SPIN-ORBIT CORRECTION TO NMR SHIELDING CONSTANTS FROM DENSITY-FUNCTIONAL THEORY

A new method based on density functional theory for the calculation of spin-orbit corrections to NMR shielding constants is presented. This approach provides the opportunity of calculating the relativistic spin -orbit correction, based on a DFT method which incorporates correlatio n effects and with the use of a special choice of gauge origin. The in clusion of the one-electron spin-orbit operator brings the results for H-1 chemical shifts in HF, HCl, HBr and HI and C-13 chemical shifts i n halogenomethanes into good agreement with experiment. The calculated one-electron spin-orbit corrections depend strongly on the basis set quality.