Calculation of the Chemical Shifts by the Semi-empirical SCF MO Method for All Valence-elctron Systems

Abstract

Abstract The proton chemical shifts in the nuclear magnetic resonance spectra of CH4, C2H6, C2H4, H2CO, pyridine, and protonated pyridine were evaluated on the basis of Pople’s theory (J. Chem. Phys., 37, 53 (1962)) in which the shielding tensor is expressed in terms of the magnetic susceptibility of each atom in the molecule. The wave functions were obtained using a semi-empirical SCF MO method for valence-electron systems (Bull. Chem. Soc. Jap., 40, 536, 1017 (1967)). The 13C- and 14N- chemical shifts in the above compounds were calculated on the basis of the “Coupled Hartree-Fock perturbation theory.”