An interpretation of the spectra of bivalent rare-earth ions in crystals

Abstract

The 4fn– 15d configuration behaves according to a J1γn coupling scheme in crystals, where J1 is the total angular momentum of a Russell–Saunders term derived from 4fn– 1 and J1γn is a state of the 5d electron in the crystal field. The spectra of several ions in alkaline earth fluorides and of Sm2+ in alkali halides correspond to 4fn→J1γn transitions with Δ, the separation between γ3 and γ5 in Oh, and Efd, a coulombic parameter, both pointing to a similarity of effects on passing through each half of the series of rare earths.