Energy transfer with migration. Generalization of the Yokota-Tanimoto model for any kind of multipole interaction

The dynamics of luminescence decay is analyzed within the general scenario of randomly distributed ions with whatever multipole interaction, taking in to account energy transfer and migration processes among them. By applying Pade approximants to the Allinger and Blumen expression for the excited sta te population, a simple expression has been obtained which can be easily fi tted to experimental data. This expression can be considered a generalizati on of the dipole-dipole Yokota-Tanimoto equation. On the other hand, the de cay curves from the D-5(3) level of the Tb3+ ions in fluorozincate glasses have been measured for different Tb3+ concentrations. The results are analy zed in the framework of the proposed expression. (C) 1999 American Institut e of Physics. [S0021-9606(99)70927-X].