Two-photon absorption spectroscopy is used to investigate the 8 S 7/2 → 6 P J , 6 I 7/2 transitions of Gd 3+ ions in the cubic elpasolite Cs 2 NaGdCl 6 . The Gd 3+ ions occupy a centro-symmetric site (O h ); so the odd terms of the crystal field vanish and the pure electric dipole transitions should not be observed in one-photon experiments. As a consequence the electric dipole allowed two-photon transitions involving the 6 I 7/2 and 6 P 3/2 excited states are well observed in contrast with their weakness in the one-photon spectrum. Furthermore the magnetic dipole character of the transitions to the 6 P 5/2 and 6 P 7/2 levels is confirmed. The occurrence of the one-photon transition to 6 P 3/2 is tentatively explained by the J mixing involving the 6 P 7/2 excited state. A qualitative analysis of the relative intensities of the transitions to the 6 P J and 6 I 7/2 levels is presented.Two-photon absorption spectroscopy is used to investigate the 8 S 7/2 → 6 P J , 6 I 7/2 transitions of Gd 3+ ions in the cubic elpasolite Cs 2 NaGdCl 6 . The Gd 3+ ions occupy a centro-symmetric site (O h ); so the odd terms of the crystal field vanish and the pure electric dipole transitions should not be observed in one-photon experiments. As a consequence the electric dipole allowed two-photon transitions involving the 6 I 7/2 and 6 P 3/2 excited states are well observed in contrast with their weakness in the one-photon spectrum. Furthermore the magnetic dipole character of the transitions to the 6 P 5/2 and 6 P 7/2 levels is confirmed. The occurrence of the one-photon transition to 6 P 3/2 is tentatively explained by the J mixing involving the 6 P 7/2 excited state. A qualitative analysis of the relative intensities of the transitions to the 6 P J and 6 I 7/2 levels is presented.

Journal of Physics Condensed MatterFeb 25, 199117 citations

Two-photon absorption spectroscopy of multisite Gd3+ in CaF2

C. D. Cordero-Montalvo

The energy levels of ${\mathrm{Gd}}^{3+}$ in the $^{6}\mathrm{P}$ , $^{6}\mathrm{I}$ , and $^{6}\mathrm{D}$ 4 ${f}^{7}$ configuration in cubic, tetragonal, and cluster sites in ${\mathrm{CaF}}_{2}$ have been excited by two-photon absorption. The relative two-photon intensities and polarization dependence show behavior which is similar to that previously observed for ${\mathrm{Gd}}^{3+}$ : ${\mathrm{LaF}}_{3}$ and ${\mathrm{Eu}}^{2+}$ : ${\mathrm{CaF}}_{2}$ and which requires higher-order perturbation theory in the virtual intermediate 4${f}^{6}$5d configuration.The energy levels of ${\mathrm{Gd}}^{3+}$ in the $^{6}\mathrm{P}$, $^{6}\mathrm{I}$, and $^{6}\mathrm{D}$ 4${f}^{7}$ configuration in cubic, tetragonal, and cluster sites in ${\mathrm{CaF}}_{2}$ have been excited by two-photon absorption. The relative two-photon intensities and polarization dependence show behavior which is similar to that previously observed for ${\mathrm{Gd}}^{3+}$:${\mathrm{LaF}}_{3}$ and ${\mathrm{Eu}}^{2+}$:${\mathrm{CaF}}_{2}$ and which requires higher-order perturbation theory in the virtual intermediate 4${f}^{6}$5d configuration.

Physical review. B, Condensed matterApr 15, 198510 citations

The energy levels of

{\mathrm{Gd}}^{3+}

in the

^{6}\mathrm{P}

^{6}\mathrm{I}

, and

^{6}\mathrm{D}

{f}^{7}

configuration in cubic, tetragonal, and cluster sites in

{\mathrm{CaF}}_{2}

have been excited by two-photon absorption. The relative two-photon intensities and polarization dependence show behavior which is similar to that previously observed for

{\mathrm{Gd}}^{3+}

{\mathrm{LaF}}_{3}

and

{\mathrm{Eu}}^{2+}

{\mathrm{CaF}}_{2}

and which requires higher-order perturbation theory in the virtual intermediate 4${f}^{6}$5d configuration.