Chemical-shift tensors of heavy nuclei in network solids: a DFT/ZORA investigation of Pb-207 chemical-shift tensors using the bond-valence method

摘要

Cluster models are used in calculation of Pb-207 NMR magnetic-shielding parameters of alpha-PbO, beta-PbO, Pb3O4, Pb2SnO4, PbF2, PbCl2, PbBr2, PbClOH, PbBrOH, PbIOH, PbSiO3, and Pb-3(PO4)(2). We examine the effects of cluster size, method of termination of the cluster, charge on the cluster, introduction of exact exchange, and relativistic effects on calculation of magnetic-shielding tensors with density functional theory. Proper termination of the cluster for a network solid, including approximations such as compensation of charge by the bond-valence (BV) method, is essential to provide results that agree with experiment. The inclusion of relativistic effects at the spin-orbit level for such heavy nuclei is an essential factor in achieving agreement with experiment.