On the Theory of Electronic-Vibrational Interaction for Rare Earth and Actinide Series Ions in Crystals. II. Octahedral Complexes

Abstract

A method is presented for obtaining the selection rules for transitions between shielded 4fⁿ or 5fⁿ states of rare earth and actinide ions coupled to lattice modes in crystals. This extends our previous work which was limited to rigid vibrational motion of complexes in crystalline fields. The method is illustrated for ions in octahedral complexes at sites of either O_h or D_3d symmetry. It is clear from the examples how to apply to other complexes or to include interactions beyond the complex and thereby to obtain the effect of coupling lattice modes involving particles external to the complex. The method is contrasted with that applicable in the case of strong vibration‐electronic interaction, i.e., to unshielded electronic states.