- P-ISSN 1225-0163
- E-ISSN 2288-8985
The energy transfer is observed in double-activator-doped LaOCl:Pr, Tb and LaOCl:Pr, Eu system. From laser excitation and fluorescence spectra, a peculiar process for energy transfer between the activators is found. The energy absorbed by <TEX>$Tb^{3+}$</TEX> is directly transferred to <TEX>$Pr^{3+}$</TEX> ion. A cascade relaxation of an excited <TEX>$Pr^{3+}$</TEX> level to lower level, <TEX>$^1D_2$</TEX> is induced by <TEX>$Eu^{3+}$</TEX>, <TEX>$Tb^{3+}$</TEX>, which has <TEX>$^7F_J$</TEX> ground levels like <TEX>$Eu^{3+}$</TEX> ion, does not affect the cascade relaxation. The result represents that the quantum state of ion is not absolute condition for the energy transfer and that the energy transfer is competitive between levels of activator when the activator ions are closely located.