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Artículos de revistas sobre el tema "Rare Earth Elements spectra"

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Publicado: 25 de mayo de 2024

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1

Suzuki, Chihiro, Fumihiro Koike, Izumi Murakami, Naoki Tamura, Shigeru Sudo y Gerry O’Sullivan. "Soft X-Ray Spectroscopy of Rare-Earth Elements in LHD Plasmas". Atoms 7, n.º 3 (3 de julio de 2019): 66. http://dx.doi.org/10.3390/atoms7030066.

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Soft X-ray spectra from high Z rare-earth (lanthanide) elements have been systematically observed in optically thin, high-temperature plasmas produced in the Large Helical Device (LHD), a facility for magnetically confined fusion research. It has been demonstrated that the discrete and quasicontinuum (UTA) spectral features from highly charged lanthanide ions are observed depending on the plasma temperature. The analyses of the measured spectra are ongoing by comparisons with theoretical calculations and/or previous experimental data available. The discrete spectra recorded in high-temperature conditions are dominated by individual lines of Ge- to Ni-like ions, while prominent peaks in the narrowed UTA spectra observed in low-temperature conditions are well explained by the transitions of Ag- to Rh-like ions.
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2

Koerting, Friederike, Nicole Koellner, Agnieszka Kuras, Nina Kristin Boesche, Christian Rogass, Christian Mielke, Kirsten Elger y Uwe Altenberger. "A solar optical hyperspectral library of rare-earth-bearing minerals, rare-earth oxide powders, copper-bearing minerals and Apliki mine surface samples". Earth System Science Data 13, n.º 3 (9 de marzo de 2021): 923–42. http://dx.doi.org/10.5194/essd-13-923-2021.

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Abstract. Mineral resource exploration and mining is an essential part of today's high-tech industry. Elements such as rare-earth elements (REEs) and copper are, therefore, in high demand. Modern exploration techniques from multiple platforms (e.g., spaceborne and airborne), to detect and map the spectral characteristics of the materials of interest, require spectral libraries as an essential reference. They include field and laboratory spectral information in combination with geochemical analyses for validation. Here, we present a collection of REE- and copper-related hyperspectral spectra with associated geochemical information. The libraries contain reflectance spectra from rare-earth element oxides, REE-bearing minerals, copper-bearing minerals and mine surface samples from the Apliki copper–gold–pyrite mine in the Republic of Cyprus. The samples were measured with the HySpex imaging spectrometers in the visible and near infrared (VNIR) and shortwave infrared (SWIR) range (400–2500 nm). The geochemical validation of each sample is provided with the reflectance spectra. The spectral libraries are openly available to assist future mineral mapping campaigns and laboratory spectroscopic analyses. The spectral libraries and corresponding geochemistry are published via GFZ Data Services with the following DOIs: https://doi.org/10.5880/GFZ.1.4.2019.004 (13 REE-bearing minerals and 16 oxide powders, Koerting et al., 2019a), https://doi.org/10.5880/GFZ.1.4.2019.003 (20 copper-bearing minerals, Koellner et al., 2019), and https://doi.org/10.5880/GFZ.1.4.2019.005 (37 copper-bearing surface material samples from the Apliki copper–gold–pyrite mine in Cyprus, Koerting et al., 2019b). All spectral libraries are united and comparable by the internally consistent method of hyperspectral data acquisition in the laboratory.
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3

Cowley, C. R. y M. Greenberg. "Third spectra of rare earth elements in chemically peculiar stars: IUE spectra". Monthly Notices of the Royal Astronomical Society 232, n.º 4 (1 de junio de 1988): 763–70. http://dx.doi.org/10.1093/mnras/232.4.763.

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4

Borisov, M. V., D. A. Bychkov, N. F. Pchelintseva y E. A. Ivleva. "Fractionation of rare-earth elements in the processes of hydrothermal ore formation". Moscow University Bulletin. Series 4. Geology, n.º 4 (28 de agosto de 2018): 59–64. http://dx.doi.org/10.33623/0579-9406-2018-4-59-64.

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Data on the distribution of elements across the Pb-Zn section of the Gatsyrovskaya vein (Upper Zgid, North Ossetia, Russia) showed that during the formation of the vein significant changes in the spectra of rare-earth elements (REE) occur in ore samples. The sharp growth of ratios LaN/YbN, LaN/NdN, GdN/HoN, and GdN/YbN is confined to the vein intervals, where the maximum amount of ore components is deposited. A comparison of the REE spectra of ores with the characteristics of the spectra of the near-vein and host rocks suggests that the deposition of the vein material occurred from solutions whose compositions with respect to the REE varied with time. REE fractionation occurred due to the mobilization of components by hydrothermal solutions during their reaction with the host Paleozoic granites.
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5

Gangrskiĭ, Yu P., S. G. Zemlyanoi, D. V. Karaivanov, N. N. Kolesnikov, K. P. Marinova, B. N. Markov y V. S. Rostovskii. "Hyperfine magnetic anomaly in the atomic spectra of rare-earth elements". Optics and Spectroscopy 92, n.º 5 (mayo de 2002): 658–63. http://dx.doi.org/10.1134/1.1481127.

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6

Choi, Sung Woo, Shuichi Emura, Shigeya Kimura, Moo Seong Kim, Yi Kai Zhou, Nobuaki Teraguchi, Akira Suzuki, Akira Yanase y Hajime Asahi. "Emission spectra from AlN and GaN doped with rare earth elements". Journal of Alloys and Compounds 408-412 (febrero de 2006): 717–20. http://dx.doi.org/10.1016/j.jallcom.2005.01.091.

