Can Multiconfigurational Self-Consistent Field Theory and Density Functional Theory Correctly Predict the Ground State of Metal-Metal-Bonded Complexes?
Can Multiconfigurational Self-Consistent Field Theory and Density Functional Theory Correctly Predict the Ground State of Metal-Metal-Bonded Complexes?
复制标题
多构型自洽场论和密度泛函理论能否正确预测金属-金属键配合物的基态？
DOI：
10.1021/acs.jctc.5b00412
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发表时间：
2015
影响因子：
5.5
通讯作者：
L. Gagliardi
中科院分区：
文献类型：
--
作者：
Rebecca K. Carlson;S. Odoh;Stephen J. Tereniak;Connie C. Lu;L. Gagliardi
用波函数方法和密度泛函理论研究了具有较强金属-金属相互作用的二铁(FeFe)络合物和金属-金属键较弱的类似络合物(CoCo、CoMn、CoFe和FeMn)的电子结构。只有在活性空间包含了完整的3D和4D轨道后，双铁络合物中金属中心之间的离域和成键才能被完全捕获，这种情况最适合于受限活性空间(RAS)方法。与实验相比，截断包含的一组4D轨道会导致某些3D轨道的不适当局域化，导致基自旋态的错误描述以及自旋态能量的错误。利用密度泛函理论，一些局部泛函能够预测正确的基自旋态，并描述所有金属-金属络合物的化学键和结构性质。相反，一些精确交换的引入增加了3D轨道的局域化和错误的自旋态能量，这种情况对双铁络合物来说特别麻烦。
The electronic structure of a diiron (FeFe) complex with strong metal-metal interaction and those of analogous complexes (CoCo, CoMn, CoFe, and FeMn) with much weaker metal-metal bonding are investigated with wave function-based methods and density functional theory. The delocalization and bonding between the metal centers in the diiron complex is only fully captured after inclusion of the complete set of 3d and 4d orbitals in the active space, a situation best suited for restricted active space (RAS) approaches. Truncation of the included set of 4d orbitals results in inappropriate localization of some 3d orbitals, incorrect description of the ground spin state as well as wrong spin state energetics, as compared to experiment. Using density functional theory, some local functionals are able to predict the correct ground spin states, and describe the chemical bonding and structural properties of all the metal-metal complexes considered in this work. In contrast, the introduction of some exact exchange results in increased localization of 3d orbitals and wrong spin state energetics, a situation that is particularly troublesome for the diiron complex.