ABSTRACT
As an example, we discuss Gdl-xEuxMgBsOlO. In this compound, the rare-earth ions are incorporated in linear zigzag chains. The shortest distance between ions in the chains is about 4 A; the distance between the chains is about 6 A. It has been shown that the energy transfer mechanism in this compound has a one-dimensional character (Buijs, 1978). As the interchain and intrachain distance are not very different, this similarity points to exchange interaction as the mechanism responsible for the energy transfer process, because the process is sensitive to short-order distance variations. The sensitivity nicely illustrates how knowledge of the crystal structure is necessary to understand details of the processes leading to transport of energy in luminescent materials.