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7

Afgan, Muhammad Sher, Zongyu Hou, Weiran Song, Jiachen Liu, Yuzhou Song, Weilun Gu y Zhe Wang. "On the Spectral Identification and Wavelength Dependence of Rare-Earth Ore Emission by Laser-Induced Breakdown Spectroscopy". Chemosensors 10, n.º 9 (25 de agosto de 2022): 350. http://dx.doi.org/10.3390/chemosensors10090350.

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The increasing demand for rare earth elements (REE) requires faster analysis techniques for their rapid exploration. Laser-induced breakdown spectroscopy (LIBS) has on-site and real time analysis capability. However, interference and the weaker emission of minor REEs are key challenges for the complex REE emission spectra. Using simulations and experimental results, we presented essential principles for improved line identification in the transient spectra of complicated samples, such as those of REE ores (e.g., monazite). Knowledge of plasma conditions, spectral collection setup, and capability of the spectral system are key parameters to consider for the identification of an emission line in such spectra. Furthermore, emission intensity dependence on laser wavelength was analyzed for major and minor REEs using IR (1064 nm), visible (532 nm) and UV (266 nm) irradiation. A higher plasma temperature was found with the IR laser, while stronger material ablation was observed by UV irradiation. Higher particle density by UV laser ablation was the key factor in the higher signal intensity of the minor elements, and this laser can improve the emission signals for LIBS use as an REE analyzer.
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8

Tepikina, Anna V. y Svetlana G. Vlasova. "Inorganic Composites Luminophors in Lithium-Borate Glasses with Rare-Earth Elements for White-Emitting Diodes". Defect and Diffusion Forum 410 (17 de agosto de 2021): 764–69. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.764.

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The paper describes the synthesis of novel luminescent composite system, based on lithium-borate glass matrix with addition of rare-earth elements and yttrium-aluminum garnet finely divided powder. The new chemical composition of glass has been selected, composite’s fabrication technology was developed, the temperature conditions of glass and luminophore sintering as well. The spectral characteristics of the obtained luminescent composites are measured, and chromaticity diagrams are considered. The radiation spectra showed a maximum of about 560 nm, the maximum spectral intensity of the radiation is about 90 μw/cm2/nm. Powerful energy saving source of white light was produced.
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9

Urakawa, R., W. Asano, M. Nishikawa, M. Kawahara, T. Nishi, D. Oshima, T. Kato y T. Ishibashi. "Magneto-optical property and magnetic anisotropy of (100) oriented R0.5Bi2.5Fe5O12 (R = Eu, Sm, and Pr) thin films prepared by metal–organic decomposition". AIP Advances 12, n.º 9 (1 de septiembre de 2022): 095322. http://dx.doi.org/10.1063/5.0094475.

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Bi-substituted rare-earth iron garnets, R3− xBi xFe5O12 (Bi:RIG), where R represents one of the rare-earth elements, exhibit the excellent magneto-optical (MO) properties that increase with Bi content x. In addition, magnetic properties of Bi:RIGs, such as the magnetization, the magnetic anisotropy, and the magnetostriction, could be controlled by choosing rare-earth elements. In this paper, we report on R0.5Bi2.5Fe5O12 (Bi2.5:RIG, R = Pr, Sm, and Eu) thin films on Gd3Ga5O12 (GGG) (100) single crystal substrates prepared by the metal–organic decomposition method. XRD analysis reveals that Bi2.5:RIG thin films are grown along the same orientation with GGG substrates, and their lattice constants are dependent on the ionic radii of the rare-earth ions. MO measurements show that Faraday spectra of the Bi2.5:RIG thin films have a typical spectral structure observed for Bi:RIGs. The magnetic anisotropy constants, the uniaxial magnetic anisotropy energy Ku, and the magnetocrystalline anisotropy energy K1 of Bi2.5:RIG (R = Y, Pr, Nd, Sm, and Eu) thin films are investigated by using the ferromagnetic resonance measurement.
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10

Huang, Zhaoqiang, Wenxuan Huang, Sheng Li, Bin Ni, Yalong Zhang, Mingwei Wang, Maolin Chen y Fuxiao Zhu. "Inversion Evaluation of Rare Earth Elements in Soil by Visible-Shortwave Infrared Spectroscopy". Remote Sensing 13, n.º 23 (1 de diciembre de 2021): 4886. http://dx.doi.org/10.3390/rs13234886.

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According to historical information, more than 300 metal smelting enterprises have been in the southwest of Xiongan for 300 years; however, these polluting enterprises have been gradually closed with the increased intensity of environmental protection. In the paper, 264 soil samples were collected and analyzed in the range of 400 nm–2500 nm by the spectra vista corporation (SVC), and the spectral noise was smoothed by the Savitzky–Golay filter. In order to enhance the spectral differences and curve shapes, mathematical transformations, such as the standard normal variate (SNV), first-order differential (FD), second-order differential (SD), multiple scattering correction (MSC), and continuum removal (CR), were performed on the data, and the correlation between spectral transformation and contents of REEs was analyzed. Moreover, three machine learning models—partial least-squares (PLS), random forest (RF), back propagation neural network (BPNN)—were used to predict the contents of REEs. Experimental results prove that REEs are combined with spectral active substances, such as organic compounds, clay minerals, and iron oxide, and it is possible to determine the contents of REEs using the reflection spectrum. The R2 between the predicted values and measured contents reached 0.986 by using BPNN after FD transformation. More importantly, the predicted values basically agree with the actual situation for CASI/SASI airborne hyperspectral images, and this is an effective technique to obtain the contents of REEs in soil at the study area.
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11

Ohiienko, O. V., S. V. Posmashnyi y T. V. Shvetz. "Investigation of the photoluminescence spectra of rare-earth elements in pores of an opal matrix". Journal of Physics and Electronics 26, n.º 2 (26 de diciembre de 2018): 67–72. http://dx.doi.org/10.15421/331827.

