Density functional calculation of nuclear magnetic resonance chemical shifts

A current-density functional theory for the calculation of nuclear magnetic resonance chemical shifts is presented. If the Kohn–Sham orbitals are expanded in a finite basis set, one of the main problems is the strong dependency of the results with respect to a shift of the gauge origin of the vector potential which describes the external magnetic field. Two computational schemes implementing both the individual gauge for localized orbitals ~IGLO! and gauge including atomic orbitals ~GIAO! concepts, which overcome this problem by introducing distributed gauge origins, are presented in detail. A comparison of the density functional IGLO and GIAO schemes shows that IGLO is much more efficient if one neglects the current-dependent part of the density functional ~as is done in ‘‘uncoupled’’ density functional theory!, but that this advantage is less pronounced in the full current-density functional treatment. © 1995 American Institute of Physics.