Nephelauxetic effect and spin – Orbit interaction with Pm3+ and Ho3+ ions in crystals

Abstract

The nephelauxetic parameters βk = Fk (Ln3+)/Fk (Ln IV) have been determined, with k = 2, 4, 6, Ln3+ – lanthanide ion in crystal, and Ln IV – triply – charged lanthanide free ion. The Slater integrals Fk and the spin – orbit coupling constants ζ4f for Pm IV and Ho IV have been estimated by interpolation from experimental values for other Ln IV. The matrix elements A of spin – orbit interaction have been calculated for the ground levels of both ions, 5I4 and 5I8 respectively. The correlation between βk and the normalized ratios A(Ln3+)/A(Ln IV) in crystals has been considered a combined nephelauxetic effect of electrostatic and spin – orbit interactions. Stoichiometric or doped crystals containing Pm3+ or Ho3+ ions include simple and complex halogenides, oxides, oxohalides, phosphates, complex with organic ligand, and hydrates.