Basis-Set and Correlation-Effects in the Calculation of Selenium Nmr Shieldings
by Magyarfalvi, G.; Pulay, P.
Accurate ab initio GIAO calculations of Se-77 chemical shieldings in SeH2, SeHCH3 and Se (CH3)2 are reported. The Calculations closely reproduce the experimental relative chemical shifts of these molecules. The extension of the basis sets with p, d and f functions on the selenium atom improves the chemical shifts at the SCF level values, but quantitativeness is only achieved at the MP2 level. The effect of conformation on the chemical shieldings is also discussed.