Effects of distorted lattice and nonequal-valvence substitution on the long lasting phosphorescence of [Eu.sup.2+] and [Gd.sup.3+] doped R[Mg.sub.2][([PO.sub.4]).sub.2] (R = Sr,Ba) phosphors

Several studies are conducted to explain the various effects of the distorted lattice and nonequal-valence substitution observed on the long lasting phosphorescence of [Eu.sup.2+] and [Gd.sup.3+] doped R[Mg.sub.2][([PO.sub.4]).sub.2] (R = Sr,Ba) phosphors. The electron storage ability of the compounds is shown to get highly enhanced because of the codoping of [Gd.sup.3+].