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The main idea of this paper is researching the light emission of Eu3+ and Dy3+ in an opal matrix. The opal synthesis was carried out using Stöber method. The size of globules calculated from the transmission spectrum of prepared samples is equal to 231 nm. The samples were infiltrated with rare-earth element oxides in concentrated solution of nitric HNO3 and perchloric HCl acids in the ratio 3:1. Next, the samples were heated to 100°C to reduce the relative content of water. The spectra of photoluminescence in the range 420-640 nm were excited by a semiconductor laser with λ=405 nm at the radiation registration along the direction of growth [111]. In the spectrum of the sample infiltrated by europium, there are distinctive europium lines at 580, 593 and 618 nm, which correspond to the typical transitions of this rare-earth element, such as 5D0→7F0, 5D0→7F1 and 5D0→7F2. Distinctive spectral lines of dysprosium luminescence are at wavelengths of 480 and 572 nm. The maxima of these wavelengths correspond to the typical lines of luminescence of trivalent dysprosium – specifically, transitions 4D9/2→6H13/2 and 4D9/2→6H11/2. The influence of photonic crystalline effects on the photoluminescence spectra of the obtained samples is studied.
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12

Kumari, Aarti, Kamala Kanta Sahu y Sushanta Kumar Sahu. "Solvent Extraction and Separation of Nd, Pr and Dy from Leach Liquor of Waste NdFeB Magnet Using the Nitrate Form of Mextral® 336At in the Presence of Aquo-Complexing Agent EDTA". Metals 9, n.º 2 (25 de febrero de 2019): 269. http://dx.doi.org/10.3390/met9020269.

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：Solvent extraction and separation of Pr, Nd and Dy from a synthetic leach solution of spent NdFeB magnet from wind turbines in the presence of aquo-complexing agent Ethylenediaminetetraacetic acid (EDTA) was studied using the nitrate form of Mextral® 336At ([336At][NO3]) as an extractant. The effect of different process parameters such as pH, extractant, nitrate, and EDTA concentrations on the extraction of Pr, Nd and Dy was studied. The extraction of these rare earths elements follows the order Pr > Nd > Dy, whereas EDTA forms stable complexes in the order Dy > Nd > Pr. The synergy of these two effects improved the selectivity among these elements as compared to when no aquo-complexing agent was used. The mechanism of extraction of rare earth elements was established by slope analysis method. The Fourier-Transform Infrared Spectroscopy (FTIR) spectra of [336At][NO3] and extracted Nd complex were recorded to understand the interaction of extractant with rare earth metal ions in the organic phase.
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13

Ivanova, O. S., I. S. Edelman, R. D. Ivantsov, V. Zabluda, V. Zaikovskiy y S. Stepanov. "Nanostructures Based on Glasses Doped with 3d and 4f Elements". Solid State Phenomena 152-153 (abril de 2009): 221–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.152-153.221.

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Nano-composite structures based on potassium-aluminum-germanium glasses doped simultaneously with Fe and rare earth (RE) oxides - Gd, Tb, Dy, Ho, or Yb were studied for the first time. Samples were fabricated by glass technology and subjected to an additional thermal treatment at different regimes. Formation of magnetic nanoparticles was revealed with transmission electron microscope. Morphology and space distribution of nanoparticles in the glasses as well as optical and magneto optical spectra have been shown to be dependent on the additional treatment regime and almost independent of the type of the rare earth element.
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14

Naldrett, D. L., Andre Lachaine y S. N. Naldrett. "Rare-earth elements, thermal history, and the colour of natural fluorites". Canadian Journal of Earth Sciences 24, n.º 10 (1 de octubre de 1987): 2082–88. http://dx.doi.org/10.1139/e87-197.

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The contents of La and of all 13 naturally occurring rare-earth elements (REEs) in samples of natural fluorites were determined by neutron activation analysis. The samples were chosen to test the relation of REE content to colour. Total REE contents of the samples ranged from 3.46 to 97.2 ppm; the range of the least abundant REE, Lu, was 0.031–0.57 ppm and the range of the most abundant REE, Ce, was 0.94–33.3 ppm. No relation was found between the absolute amounts nor the enrichment or depletion of a particular REE and colour. The absorption spectra from 400 to 700 nm were determined by photo-acoustic spectroscopy using a few milligrams of powdered fluorite sample. Optical absorption spectra were obtained for all samples including those that were too small or too opaque for transmission or reflectance methods. The absorption maxima obtained are similar to those reported by others for samples of similar colours. It is concluded that ionizing radiations from incorporated radioactive elements produce the divalent REE ions that account initially for purple colour. From the description given in the literature on the thermoluminescence of fluorites it is then shown that the thermal history can account for the ultimate colour. However, other factors, such as the presence of water vapour, oxygen, or hydrogen; variation in the growth rate of crystals; colloidal particles; and exposure to light, can contribute to the colour.
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15

Gaft, M., G. Panczer, E. Uspensky y R. Reisfeld. "Laser-induced time-resolved luminescence of rare-earth elements in scheelite". Mineralogical Magazine 63, n.º 2 (abril de 1999): 199–210. http://dx.doi.org/10.1180/002646199548439.

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AbstractNatural and synthetic scheelite are investigated by time-resolved laser-induced luminescence to detect and ascribe various luminescence lines to a variety of REE. The selectivity of detection is possible by using different time delays after excitation, different gate widths and different excitation wavenumbers and allowed to detect REE in samples where they are hidden by intrinsic luminescence and not visible in the steady-state spectra as well as by cathodoluminescenee. Luminescence of Pr3+, Er3+ and Tm3+ are detected even with low concentrations and in the presence of Tb3+, Dy3+ and Sm3+. Luminescence of Ho3+ and Yb3+ is firstly detected in natural scheelites and luminescence of Eu2+ and Ce3+ is preliminary suggested.
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16

Dellith, Jan y Michael Wendt. "The M emission spectra of the heavy rare earth elements 67 ≤ Z ≤ 71". Microchimica Acta 161, n.º 3-4 (14 de diciembre de 2007): 475–78. http://dx.doi.org/10.1007/s00604-007-0873-1.

