The rate parameter K_{3} of solvent-solute energy transfer and the rate parameter K_{7b} for solvent-quencher energy transfer are determined experimentally under ultraviolet excitation for a system Ethyl 1 butyl-2-methyl-5 ethoxycarboxy methoxy indole-3-carboxylate (EBMEC) in a deoxygenated system comprising 1:9 mixture of toluene-cyclohexane as a function of temperature in the range of 20-70°C, using bromobenzene as a solvent quencher. The data is analysed in terms of compact equation formed by combining Voltz et al. and Birks and Conte models. The interaction distance for the energy transfer from the excited solvent to solute molecules and solvent to quencher molecules are determined using this equation. The magnitude of the interaction distance indicates that the excitation energy transfer takes place due to long-range interaction in the case of solvent-solute energy transfer and short-range interaction in the case of solvent quencher energy transfer in dilute systems.
The luminescence decay curves from the ^{4}F_{9/2} and ^{4}I_{9/2} states of the cubic hexachloroelpasolite crystals Cs_{2}NaEr_{x}Y_{1-x}Cl_{6} (x = 0.001÷1) have been measured over the temperature range 10-300 K. The ^{4}I_{9/2} state undergoes an electric dipole vibronic-electric dipole vibronic cross-relaxation process at 300 K, but this mechanism is inefficient below 165 K. Excitation into the ^{4}F_{9/2} state, results in emission in the green, blue and ultra violet regions. The up-conversion processes which could account for the ultraviolet emission are discussed.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.