5 d electron delocalization of Ce 3 + and Pr <…
2005; American Physical Society; Volume: 71; Issue: 16 Linguagem: Inglês
10.1103/physrevb.71.165120
ISSN1550-235X
AutoresErik van der Kolk, P. Dorenbos, C.W.E. van Eijk, S. A. Basun, G. F. Imbusch, W. M. Yen,
Tópico(s)Glass properties and applications
ResumoThe energies of the $5d$ excited states of ${\mathrm{Ce}}^{3+}$ and ${\mathrm{Pr}}^{3+}$ impurities relative to the conduction band of the insulators ${\mathrm{Y}}_{2}\mathrm{Si}{\mathrm{O}}_{5}$ and ${\mathrm{Lu}}_{2}\mathrm{Si}{\mathrm{O}}_{5}$ were investigated through a temperature and spectrally resolved photoconductivity study. The effective ionization barrier of ${\mathrm{Pr}}^{3+}$ from the $5d$ state to the conduction band is found to be $0.15\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ smaller than that of ${\mathrm{Ce}}^{3+}$ in both ${\mathrm{Y}}_{2}\mathrm{Si}{\mathrm{O}}_{5}$ and ${\mathrm{Lu}}_{2}\mathrm{Si}{\mathrm{O}}_{5}$. The difference is explained by a model, represented by rate equations, that takes into account interconfigurational $4f5d\ensuremath{\rightarrow}4{f}^{2}$ relaxation for ${\mathrm{Pr}}^{3+}$, a process that is absent for ${\mathrm{Ce}}^{3+}$.
Referência(s)