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17

Fuchs, Margret C., Jan Beyer, Sandra Lorenz, Suchinder Sharma, Axel D. Renno, Johannes Heitmann y Richard Gloaguen. "A spectral library for laser-induced fluorescence analysis as a tool for rare earth element identification". Earth System Science Data 13, n.º 9 (14 de septiembre de 2021): 4465–83. http://dx.doi.org/10.5194/essd-13-4465-2021.

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Abstract. With the recurring interest in rare earth elements (REEs), laser-induced fluorescence (LiF) may provide a powerful tool for their rapid and accurate identification at different stages along their value chain. Applications to natural materials such as minerals and rocks could complement the spectroscopy-based toolkit for innovative, non-invasive exploration technologies. However, the diagnostic assignment of detected emission lines to individual REEs remains challenging because of the complex composition of natural rocks in which they can be found. The resulting mixed spectra and the large amount of data generated demand automated approaches of data evaluation, especially in mapping applications such as drill core scanning. LiF reference data provide the solution for robust REE identification, yet they usually remain in the form of tables of published emission lines. We show that a complete reference spectra library could open manifold options for innovative automated analysis. We present a library of high-resolution LiF reference spectra using the Smithsonian rare earth phosphate standards for electron microprobe analysis. We employ three standard laser wavelengths (325, 442, 532 nm) to record representative spectra in the UV-visible to near-infrared spectral range (340–1080 nm). Excitation at all three laser wavelengths yielded characteristic spectra with distinct REE-related emission lines for EuPO4, TbPO4, DyPO4 and YbPO4. In the other samples, the high-energy excitation at 325 nm caused unspecific, broad-band defect emissions. Here, lower-energy laser excitation is shown to be successful for suppressing non-REE-related emission. At 442 nm excitation, REE reference spectra depict the diagnostic emission lines of PrPO4, SmPO4 and ErPO4. For NdPO4 and HoPO4 the most efficient excitation was achieved with 532 nm. Our results emphasise the possibility of selective REE excitation by changing the excitation wavelength according to the suitable conditions for individual REEs. Our reference spectra provide a database for the transparent and reproducible evaluation of REE-bearing rocks. The LiF spectral library is available at zenodo.org and the registered DOI https://doi.org/10.5281/zenodo.4054606 (Fuchs et al., 2020). Primarily addressing the raw material exploration sector, it aids particularly the development of advanced data processing routines for LiF analysis but can also support further research on the REE luminescence in natural rocks or artificial compounds. It gives access to traceable data for the comparison of emission line positions, emission line intensity ratios and splitting into emission line sub-levels or can be used as reference or training data for automated approaches of component assignment.
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18

Grigoryeva, A. V., A. V. Volkov y K. Y. Murashov. "Rare-earth elements in Cu-Ni ores of the Norilsk region". Arctic: Ecology and Economy 11, n.º 1 (marzo de 2021): 76–89. http://dx.doi.org/10.25283/2223-4594-2021-1-76-89.

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The deposits of the Norilsk region are confined to the marginal northwestern part of the Siberian platform and are associated with the manifestation of the Early Mesozoic trap volcanism. Sulfide mineralization is concentrated in the intrusive facies of the volcano-intrusive complex. Four main types of Cu-Ni ores are distinguished according to textural features: massive, vein-disseminated, brecciated, and disseminated. The main types of Cu-Ni ores differ significantly from each other in the chemical composition and content of rock- and ore-forming components. The enrichment ratios of ore trace elements in the Oktyabrskaya and Talnakhskaya vein-disseminated ore mainly reach hundreds (S, Pt, Au, Se,Te, Pb, As, Sn, Mo) and thousands (Ni, Cu, Ag, Pd) times. A rather high enrichment of all types of Bi, Re and Cd ores has been revealed, which are potentially industrially significant as high-tech metals, and can be promising for associated mining. The amount of rare-earth elements (REE) in ores is several times less than in the upper crust and more than in the primitive mantle. The concentration of rare earths in the main types of ores, with the exception of massive ones, exceeds the level of the chondrite standard, and REE fractionation is weak. The distribution spectra of chondrite-normalized REEs have a slight negative slope: the total content of light REEs is higher than that of heavy ones. The similarity of the geometry of the REE spectra of massive, vein-disseminated, brecciated and disseminated types of ores containing a significant admixture of host rocks indicates the inheritance of the REE composition in ores from the host rocks. In the disseminated ores of common taxite gabbro-dolerites, the Eu anomaly is present in the Kharaelakhsky (Oktyabrskoye Deposit) and Talnakhsky (Talnakhskoye Deposit) intrusions, it is positive, and in the Norilsk I Intrusive (in the same rocks), it is negative. Higher concentrations of REEs and significant fractionation of light and heavy rare elements are typical for host contact-metamorphic and metasomatic rocks with vein-disseminated (exocontact) ores. For olivine-free hornfels and skarns in brecciated ores, as well as for vein-disseminated ores, significant fractionation of light REEs with relatively heavy ones and a pronounced Eu minimum are characteristic. In massive ores, the distribution of REEs is determined by the composition of xenoliths.
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19

Boumans, P. W. J. M. y A. H. M. Van Ham-Heijms. "Simulation of atomic spectra—II. Mutual spectral interferences of rare earth elements in the inductively coupled plasma". Spectrochimica Acta Part B: Atomic Spectroscopy 46, n.º 14 (enero de 1991): 1863–83. http://dx.doi.org/10.1016/0584-8547(91)80211-k.

