法得到的双态并不严格是片段局部化的。我们证明，这可能导致耦合强度的严重低估和对基组选择的虚假依赖。作为补救措施，我们在一个简单的紧束缚模型中重新表述该方法，以生成具有增加局域化的双态，从而产生适当的基组收敛，并提高一般 Hab11 基准集的性能。双态的正交性通过对称 Löwdin 或不对称 Gram-Schmid 过程来保证，后者提供了将这些改进扩展到不对称体系（如表面上的吸附物）的方法。
