Demissie Taye B, Jaszuński Michał, Komorovsky Stanislav, Repisky Michal, Ruud Kenneth
Centre for Theoretical and Computational Chemistry, Department of Chemistry, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01 224 Warszawa, Poland.
J Chem Phys. 2015 Oct 28;143(16):164311. doi: 10.1063/1.4934533.
We present nuclear spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in (175)LuX and (197)AuX (X = (19)F, (35)Cl, (79)Br, (127)I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. The total nuclear spin-rotation constants determined by adding the relativistic corrections obtained from DFT calculations to the CCSD(T) values are in general in agreement with available experimental data, indicating that the computational approach followed in this study allows us to predict reliable results for the unknown spin-rotation constants in these molecules. The total NMR absolute shielding constants are determined for all the nuclei following the same approach as that applied for the nuclear spin-rotation constants. In most of the molecules, relativistic effects significantly change the computed shielding constants, demonstrating that straightforward application of the non-relativistic formula relating the electronic contribution to the nuclear spin-rotation constants and the paramagnetic contribution to the shielding constants does not yield correct results. We also analyze the origin of the unusually large absolute shielding constant and its relativistic correction of gold in AuF compared to the other gold monohalides.
我们给出了使用耦合簇单双激发并带有微扰三激发（CCSD(T)）校正理论、四分量相对论密度泛函理论（相对论DFT）和非相对论DFT计算得到的(175)LuX和(197)AuX（X = (19)F、(35)Cl、(79)Br、(127)I）中所有原子核的核自旋-旋转常数、绝对核磁共振（NMR）屏蔽常数和屏蔽跨度。通过将从DFT计算得到的相对论校正加到CCSD(T)值上所确定的总核自旋-旋转常数总体上与现有的实验数据一致，这表明本研究中采用的计算方法使我们能够预测这些分子中未知自旋-旋转常数的可靠结果。所有原子核的总NMR绝对屏蔽常数是按照与用于核自旋-旋转常数相同的方法确定的。在大多数分子中，相对论效应显著改变了计算得到的屏蔽常数，这表明直接应用将电子对核自旋-旋转常数的贡献与顺磁对屏蔽常数的贡献联系起来的非相对论公式不会产生正确结果。我们还分析了与其他金的一卤化物相比，AuF中异常大的绝对屏蔽常数及其金的相对论校正的起源。
