Kudo K, Maeda H, Kawakubo T, Ootani Y, Funaki M, Fukui H
Kitami Institute of Technology, 165 Koencho, Kitami 090-8507, Japan.
J Chem Phys. 2006 Jun 14;124(22):224106. doi: 10.1063/1.2204606.
The normalized elimination of the small component (NESC) theory, recently proposed by Filatov and Cremer, is extended to include magnetic interactions and applied to the calculation of the nuclear magnetic shielding in HX (X=F, Cl, Br, I) systems. The NESC calculations are performed at the levels of the zeroth-order regular approximation (ZORA) and the second-order regular approximation (SORA). The calculations show that the NESC-ZORA results are very close to the NESC-SORA results, except for the shielding of the I nucleus. Both the NESC-ZORA and NESC-SORA calculations yield very similar results to the previously reported values obtained using the relativistic infinite-order two-component coupled Hartree-Fock method. The difference between NESC-ZORA and NESC-SORA results is significant for the shieldings of iodine.
菲拉托夫和克雷默最近提出的小分量归一化消除（NESC）理论被扩展到包含磁相互作用，并应用于HX（X = F、Cl、Br、I）体系中核磁屏蔽的计算。NESC计算是在零阶正则近似（ZORA）和二阶正则近似（SORA）水平上进行的。计算结果表明，除了碘核的屏蔽外，NESC-ZORA结果与NESC-SORA结果非常接近。NESC-ZORA和NESC-SORA计算都得出了与先前使用相对论无穷阶双分量耦合哈特里-福克方法获得的报告值非常相似的结果。对于碘的屏蔽，NESC-ZORA和NESC-SORA结果之间的差异很大。
