Excited state diabatization on the cheap using DFT: Photoinduced electron and hole transfer
Excited state diabatization on the cheap using DFT: Photoinduced electron and hole transfer
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DOI：
10.1063/5.0035593
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发表时间：
2020-12-28
影响因子：
4.4
通讯作者：
Markland, Thomas E.
中科院分区：
文献类型：
--
作者：
Mao, Yuezhi;Montoya-Castillo, Andres;Markland, Thomas E.
激发态电子和空穴转移是光电异质结激子解离、电极光诱导电荷转移和光合反应中心电子转移等过程的基本步骤。非绝热态对应于电荷或激发局域态，如局部激发态和电荷转移态，为模拟和理解这些过程提供了一个物理上直观的框架。然而，从绝热电子态中获得精确的绝热态及其耦合通常会导致与低层次电子结构方法（如时变密度泛函理论）相结合时结果不准确，并且与基于波函数的高水平方法相结合时计算成本过高。本文介绍了一种基于密度泛函理论（DFT）的非绝热化方案，该方案利用绝对定域分子轨道（ALMOs）直接构建非绝热态，我们将其记为Delta -ALMO（MSDFT2）。我们证明，我们的方法结合了ALMO计算和Delta SCF技术来构建电子激发非绝热态，并使用我们的MSDFT2方案获得了它们与电荷转移态的耦合，为带电和不带电系统中的激发态电子和空穴转移提供了准确的结果，这些系统是DNA修复、供体-受体二元体中的电荷分离、发色团到溶剂的电子转移和单线态裂变的基础。该框架用于准确有效地构建激发态热场，并直接从DFT中评估它们的耦合，从而为模拟和阐明大型无序系统（如凝聚态系统）中的光致电子和空穴转移提供了一条途径。
Excited state electron and hole transfer underpin fundamental steps in processes such as exciton dissociation at photovoltaic heterojunctions, photoinduced charge transfer at electrodes, and electron transfer in photosynthetic reaction centers. Diabatic states corresponding to charge or excitation localized species, such as locally excited and charge transfer states, provide a physically intuitive framework to simulate and understand these processes. However, obtaining accurate diabatic states and their couplings from adiabatic electronic states generally leads to inaccurate results when combined with low-tier electronic structure methods, such as time-dependent density functional theory, and exorbitant computational cost when combined with high-level wavefunction-based methods. Here, we introduce a density functional theory (DFT)-based diabatization scheme that directly constructs the diabatic states using absolutely localized molecular orbitals (ALMOs), which we denote as Delta -ALMO(MSDFT2). We demonstrate that our method, which combines ALMO calculations with the Delta SCF technique to construct electronically excited diabatic states and obtains their couplings with charge-transfer states using our MSDFT2 scheme, gives accurate results for excited state electron and hole transfer in both charged and uncharged systems that underlie DNA repair, charge separation in donor-acceptor dyads, chromophore-to-solvent electron transfer, and singlet fission. This framework for the accurate and efficient construction of excited state diabats and evaluation of their couplings directly from DFT thus offers a route to simulate and elucidate photoinduced electron and hole transfer in large disordered systems, such as those encountered in the condensed phase.