Systematic investigation on the geometric dependence of the calculated nuclear magnetic shielding constants.
We perform a systematic examination on the dependence of the calculated nuclear magnetic shielding constants on the chosen geometry for a selective set of density functional methods of B3LYP, PBE0, and OPBE. We find that the OPBE exchange-correlation functional performs remarkably well when either the optimized geometries or the experimental geometries are used. The popular B3LYP and PBE0 functionals have a clear tendency of deshielding, giving shieldings that are usually too low and shifts that are usually too high, at the experimental geometries. Combined with the Hartree-Fock geometries, however, much improved magnetic constants are obtained for B3LYP and PBE0, due to the compensation effect from the systematic underestimation of bond lengths by the Hartree-Fock method.
Zhang
Ying
Y
State Key Laboratory of Physical Chemistry of Solid Surfaces, Center for Theoretical Chemistry, College for Chemistry and Chemical Engineering, Xiamen University, 361005, China.
Xu
Xin
X
Yan
Yijing
Y