Magnetic properties in terms of localized quantities. VI. Small hydrides, fluorides, and homonuclear molecules of phosphorus and silicon

Abstract

The magnetic susceptibility and the NMR chemical shift tensors (for P, Si, H, and F) are calculated by means of the individual gauge for localized orbitals (IGLO) method for various phosphorus and silicon compounds with single, double, and triple bonds. The choice of appropriate basis sets is studied in detail with the conclusion that on the whole an (11s, 7p, 2d) basis for P in the contraction (7s, 6p, 2d) is required, but for high accuracy three or four sets of d functions are necessary. Somewhat smaller basis sets are sufficient for Si. The susceptibilities and the chemical shifts are obtained as sums of contributions of localized MOs and can hence be interpreted directly. The dependence of the susceptibilities and the chemical shifts on changes of the geometry is also studied.