Energy levels in CaWO<sub>4</sub>:Tb<sup>3+</sup>at high pressure

Mahlik, Sebastian; Cavalli, E.; Amer, M.; Boutinaud, Philippe

doi:10.1039/c5cp05442g

Cited by 16 publications

(13 citation statements)

References 44 publications

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“…For scheelite-type ZrGeO 4 (space group: I4 1 /a), according to the group theory analysis, 13 Raman active modes are predicted: 3A g + 5B g + 5E g . In agreement with the previous report, all 13 expected Raman modes are detected, as shown in Figure 2 with the symmetry assignment summarized in Table 1. 25 Out of these 13 Raman active modes, 7 are internal modes originated from GeO 4 tetrahedra.…”

Section: Resultssupporting

confidence: 92%

“…Several experiments and theoretical results have confirmed that the scheelite- and zircon-type compounds are rather sensitive to the external pressure, and pressure-induced phase transitions usually occur for these compounds during compression . For instance, scheelite-to-fergusonite phase transition for CaWO 4 , a typical scheelite-type material, has been confirmed at around 10.0 GPa under quasi-hydrostatic conditions. − The pressure induced phase transition from the zircon to scheelite structure has also been observed for the typical zircon structure material ZrSiO 4 . , Many other scheelite- and zircon-structured ABO 4 ternary oxides have also been extensively studied, and similar results were reported for other ABO 4 materials, including tungstates, molybdates, vanadates, and phosphates. − …”

Section: Introductionmentioning

confidence: 84%

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Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

et al. 2017

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As promising optical materials, the structures of scheelite- and zircon-type ZrGeO4 have been investigated by Raman spectroscopy at pressures up to 51.6 GPa using diamond anvil cells. For scheelite-type ZrGeO4, two reversible phase transitions at 16.2 and 41.2 GPa were identified from the Raman spectral profiles and pressure dependence of the Raman shift upon compression. The first transition can be interpreted as the change of the tetragonal scheelite structure to the monoclinic fergusonite structure. By comparison with a previously reported isomorphic crystal, we infer that the second high pressure phase likely has a monoclinic structure. The zircon-type ZrGeO4 initially transforms to a scheelite structure at ∼10.1 GPa, while such phase transformation is completed at around 24.6 GPa, and remains stable up to 37.6 GPa. Moreover, the zircon-to-scheelite phase transition is irreversible, and the high pressure scheelite structure cannot be recovered upon decompression. These phase transitions for different starting ZrGeO4 materials were unambiguously identified for the first time, and their contrasting structural stabilities as well as the transition mechanisms can be understood from the intrinsic characteristics of the crystal lattices. These results contribute to the understanding of the pressure behavior of very sparsely reported germinate compounds in the ABO4 family.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 84%

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

et al. 2017

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“…This method has been used to estimate the location of the ground states of Tb 3+ and Pr 3+ with respect to conduction band in many materials. [14][15][16][17][18][19][20][21][22][23][24] We have chosen Y 2 O 2 S doped with Eu 3+ and Y 2 O 2 S doped with Tb 3+ to demonstrate how high-pressure spectroscopy can be used to determine the energetic structures of dielectric hosts doped with Ln 3+ and Ln 2+ .…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic properties and location of the Tb³⁺ and Eu³⁺ energy levels in Y₂O₂S under high hydrostatic pressure

Behrendt

Mahlik

Szczodrowski

et al. 2016

Phys. Chem. Chem. Phys.

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In this contribution, an extensive spectroscopic study of Y2O2S doped with Eu(3+) and Tb(3+) is presented. Steady-state luminescence and luminescence excitation spectra as well as the time-resolved spectra and luminescence kinetics were obtained at high hydrostatic pressures up to 240 kbar. It was found that pressure quenches the luminescence from the (5)D3 excited state of Tb(3+) and recovers additional luminescence related to transitions from the (5)D3 state of Eu(3+). These effects are related to the pressure-induced increases in the energies of the ground electronic manifold 4f(n) of Eu(3+) and Tb(3+) ions with respect to the band edges. Analysis of the emission and excitation spectra allowed the estimation of the energies of the ground states of all lanthanide (Ln) ions (Ln(3+) and Ln(2+)) with respect to the valence and conduction bands edges of the Y2O2S host. The bandgap energy and difference between energies of the ground states of Ln(2+) and Ln(3+) have been calculated as functions of pressure. The experimental high-pressure spectroscopy results allow the calculation of the absolute values (calculated with respect to the vacuum level) of the energies and pressure-induced shifts of the conduction and valence band edges and the ground states of Ln(3+) and Ln(2+) ions in Y2O2S.

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“…We therefore estimate that both CT processes contribute to the edge of the excitation spectrum recorded at ambient pressure. Following the arguments developed recently in ref , we estimate the action of pressure on the Bi–V CT energy as follows: where d P expresses the pressure dependence of the Bi–V distance in YVO 4 –Bi 3+ . This parameter can be calculated from eq , incorporating in this equation a pressure-induced collapse of the Y–V distance of −0.0055 Å/GPa, as deduced from ref .…”

Section: Results and Discussionmentioning

confidence: 99%

Energy Level Structure of Bi³⁺ in Zircon and Scheelite Polymorphs of YVO₄

Mahlik

Amer²,

Boutinaud³

2016

J. Phys. Chem. C

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The luminescence properties of YVO4–Bi3+ are investigated under the action of hydrostatic pressure in the range 0–20 GPa and interpreted on the basis of empirical models and energy level diagrams. In the zircon phase, the pressure induces an energy downshift of the Bi–V charge transfer state and a correlated red shift of the emission maximum. The pressure-induced zircon-to-scheelite phase transition leads to an important shift of the Bi–V charge transfer emission to the deep red. This emission, reported for the first time in the scheelite polymorph, is strongly quenched at room temperature due to radiationless relaxation from the triplet states of vanadate units and from the Bi–V charge transfer state by crossover to lower-lying electronic states.

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Energy levels in CaWO₄:Tb³⁺at high pressure

Cited by 16 publications

References 44 publications

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

Spectroscopic properties and location of the Tb³⁺ and Eu³⁺ energy levels in Y₂O₂S under high hydrostatic pressure

Energy Level Structure of Bi³⁺ in Zircon and Scheelite Polymorphs of YVO₄

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Energy levels in CaWO4:Tb3+at high pressure

Cited by 16 publications

References 44 publications

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO4

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO4

Spectroscopic properties and location of the Tb3+ and Eu3+ energy levels in Y2O2S under high hydrostatic pressure

Energy Level Structure of Bi3+ in Zircon and Scheelite Polymorphs of YVO4

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Energy levels in CaWO₄:Tb³⁺at high pressure

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

Contrasting Structural Stabilities and New Pressure-Induced Polymorphic Transitions of Scheelite- and Zircon-Type ZrGeO₄

Spectroscopic properties and location of the Tb³⁺ and Eu³⁺ energy levels in Y₂O₂S under high hydrostatic pressure

Energy Level Structure of Bi³⁺ in Zircon and Scheelite Polymorphs of YVO₄