THEORY OF ELECTRIC-FIELD EFFECTS ON ELECTRON-SPIN-RESONANCE HYPERFINECOUPLINGS

A quantum mechanical theory of the effects of a uniform electric held on electron-spin-resonance hyperfine couplings is presented. The elect ric-field effects are described in terms of perturbation coefficients which can be used to probe the local symmetry as well as the strength of the electric field at paramagnetic sites in a solid. Results are pr esented for the first-order perturbation coefficients describing the B loembergen effect (linear electric-field effect on hyperfine coupling tensor) for the O atom and the OH radical.