Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.
Phys Chem Chem Phys. 2018 Sep 12;20(35):23025-23033. doi: 10.1039/c8cp04056g.
By combining large basis and complete basis set (CBS) extrapolations of the coupled-cluster equilibrium geometry results with rovibrational and relativistic corrections, we demonstrate that it is possible to achieve near-quantitative accuracy for the NMR shielding constants in three group 15 trifluorides - NF3, PF3 and AsF3. These systems provide a rich test set for the calculation of dynamic electron correlation effects on NMR shielding constants. Basis sets as large as aug-cc-pCV6Z were employed, together with coupled-cluster expansion up to CCSDT, at the CCSD(T)/aug-cc-pCVTZ optimised geometries. The results of this work serve to highlight the application of state-of-the-art theoretical techniques which can be employed to guide and supplement NMR experimentation. Combining chemical shifts (either from experiment or high-level calculations) has also enabled a revised reference 19F NMR shielding constant for gas phase CFCl3 to be determined.
通过组合耦合簇平衡几何结果的大基和完整基集（CBS）外推以及振转和相对论修正，我们证明了在三个第 15 族三氟化物-NF3、PF3 和 AsF3 中，实现 NMR 屏蔽常数的近定量精度是可能的。这些系统为计算 NMR 屏蔽常数中的动态电子相关效应提供了丰富的测试集。采用了大到 aug-cc-pCV6Z 的基集，并结合耦合簇展开至 CCSDT，在 CCSD(T)/aug-cc-pCVTZ 优化的几何形状上进行。这项工作的结果突出了应用最先进的理论技术，这些技术可用于指导和补充 NMR 实验。结合化学位移（无论是来自实验还是高水平计算），也能够确定气相 CFCl3 的修订后的参考 19F NMR 屏蔽常数。
