A group theoretical study of f n systems in an environment of approximately icosahedral symmetry

Abstract

Group theoretical methods are developed to determine in a generalised format for an f n ion in a crystal field environment of icosahedral symmetry, the effect on the energy level scheme when a crystal field distortion is considered parallel to any direction. As an illustration, the effect on the g-tensor components are examined as a function of the magnitude and the direction of the crystal field distortion. All appropriate reduced matrix elements in group theoretical terminology are evaluated for the f n -ion ground states. Specific results are given for the f 3-ion case and compared with electron paramagnetic resonance, optical, and magnetic susceptibility data.