F →d transition energies of divalent lanthanides in inorganic compounds

Abstract

The systematic in the 4f n → 4f n−1 5dtransition energy of divalent lanthanides in inorganic compounds has beenstudied. Energies were derived from excitation and optical absorption spectragathered from the literature. Going through the lanthanide series from La2+ toYb2+, a characteristic variation is observed similar to that known for the trivalentlanthanides and the free atoms and free ions. Once the transition energy is knownfor one lanthanide in a compound, that of all others in that same compound canbe predicted. The value for the Stokes shift between fd excitation and df emissionappears independent of the lanthanide ion. For Gd2+ to Yb2+ both thespin-forbidden and the spin-allowed fd-transition energies are discussed.