Comparison of the spectroscopic behaviour of single crystals of lanthanide halides (X = Cl, Br)

Oczko, G.; Macalik, L.; Legendziewicz, J.; Hanuza, J.

doi:10.1016/j.jallcom.2004.03.009

Cited by 19 publications

(6 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides the two steep absorption thresholds attributed to valence to conduction band transitions, the diffuse reflectance spectra of Pr 4 O 4 Se[Se 2 ], Nd 4 O 4 Se[Se 2 ], and Sm 4 O 4 Se[Se 2 ] show a series of characteristic lines between 0.5−1.0 eV for M = Pr, 1.3−1.7 eV for M = Nd, and 0.5−1.5 eV for M = Sm, which correspond to typical f–f transitions for M 3+ cations (M = Pr, Nd, Sm). This indicates that the 4f electrons are strongly localized, and the optical band gaps of these compounds are only slightly influenced by the different cations in M 4 O 4 Se[Se 2 ] (M = La, Pr, Nd, Sm).…”

Section: Physical Propertiesmentioning

confidence: 99%

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

et al. 2008

View full text Add to dashboard Cite

The rare-earth metal(III) oxide selenides of the formula La4O4Se[Se2], Ce4O4Se[Se2], Pr4O4Se[Se2], Nd4O4Se[Se2], and Sm4O4Se[Se2] were synthesized from a mixture of the elements with selenium dioxide as the oxygen source at 750 degrees C. Single crystal X-ray diffraction was used to determine their crystal structures. The isostructural compounds M4O4Se[Se2] (M=La, Ce, Pr, Nd, Sm) crystallize in the orthorhombic space group Amm2 with cell dimensions a=857.94(7), b=409.44(4), c=1316.49(8) pm for M=La; a=851.37(6), b=404.82(3), c=1296.83(9) pm for M=Ce; a=849.92(6), b=402.78(3), c=1292.57(9) pm for M=Pr; a=845.68(4), b=398.83(2), c=1282.45(7) pm for M=Nd; and a=840.08(5), b=394.04(3), c=1263.83(6) pm for M=Sm (Z=2). In their crystal structures, Se2- anions as well as [Se-Se]2- dumbbells interconnect {[M4O4]4+} infinity 2 layers. These layers are composed of three crystallographically different, distorted [OM4]10+ tetrahedra, which are linked via four common edges. The compounds exhibit strong Raman active modes at around 215 cm(-1), which can be assigned to the Se-Se stretching vibration. Optical band gaps for La4O4Se[Se2], Ce4O4Se[Se2], Pr4O4Se[Se2], Nd4O4Se[Se2], and Sm4O4Se[Se2] were derived from diffuse reflectance spectra. The energy values at which absorption takes place are typical for semiconducting materials. For the compounds M4O4Se[Se2] (M=La, Pr, Nd, Sm) the fundamental band gaps, caused by transitions from the valence band to the conduction band (VB-CB), lie around 1.9 eV, while for M=Ce an absorption edge occurs at around 1.7 eV, which can be assigned to f-d transitions of Ce3+. Magnetic susceptibility measurements of Ce4O4Se[Se2] and Nd4O4Se[Se2] show Curie-Weiss behavior above 150 K with derived experimental magnetic moments of 2.5 micro B/Ce and 3.7 micro B/Nd and Weiss constants of theta p=-64.9 K and theta p=-27.8 K for the cerium and neodymium compounds, respectively. Down to 1.8 K no long-range magnetic ordering could be detected. Thus, the large negative values for theta p indicate the presence of strong magnetic frustration within the compounds, which is due to the geometric arrangement of the magnetic sublattice in form of [OM4]10+ tetrahedra.

show abstract

Section: Physical Propertiesmentioning

confidence: 99%

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Hence, the following split takes place: 2 D → 2 A + 2 E (1) + 2 E (2) . Notably, in the single crystals of the early lanthanide ions, also containing the water of crystallization, the coordination number is nine, as in the case of Ce 3+ , whereas around the smaller lanthanides (of higher atomic number) only eight ligands can be coordinated [12].…”

Section: Introductionmentioning

confidence: 99%

Explanation for the Multi-Component Scintillation of Cerium Fluoride Through the Equilibrium and Photophysical Investigation of Cerium(III)-Fluoro Complexes

2019

View full text Add to dashboard Cite

CeF3 displays favorable scintillation properties, which have been utilized for decades in various solid-state systems. Its emission undergoes multi-component decays, which were interpreted by lattice defects and so-called intrinsic features herein. This study of the complex equilibria in connection with photophysical behavior of the cerium(III)-fluoride system in solution gave us the possibility to reveal the individual contribution of the [CeIIIFx(H2O)9−x]3−x species to the photoluminescence. Spectrophotometry and spectrofluorometry (also in time-resolved mode) were used, and combined with sophisticated evaluation methods regarding both the complex equilibria and the kinetics of the photoinduced processes. The individual photophysical parameters of the [CeIIIFx(H2O)9−x]3−x complexes were determined. For the kinetic evaluation, three methods of various simplifications were applied and compared. The results indicated that the rates of some excited-state equilibrium processes were comparable to those of the emission decay steps. Our results also contribute to the explanation of the multi-component emission decays in the CeF3-containing scintillators, due to the various coordination environments of Ce3+, which can be affected by the excitation leading to the dissociation of the metal-ligand bonds.

show abstract

“…They are extensively used in optical and scintillation [1][2][3][4][5] devices and are attractive components for doses in high-intensity discharge lamps and new highly efficient light sources with energy saving features [6]. The wide band gap materials like fluorides and other halides co-doped by lanthanide ions provide valuable insight into many aspects of luminescence centers and have wide applications [7].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and transport properties of the PrBr3–RbBr binary system

Rycerz

Ingier-Stocka

Berkani

et al. 2010

Journal of Alloys and Compounds

View full text Add to dashboard Cite

Comparison of the spectroscopic behaviour of single crystals of lanthanide halides (X = Cl, Br)

Cited by 19 publications

References 23 publications

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

Explanation for the Multi-Component Scintillation of Cerium Fluoride Through the Equilibrium and Photophysical Investigation of Cerium(III)-Fluoro Complexes

Thermodynamic and transport properties of the PrBr3–RbBr binary system

Contact Info

Product

Resources

About

Comparison of the spectroscopic behaviour of single crystals of lanthanide halides (X = Cl, Br)

Cited by 19 publications

References 23 publications

Rare-Earth Metal(III) Oxide Selenides M4O4Se[Se2] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

Rare-Earth Metal(III) Oxide Selenides M4O4Se[Se2] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

Explanation for the Multi-Component Scintillation of Cerium Fluoride Through the Equilibrium and Photophysical Investigation of Cerium(III)-Fluoro Complexes

Thermodynamic and transport properties of the PrBr3–RbBr binary system

Contact Info

Product

Resources

About

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties

Rare-Earth Metal(III) Oxide Selenides M₄O₄Se[Se₂] (M = La, Ce, Pr, Nd, Sm) with Discrete Diselenide Units: Crystal Structures, Magnetic Frustration, and Other Properties