Ab initio and coupled-perturbed density functional theory estimation of zero-field splittings in MnII transition metal complexes.
Ab initio and coupled-perturbed density functional theory estimation of zero-field splittings in MnII transition metal complexes.
复制标题
MnII 过渡金属配合物中零场分裂的从头计算和耦合扰动密度泛函理论估计。
DOI：
--
复制
发表时间：
2008
影响因子：
2.9
通讯作者：
F. Neese
中科院分区：
文献类型：
--
作者：
S. Zein;F. Neese
本文对一系列锰(II)配位络合物零场分裂(ZFS)参数的预测方法进行了比较。测试集由锰(II)络合物组成，通过X射线衍射和高场电子顺磁共振实验对其进行了很好的表征。用密度泛函理论(DFT)和完全活化空间自洽场(CASSCF)方法计算了它们的ZFS参数。结果表明，最近引入的耦合扰动自旋轨道耦合(CP-SOC)方法[Neese，F.J.Chem]。太棒了。与混合密度泛函一起导致关联线的斜率(实验值与计算值的曲线图)基本上是统一的，前提是直接自旋-自旋相互作用被适当地包括在处理中。这不同于我们之前对同一系列络合物的DFT研究，其中发现D参数被严重高估[Zein，S.；Duboc，C.；Lubitz，W.；Neese，F.Inorg。化学。2008、47、134]。CASSCF方法已被用来评估ZFS在“从头算配体-场”类型的治疗中。这项研究表明，在这样的处理中，相关物理学的很大一部分被丢失了，因为只考虑了锰d-歧管内的激发。因此，发现了对D参数的严重低估。由于CASSCF计算结合准简并微扰理论处理了SOC的所有阶，我们仍然验证了二阶微扰理论在高自旋d(5)组态的情况下是适当的近似。
The paper presents a method comparison for the prediction of zero-field splitting (ZFS) parameters in a series of Mn (II) coordination complexes. The test set consists of Mn (II) complexes that are experimentally well-characterized by X-ray diffraction and high-field electron paramagnetic resonance. Their ZFS parameters have been calculated using density functional theory (DFT) as well as complete active space self-consistent field (CASSCF) methods. It is shown that the recently introduced coupled-perturbed spin-orbit coupling (CP-SOC) approach [ Neese, F. J. Chem. Phys. 2007, 127, 164112 ] together with hybrid-DFT functionals leads to a slope of the correlation line (plot of experimental vs calculated D values) that is essentially unity provided that the direct spin-spin interaction is properly included in the treatment. This is different from our previous DFT study on the same series of complexes where a severe overestimation of the D parameter has been found [ Zein, S. ; Duboc, C. ; Lubitz, W. ; Neese, F. Inorg. Chem. 2008, 47, 134 ]. CASSCF methods have been used to evaluate the ZFS in an "ab initio ligand-field" type treatment. The study demonstrates that a substantial part of the relevant physics is lost in such a treatment since only excitations within the manganese d-manifold are accounted for. Thus, a severe underestimation of the D parameter has been found. Because the CASSCF calculations in combination with quasidegenerate perturbation theory treats the SOC to all orders, we have nevertheless verified that second-order perturbation theory is an adequate approximation in the case of the high-spin d (5) configuration.