Theoretical studies of heavyhyphen;atom magnetic shielding in some small polyatomic molecules

摘要

Perturbed Hartreehyphen;Fock calculations are performed on the molecules CH4, C2H2, C2H4, C2H6, CH3F, CH3OH, H2O, NH3, and C6H6to obtain the heavyhyphen;atom NMR shielding constants and magnetic susceptibilities. Slaterhyphen;type atomic orbitals (STO's) are used as the basis set. Various aspects of this model, including the dependence on basishyphen;set size and on the origin of the vector potential, are examined. The results are compared with the available experimental data and with otherab initioand semiempirical treatments.