Abstract
A reduction of the crystal electric field (CEF) splitting of the 7F1 multiplet of Eu3+ with decreasing temperature is observed. This extraordinary phenomenon is similar to the analogous pressure-induced reduction of the CEF splitting of this multiplet. It is unlikely that the temperature effect is due to a temperature-induced approach toward high symmetry because a temperature decrease is known to lower the site symmetry. Resonant electron-phonon interactions between the 7F1 states and optical phonons with similar energies which result in a repulsion of the lowest 7F1 state toward higher energy may be the origin of the pressure and temperature effects. A plot of the time-resolved fluorescence line-narrowing linewidths of the 5D0→7F1(ε{lunate}0) transition vs. excitation energy have a minimum at the absorption peak value. This minimum can be explained either by an accidental coincidence in the excitation energy of ions at different sites or by different rates of excitation transfer to acceptors when the donors are excited via the center or via the wings of the absorption profile.
Original language | English |
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Pages (from-to) | 329-337 |
Number of pages | 9 |
Journal | Journal of Luminescence |
Volume | 43 |
Issue number | 6 |
DOIs | |
State | Published - Aug 1989 |