ANOMALOUS FLUORESCENCE FEATURES OF EU2-PYROMORPHITE TYPE MATRICES( INAPATITE)

Divalent europium doped chloro-apatites, the well-known blue phosphor in high efficiency fluorescent lamps, exhibit anomalous fluorescence p roperties ascribed to photoionization process and the allied process. The photoionization properties of Eu2+-luminescent centre(s) in this s ystem of materials has profound dependence on the chemical constituent s of the matrix as exemplified by the diadochic substitution of (SiO4) (4-) for [(PO4)(3-) + Cl-]. The anomalous impurity trapped exciton emi ssion can be better observed in Ba-compound than in the Ca- and Sr ana logues, possibly due to the effect of the position of the conduction b and.