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20

Djabbarov, I., M. K. Salakhitdinova y A. A. Yusupov. "INFLUENCE OF RARE-EARTH ELEMENTS AND RADIATION ON SPECTRAL PROPERTIES AND THERMAL CONDUCTIVITY OF YTTRIUM-ALUMINUM GARNETS AND PHOSPHATE GLASSES". Materials Science, n.º 10 (21 de octubre de 2022): 3–8. http://dx.doi.org/10.31044/1684-579x-2022-0-10-3-8.

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The experimental results of radiation-optical studies of yttrium-aluminum garnet (YAG) crystals, non-activated and activated by rare earth ions (Y3Al5O12—TR3+), as well as phosphate glasses activated by Nd3+ ions are presented. It is shown that the main mechanisms of phonon scattering on point defects play a role in changing the radio- and thermoluminescence spectra. Keywords: radiation-optical, phosphate glass, impurity, rare-earth element, yttrium-aluminum garnet, point defect, thermoluminescence.
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21

Gaurkhede, S. G., M. M. Khandpekar, S. P. Pati y A. T. Singh. "Blue Fluorescence in Doped LaF3 Nanocrystals Synthesized by Microwave Technique". Advanced Materials Research 584 (octubre de 2012): 219–23. http://dx.doi.org/10.4028/www.scientific.net/amr.584.219.

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Hexagonal-phase LaF3: Ce3+, Pr3+, and Sm3+ doped (LCPS) nano-crystals have been synthesized by keeping same molarities of rare earth elements using aqueous route. The samples have been synthesized in conventional microwave on low power range in about an hour’s time. The phase formation has been verified by powder X-ray diffraction (XRD).Hexagonal geometry of the LCPS nano-crystals has been observed with an average particle size of 20 nm by TEM analysis. The JCPDS Card No. (32-0483) and selected area electron diffraction (SAED) pattern has been used for identification of crystal structure. The UV- VIS spectra indicated band gap of 5.00eV. The FTIR spectrums have been used for assignment of fundamental vibrations. Blue fluorescence observed with exciting wavelengths of 254 nm respectively. The presence of rare-earth elements in LCPS nano-crystals have been verified by the EDAX spectra.
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22

Etz, Edgar S. y Douglas H. Blackburn. "Rare-earth fluorescence in Raman microprobe spectra of glasses and ceramics". Proceedings, annual meeting, Electron Microscopy Society of America 50, n.º 2 (agosto de 1992): 1540–41. http://dx.doi.org/10.1017/s0424820100132339.

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We are reporting on spectroscopic observations, made with the Raman microprobe, of fluorescence emissions by several rare earth, or lanthanide ions (Ln3+), in several types of ordered and disordered solids. These studies are an extension of earlier work on the luminescence properties of mainly two ions, Eu3+ and Er3+, as components of silicate glasses and of various ceramics related to high-temperature superconducting systems. Concerning the Y-Ba-Cu-O system, where yttrium has been replaced by one of the lanthanide elements (Ln = Nd, Sm, Eu, Dy, Ho, Er), our aim is to relate the observed optical spectra (Raman and fluorescence) to the composition and structure of the solids derived from the phase diagram. For this system, the Raman spectra of most of the compounds are well understood. Much less is known about the fluorescence spectra of the rare-earth substituted analogs and their relation to composition and structural order. The luminescence emissions of many of the Ln3+ ions can serve as useful spectroscopic probes of the structure of the host compound, of differences in bonding, and in the charge environment.
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23

Matsuda, Motofumi y Keisuke Ohto. "Improved Adsorption Capacity of EDTA-type Chitosan for Separation of Rare Earths". MATEC Web of Conferences 333 (2021): 04005. http://dx.doi.org/10.1051/matecconf/202133304005.

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By optimizing the raw material ratio for the preparation of ethylenediaminetetraacetic acid-type chitosan (EDTA-type chitosan), the extraction efficiency of rare earth elements was improved. The synthesis with a lower concentration ratio of chitosan to acetic acid than that in the previously reported preparation method was confirmed by IR spectra that the peak assigned as the carboxyl group of EDTA was drastically decreased and the amide bond reaction between chitosan and EDTA was more facilitated. In the preparation method of this work, the amide formation was preferable to the competitive acetylation of chitosan. By the optimizing preparation conditions, the adsorption capacities for Nd, Sm, Tb, and Dy were improved about twice. On the contrary, the separation factor of rare earths was not changed, and it is suggested that other compounds having adsorption ability were not produced. EDTA-type chitosan was applied to chromatographic separation of La, Nd, Sm, Tb, and Dy. In the column method, it was confirmed that lighter rare earth sequentially eluted from the column, therefore it has been proved that adsorption of lighter rare earth was substituted by heavier rare earth.
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24

Matsuda, Motofumi y Keisuke Ohto. "Improved Adsorption Capacity of EDTA-type Chitosan for Separation of Rare Earths". MATEC Web of Conferences 333 (2021): 04005. http://dx.doi.org/10.1051/matecconf/202133304005.

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By optimizing the raw material ratio for the preparation of ethylenediaminetetraacetic acid-type chitosan (EDTA-type chitosan), the extraction efficiency of rare earth elements was improved. The synthesis with a lower concentration ratio of chitosan to acetic acid than that in the previously reported preparation method was confirmed by IR spectra that the peak assigned as the carboxyl group of EDTA was drastically decreased and the amide bond reaction between chitosan and EDTA was more facilitated. In the preparation method of this work, the amide formation was preferable to the competitive acetylation of chitosan. By the optimizing preparation conditions, the adsorption capacities for Nd, Sm, Tb, and Dy were improved about twice. On the contrary, the separation factor of rare earths was not changed, and it is suggested that other compounds having adsorption ability were not produced. EDTA-type chitosan was applied to chromatographic separation of La, Nd, Sm, Tb, and Dy. In the column method, it was confirmed that lighter rare earth sequentially eluted from the column, therefore it has been proved that adsorption of lighter rare earth was substituted by heavier rare earth.
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25

Imashuku, Susumu, Kazuaki Wagatsuma y Jun Kawai. "Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets". Microscopy and Microanalysis 22, n.º 1 (7 de enero de 2016): 82–86. http://dx.doi.org/10.1017/s1431927615015676.

