Correlation and relativistic effects in beta-PbO and other lead (II) oxides: A quantum ab initio explanation of Pb-207 NMR and XANES spectra

We examine correlation and relativistic effects on Ph-Ph and Pb-O interacti ons in beta -PbO with ab initio quantum calculations and Pb-207 NMR chemica l-shift-tensor analysis, We find a covalent-like Pb2+-Pb2+ interaction acco unts for many facets of the NMR spectroscopy and the X-ray absorption near- edge structure, as well as other spectroscopic properties. This covalent ef fect arises from the relativistic properties of the 6(P3/2(m=+/-1/2)) and 6 (P3/2(m=+/-1/2)) orbitals. The existence of such interactions in lead (II) oxides of her than beta -PbO may explain NMR and optical spectra of these m aterials as well. (C) 2001 Academic Press.