Energy transfer from Tb³⁺ to Nd³⁺ in glycerol:D₂O solution and frozen glass

Abstract

The mechanism of energy transfer from Tb³⁺ to Nd³⁺ in glycerol:D₂O solution at 280 K, 300 K and in its frozen glass at 80 K, 120 K, 190 K and 250 K has been examined. Analysis of the intensity and lifetime measurements of ⁵D₄ level of Tb³⁺ shows that at 280 K and 300 K in solution the transfer rate varies as the square of the Nd³⁺ concentration. This suggests a dipole-dipole transfer in the glycerol:D₂O solution. However, at lower temperatures up to 190 K, where the solution freezes into a glass, the dependence observed is linear at lower Nd³⁺ concentrations and quadratic at higher concentrations. Moreover, the linear concentration dependence becomes more pronounced as the temperature of the glass is increased. This linear concentration dependence of the transfer rate and its temperature dependence have been ascribed to the migrational transfer accompanying the multipolar transfer. The coefficients of both the interactions at the above temperatures have been calculated.