Komorovský Stanislav, Repiský Michal, Malkina Olga L, Malkin Vladimir G, Malkin Ondík Irina, Kaupp Martin
Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, Bratislava, Slovak Republic.
J Chem Phys. 2008 Mar 14;128(10):104101. doi: 10.1063/1.2837472.
A new relativistic four-component density functional approach for calculations of NMR shielding tensors has been developed and implemented. It is founded on the matrix formulation of the Dirac-Kohn-Sham (DKS) method. Initially, unperturbed equations are solved with the use of a restricted kinetically balanced basis set for the small component. The second-order coupled perturbed DKS method is then based on the use of restricted magnetically balanced basis sets for the small component. Benchmark relativistic calculations have been carried out for the (1)H and heavy-atom nuclear shielding tensors of the HX series (X=F,Cl,Br,I), where spin-orbit effects are known to be very pronounced. The restricted magnetically balanced basis set allows us to avoid additional approximations and/or strong basis set dependence which arises in some related approaches. The method provides an attractive alternative to existing approximate two-component methods with transformed Hamiltonians for relativistic calculations of chemical shifts and spin-spin coupling constants of heavy-atom systems. In particular, no picture-change effects arise in property calculations.
一种用于核磁共振屏蔽张量计算的新的相对论四分量密度泛函方法已被开发并实现。它基于狄拉克 - 科恩 - 沙姆（DKS）方法的矩阵形式。最初，使用针对小分量的受限动力学平衡基组求解未受微扰的方程。然后，二阶耦合微扰DKS方法基于对小分量使用受限磁平衡基组。对HX系列（X = F、Cl、Br、I）的（1）H和重原子核屏蔽张量进行了基准相对论计算，其中自旋 - 轨道效应已知非常显著。受限磁平衡基组使我们能够避免在一些相关方法中出现的额外近似和/或对基组的强烈依赖。该方法为现有的具有变换哈密顿量的近似二分量方法提供了一种有吸引力的替代方案，用于重原子系统化学位移和自旋 - 自旋耦合常数的相对论计算。特别是，在性质计算中不会出现图像变化效应。
