Hyperfine‐Induced f↔f Transitions: Effective Operator Formulation

Abstract

The direct perturbing influence of the nuclear magnetic and electric multipole hyperfine interactions upon the amplitude of the f↔f electric dipole transitions is analyzed. In this approach, the role of the forcing mechanism is played by an interaction other than the crystal field potential, which is the origin of all existing theoretical models. In particular, new effective operators of the second order that result from the electric dipole hyperfine interactions and compete with the standard Judd–Ofelt terms are introduced. In addition, the tensorial structure of the third‐order effective operators that contribute to the transition amplitude is discussed, and attention is directed to the possibility and necessity of the introduction of a new parameterization scheme of f‐spectra that would be applicable for the description of the hypersensitivity and such transitions that are highly forbidden by the standard selection rules.