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AbstractScanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium–iron–boron (NdFeB) and samarium–cobalt (Sm–Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm–Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.
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26

Zhang, Chuting, Chaoyang Chen, Zhibin Li y Andy H. Shen. "Chemical Composition and Spectroscopic Characteristics of Alexandrite Effect Apatite from the Akzhailyau Mountains of Kazakhstan". Minerals 13, n.º 9 (28 de agosto de 2023): 1139. http://dx.doi.org/10.3390/min13091139.

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The alexandrite effect is a pivotal optical phenomenon in gemmology, evident in several notable gemstones. However, the manifestation of this effect in apatite from Kazakhstan stands out as both rare and highly sought after. This apatite displays a yellowish-green hue in daylight and transitions to a pinkish-orange shade under incandescent lighting. This research involved analyzing the apatite’s chemical composition using LA-ICP-MS, in addition to obtaining its infrared, Raman, UV-Vis, and fluorescence spectra. From the elemental assessment results, the primary trace elements in the apatite were identified as Na, Mn, and Fe, along with rare-earth elements including Gd, Dy, Ce, Nd, and Sm. The infrared and Raman spectra showcased peaks corresponding to phosphate and hydroxyl groups. The apatite’s alexandrite effect predominantly stems from absorption peaks at 748, 738, 583, 578, and 526 nm in the visible spectrum, all of which are attributed to the rare-earth element, Nd. The fluorescence peaks of the apatite are primarily influenced by elements such as Ce, Eu, Nd, and Mn. Through this research, a theoretical foundation has been laid for the non-destructive identification of apatite exhibiting the alexandrite effect.
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27

Gritsenko, Yu D. y A. A. Serova. "Minerals-concentrators of rare-earth elements in basites-ultrabasites intrusives of Norilsk district". Proceedings of higher educational establishments. Geology and Exploration, n.º 3 (28 de junio de 2017): 56–65. http://dx.doi.org/10.32454/0016-7762-2017-3-56-65.

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The conditions of being, the history of formation and transformation of minerals-concentrators of rare-earth elements (REE) - apatite minerals group and epidote minerals group, have been studied and described. Allanite has been determined to be mostly developed in the halos of the fluid action a solid contact of sulfide ores containing rich pneu matolytic mineralization of the platinum-group elements (PGM) and gold. Apatite and allanite are found among sulfides and in rims of the fluid action over the drops of sulphides in the horizon of the disseminated ores. The composition of Apatite-I has evolved from a OH-containing chlorapatite to chlorapatite containing up to 2,3 wt. % of lanthanides; Apatite-II - from OH-Cl-bearing fluorapatite to fluorapatite. The lanthanides reieased during replacement of chlorapatite-I by fluorapatite-II, probably entering the composition of the produced pneumatoiytic alianite-(Ce). In the areas of mineral ores with imposed metamorphism, the pneumatoiytic apatite partially or totally is substituted by hydroxyapatite-III, allanite - by water-containing allanite with the content of the epidote and clinozoisite minals - 30-35 mol. %. The spectra of REE distribution in apatite have been determined to reflect more accurately their ratios in rocks, the spectra of REE distribution for allanite are characterized by a steeper slope from lighter to heavier lanthanides. The ratio of La, Ce and Nd in chlorapatite corresponds to the distribution of these elements as in the host picrite horizon, as well in the rocks of the intrusives as a whole. Allanite, in return, is more enriched in cerium and lanthanum and depleted in neodymium.
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28

Fernandez-Cortes, Angel, Soledad Cuezva, Elena Garcia-Anton, Javier Garcia-Guinea y Sergio Sanchez-Moral. "Rare Earth Elements in a Speleothem Analyzed by ICP-MS, EDS, and Spectra Cathodoluminescence". Spectroscopy Letters 44, n.º 7-8 (octubre de 2011): 474–79. http://dx.doi.org/10.1080/00387010.2011.610403.

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29

Batyaev, I. M., R. Yu Gasanov y O. V. Gasanova. "Computer processing of electronic absorption spectra of rare-earth elements in inorganic laser media". Optics and Spectroscopy 97, n.º 1 (julio de 2004): 48–49. http://dx.doi.org/10.1134/1.1781280.

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30

Borst, Anouk M., Adrian A. Finch, Henrik Friis, Nicola J. Horsburgh, Platon N. Gamaletsos, Joerg Goettlicher, Ralph Steininger y Kalotina Geraki. "Structural state of rare earth elements in eudialyte-group minerals". Mineralogical Magazine 84, n.º 1 (2 de agosto de 2019): 19–34. http://dx.doi.org/10.1180/mgm.2019.50.

