Charge Transfer, Local Structure, and the Inductive Effect in Rare-Earth-Doped Inorganic Solids

The charge transfer (CT) process is widely present in inorganic compounds. However, the explanation of this process accounting the inductive effect was not reported. In this work, through the analysis of local structure about the second nearest cations (SNCs) in some compounds doped with trivalent lanthanide, we verify successfully the important role of the inductive effect in the CT process. By introducing electronegativity factor ∑ iχ i( Ai)/ N - x( M), and ionic radius factor ∑ i ri( Ai)/ N, the semiquantitative model is proposed. Strong positive correlation between the electronegativity factor and CT energy and strong negative correlation between the ionic radius factor and CT energy are given. At last, the interrelationship among these two inductive factors, the CT process, the change of local coordination structure, and the chemical composition is revealed. This work will facilitate our understanding of the CT process and the delicate role of the local structure and the inductive effect.