NMR spectra of symmetric molecules. I. The spin Hamiltonian for twofold symmetry

Abstract Symmetrized spin operators and an appropriate symmetrized basis greatly simplify the calculation of the NMR spectra of molecules with twofold symmetry. The Hamiltonian is factored to the full extent permitted by the twofold symmetry and any magnetic equivalence that is present. Equations are given to permit the calculation of all necessary matrix elements directly from the spin quantum numbers. Even for molecules with symmetrically equivalent pairs of magnetically equivalent groups, the usual laborious expansion of the symmetrized basis in terms of the original unsymmetrized basis is eliminated.