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AbstractEudialyte-group minerals (EGM) attract global interest as potential resources for high-field-strength elements (e.g. Zr, Nb, Ta, and rare-earth elements), i.e. critical materials for modern technologies. They are particularly valued for their relative enrichment in the most critical lanthanides, i.e. Nd and heavy rare earth elements (Gd–Lu). However, rare earth element (REE) substitution mechanisms into the EGM structure are still poorly understood. Light and heavy REE may occupy different sites and there may be ordering and/or defect clustering in the structure. This study uses X-ray absorption spectroscopy to determine the structural state of REE in EGM from prospective eudialyte-bearing complexes. Yttrium K-edge and Nd L3-edge spectra were collected as proxies for heavy and light REE, respectively, and compared to natural and synthetic REE-bearing standards. Extended X-ray absorption fine structure data yield best fits for Y in six-fold coordination with Y–O distances of 2.24–2.32 Å, and a second coordination sphere comprising Fe, Na, Ca, Si and O at radial distances of 3.6–3.8 Å. These findings are consistent with dominant Y3+ substitution for Ca2+ on the octahedral M1 site in all the samples studied, and exclude preferential substitution of Y3+ onto the smaller octahedral Z site or the large low-symmetry N4 site.Using lattice strain theory, we constructed relative partitioning models to predict site preferences of lanthanides we have not measured directly. The models predict that all REE are favoured on the Ca-dominant M1 site and that preferential partitioning of heavy over light REE increases in EGM containing significant Mn in the M1-octahedral rings (oneillite subgroup). Thus, the flat REE profiles that make EGM such attractive exploration targets are not due to preferential partitioning of light and heavy REE onto different sites. Instead, local ordering of Mn- and Ca-occupied M1 sites may influence the capacity of EGM to accommodate heavy REE.
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31

Nguyen Thi Hien, Lan y Loan Nguyen Thi To. "Synthesis, properties, luminescence of mixed ligands complexes of acetylsalicylate and 1,10-phenantroline with some light rare earth elements". Vietnam Journal of Catalysis and Adsorption 10, n.º 1S (15 de octubre de 2021): 366–72. http://dx.doi.org/10.51316/jca.2021.134.

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Mixed ligands complexes of acetylsalicylic and 1,10-phenantroline of Ln(III) with the general formula Ln(AcSa)3(Phen).3H2O (Ln: Nd, Sm, Eu; AcSa-: Acetylsalicylate, Phen: 1,10-phenantroline) have been prepared. The characterization of these complexes have been studied by IR, thermal analysis and mass-spectroscopy methods; The luminescence of complexes was investigated by measuring the excitation and emission spectra. IR spectra suggest that complexes have been synthesised successfully. Mass-spectroscopy showed that the complexes are monomes and they are stable. The intramolecular ligand-to-rare earth energy transfer mechanisms were discussed. The emission spectra of Eu(AcSa)3(Phen).3H2O consist of the 5D0 → 7F2 and 5D0 → 7F1 dominant transitions located at 614 nm and 593 nm, the weaker 5D0 → 7F4 transition located at 699 nm, the weakest 5D0 → 7F3 transition located at 654 nm. The emission spectra of the Sm(AcSa)3(Phen).3H2O displayed three bands, in there, the 4G5/2 – 6H7/2 and 4G5/2 – 6H9/2 equivalent transitions located at 599 nm and 645 nm, the weakest 4G5/2 – 6H5/2 transition located at 564 nm. The emission spectra of the Nd(AcSa)3Phen.3H2O displayed one band at 440 nm, i.e. 4F3/2 – 4I9/2 energy level of Nd3+ was observed. These complexes showed room-temperature photoluminescence
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32

Kolesov, B. A. y I. G. Vasil'eva. "Raman spectra and structural characteristics of rare-earth element disulfides". Journal of Structural Chemistry 33, n.º 4 (1993): 531–35. http://dx.doi.org/10.1007/bf00746930.

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33

Leapman, R. D. y D. E. Newbury. "Trace analysis of transition elements and rare earths by parallel EELS". Proceedings, annual meeting, Electron Microscopy Society of America 50, n.º 2 (agosto de 1992): 1250–51. http://dx.doi.org/10.1017/s0424820100130882.

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It has been realized for some years that electron energy loss spectroscopy (EELS) offers the potential for a highly sensitive microanalytical technique. Here, we present measurements from some NIST glass standard reference materials showing that EELS provides both high spatial resolution and trace sensitivity for a wide range of elements including the 3-d transition metals and the lanthanides.Specimens were prepared by grinding the glass and depositing the powder on to thin carbon support films. The energy loss spectra were collected by means of a Gatan 666 parallel-detection spectrometer attached to a VG Microscopes HB501 scanning transmission electron microscope (STEM) operating at 100 keV beam energy. This arrangement gave an energy resolution of approximately 0.4 eV limited by the spread of the field-emission source. Large spectral intensities were obtained by setting the probe current to about 8 nA and the collection semi-angle to 20 mrad. In order to eliminate possible hydrocarbon contamination the specimens were cooled to -160 C.
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34

MacRae, Colin M., Nicholas C. Wilson y Joel Brugger. "Quantitative Cathodoluminescence Mapping with Application to a Kalgoorlie Scheelite". Microscopy and Microanalysis 15, n.º 3 (22 de mayo de 2009): 222–30. http://dx.doi.org/10.1017/s1431927609090308.

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AbstractA method for the analysis of cathodoluminescence spectra is described that enables quantitative trace-element-level distributions to be mapped within minerals and materials. Cathodoluminescence intensities for a number of rare earth elements are determined by Gaussian peak fitting, and these intensities show positive correlation with independently measured concentrations down to parts per million levels. The ability to quantify cathodoluminescence spectra provides a powerful tool to determine both trace element abundances and charge state, while major elemental levels can be determined using more traditional X-ray spectrometry. To illustrate the approach, a scheelite from Kalgoorlie, Western Australia, is hyperspectrally mapped and the cathodoluminescence is calibrated against microanalyses collected using a laser ablation inductively coupled plasma mass spectrometer. Trace element maps show micron scale zoning for the rare earth elements Sm3+, Dy3+, Er3+, and Eu3+/Eu2+. The distribution of Eu2+/Eu3+ suggests that both valences of Eu have been preserved in the scheelite since its crystallization 1.63 billion years ago.
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35

MacRae, C. M., N. C. Wilson, A. Torpy y C. J. Davidson. "Hyperspectral Cathodoluminescence Imaging and Analysis Extending from Ultraviolet to Near Infrared". Microscopy and Microanalysis 18, n.º 6 (20 de noviembre de 2012): 1239–45. http://dx.doi.org/10.1017/s1431927612013505.

