Ruthenium-Indenylidene Olefin Metathesis Catalyst with Enhanced Thermal Stability

International audienc

New ruthenium metathesis catalysts with chelating indenylidene ligands: synthesis, characterization and reactivity

International audienc

Excited state dynamics and energy transfer processes in YVO4:Er3+ crystals

An extensive investigation of the fluorescence dynamics of the (2H11/2, 4S3/2), 4F9/2, 4I9/2, 4I11/2, and 4I13/2, states was carried out for 0.1%, 1%, 2.5%, and 10% Er3+ doped in YVO4. The decay profiles of the luminescence of the 4S3/2 level of Er3+ (1.0%) obey the Inokuti-Hirayama model for energy transfer for an electric dipole-electric dipole interaction in the absence of diffusion among the donors. From the analysis we were able to calculate the critical distance, R0, and it was found to be 5.7 Å: The dipole-dipole coupling parameter was estimated to be 2.9 × 10-51 m6 s-1 and compared well to other well known systems. © 1997 American Institute of Physics

Optical spectroscopy, fluorescence dynamics and crystal-field analysis of Er3+ in YVO4

The polarized absorption spectra, emission spectra and fluorescence dynamics of Er3+ doped in YVO4 are presented and analyzed in detail. Judd-Ofelt theory is applied to the measured absorption data to calculate the radiative decay rates for the various transitions of Er3+ in YVO4. A comparison of the experimental fluorescence lifetimes and the calculated radiative transition rates is made. Thermalization of the 2H11/2 level from the lower-lying 4S3/2 is studied. Crystal-field analysis is performed that is based on a Hamiltonian of D2d point-group symmetry. A best-fit analysis is performed resulting in an rms deviation of 6.7 cm-1