Improved NMR chemical shifts in density functional theory

Density functional theory isotropic NMR chemical shifts are determined for 36 molecules containing H, C, N, O and F. Results from the KT2 GGA functional, which is known to provide high quality absolute shieldings, are compared with those from LDA, HCTH, B97-2, B3LYP, PBE0, SAOP and MKS(B97-2). At GGA geometries, the most accurate chemical shifts are obtained with MKS(B97-2), although the method is relatively computationally demanding. The computationally simple KT2 functional provides the next best results, which are a notable improvement over those from the other methods, particularly for 17O. KT2 chemical shifts improve further when determined at optimised geometries.