Abstract

We found that the excitation energy can be transfered from Mn²⁺ to Sm³⁺ in ZnS:Mn, Sm.⁽¹⁾ For a given concentration of Mn²⁺ (C_Mn), the energy transfer rate (P) varies with the concentration of Sm³⁺C_Sm), as shown in Fig.1. But, when C_Mn increases from lower than 10^-4 mol. to 10^-3mol., the corresponding dependence of P upon C_Sm changes from $\text{P}\propto {\text{C}}_{\text{Sm}}^{\text{2}}$ to P ∝ C_Sm. This result can be explained by the different paths of energy transfer : a single-step direct transfer from Mn²⁺ to Sm³⁺ for small C_Mn and a multistep diffusion limited transfer, Mn²⁺→ Mn²⁺→⋯⋯→ Sm³ for large C_Mn. According to the energy transfer theory of dipole-dipole interaction, for diffusion limited transfer⁽²⁾, ${\text{P=4πα}}^{\text{1/4}}{\text{D}}^{\text{3/4}}{\text{C}}_{\text{Sm}}$, where D is the diffusion coefficient, α is a constant. On the other hand, P is proportional to ${\text{C}}_{\text{Sm}}^{\text{2}}$ for direct transfer⁽³⁾.

© 1984 Optical Society of America