Theoretical studies of heavy-atom magnetic shielding in some small polyatomic molecules

Abstract

Perturbed Hartree-Fock calculations are performed on the molecules CH4, C2H2, C2H4, C2H6, CH3F, CH3OH, H2O, NH3, and C6H6 to obtain the heavy-atom NMR shielding constants and magnetic susceptibilities. Slater-type atomic orbitals (STO's) are used as the basis set. Various aspects of this model, including the dependence on basis-set size and on the origin of the vector potential, are examined. The results are compared with the available experimental data and with other ab initio and semiempirical treatments.