An EXAFS study of the luminescent Bi3+ center in LaPO4---Bi

Abstract

In order to determine the oxygen coordination of the Bi3+ ion in LaPO4---Bi, extended X-ray absorption fine structure (EXAFS) spectra were measured of BiPO4 and LaPO4---Bi. Analysis of the EXAFS data shows that the Bi3+ ion in LaPO4---Bi occupies the La3+ site, but that the oxygen coordination of the Bi3+ ion is distorted relative to that of La3+ in undoped LaPO4. The oxygen coordination shows a resemblance to that of Bi3+ in BiPO4. The importance of these results for the Bi3+ luminescence is discussed.