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AbstractThe measurement of near-infrared (NIR) cathodoluminescence (CL) with sufficient sensitivity to allow full spectral mapping has been investigated through the application of optimized grating spectrometers that allow the ultraviolet (UV), visible, and NIR CL spectra to be measured simultaneously. Two optical spectrometers have been integrated into an electron microprobe, allowing simultaneous collection of hyperspectral CL (UV-NIR), characteristic X-rays, and electron signals. Combined hyperspectral CL spectra collected from two natural apatite (Ca5[PO4]3[OH,F]) samples from Wilberforce (Ontario, Canada) and Durango (Mexico) were qualitatively analyzed to identify the emission centers and then deconvoluted pixel-by-pixel using least-squares fitting to produce a series of ion-resolved CL intensity maps. Preliminary investigation of apatite has shown strong NIR emissions associated primarily with the rare-earth element Nd. Details of growth and alteration were revealed in the NIR that were not discernable with electron-induced X-ray mapping. Intense emission centers from Nd3+ and Sm3+ were observed in the spectra from both apatites, along with minor emissions from other 3+ rare-earth elements. Quantitative electron probe microanalysis was performed on points within the mapped area of the Durango apatite to produce a calibration line relating cathodoluminescent intensity of the fitted peak centered at 1,073 nm (1.156 eV) to the Nd concentration.
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36

LOO, B. H., D. H. BURNS y A. L. XIDIS. "A RAMAN SPECTROSCOPIC STUDY OF RE2BaCuO5 WHERE RE = Y, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Lu". Modern Physics Letters B 03, n.º 18 (diciembre de 1989): 1401–7. http://dx.doi.org/10.1142/s0217984989002107.

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We have prepared and determined the Raman spectra of a class of compounds of formula RE2 BaCuO 5, where RE = Y , Sm, Eu, Gd, Dy, Ho, Er, Tm, and Lu. Other rare-earth elements, Nd, Ce, Tb and Pr, are found not to form this class of compounds.
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37

Tchang-Brillet, W. Ü. Lydia, Ali Meftah, Djamel Deghiche, Jean-François Wyart, Christian Balança, Norbert Champion y Christophe Blaess. "Laboratory studies of Vacuum Ultra-Violet (VUV) emission spectra of heavy element ions". Proceedings of the International Astronomical Union 15, S357 (octubre de 2019): 84–88. http://dx.doi.org/10.1017/s1743921320000307.

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AbstractReliable spectroscopic data are needed for interpretation and modeling of observed astrophysical plasmas. For heavy element ions, which have complex spectra, experimental data are rather incomplete. To provide valuable fundamental quantities, such as precise wavelengths, level energies and semi-empirical transition probabilities, we are carrying out laboratory studies of high-resolution VUV emission spectra of moderately charged ions of transition metals and rare earth elements. Experimental and theoretical methods are summarized. Examples of studies are described.
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38

Martin, Madhavi, Daniel Hamm, Samir Martin, Steve Allman, Gary Bell y Rodger Martin. "Micro-Laser-Induced Breakdown Spectroscopy: A Novel Approach Used in the Detection of Six Rare Earths and One Transition Metal". Minerals 9, n.º 2 (12 de febrero de 2019): 103. http://dx.doi.org/10.3390/min9020103.

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Laser-induced breakdown spectroscopy (LIBS) was undertaken using an instrument which used a high-powered microscope to deliver the light and tightly focused the low energy laser beam onto the surface of a solid sample. A micro-plasma was generated on the surface of the sample under test even though the amount of energy/pulse from a beam of 532 nm was <1 mJ. Rare earth elements such as europium, gadolinium, lanthanum, neodymium, praseodymium, samarium, and a transition metal, yttrium, were tested. These elements are important in nuclear fission reactions especially for estimation of actinide masses for non-proliferation “safeguards”. Each element was mixed in the graphite matrix in different percentages from 1% to 50% by weight and the LIBS spectra were obtained for each composition as well as after mixing each element in the same amount using oxides of the elements. The data for the 5% mixture of the rare earth elements with graphite powder along with the transition metal has been presented in this article. A micro-LIBS approach was used to demonstrate that these rare earth elements can be identified individually and in a complex mixture in glove boxes in which the microscope LIBS instrument is housed in a nuclear research environment.
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39

Vallejo, M. A., S. Romero-Servin, Moisés I. Casillas Alvarez, Janet A. Elias Angel, C. Gomez-Solis, Leonardo Álvarez-Valtierra y M. A. Sosa. "Enhancing the Nonlinear Optical Properties of Lithium Tetraborate Glass Using Rare Earth Elements and Silver Nanoparticles". Nano 15, n.º 05 (mayo de 2020): 2050064. http://dx.doi.org/10.1142/s1793292020500642.

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In recent years, nonlinear optics field is in constant growth, particularly on the characterization and study of optical properties of glass compounds. In this sense, the plasmonic effect caused by silver nanoparticles (SNP) on the nonlinear optical (NLO) properties of different materials was studied. Furthermore, we report the experimental absorption spectra, the emission spectra, Z-scan measurements in both closed and open apertures and scanning transmission electron microscopy (STEM) to show the morphology of the matrices and the nucleation of SNP. Moreover, some NLO parameters were calculated, such as the NL refraction index and NL coefficient absorption of lithium tetraborate (Li2B4O7) glass activated with rare earths (Dy3+ and Yb3+), as well as study of the effect of different concentrations of SNP. From the results obtained, it has been ascertained that the plasmon resonance caused by the presence of SNP enhances the NL refraction index value, as well as most of its linear optical properties in the matrix of Li2B4O7.
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40

Bhatt, Chet R., Jinesh C. Jain, Christian L. Goueguel, Dustin L. McIntyre y Jagdish P. Singh. "Determination of Rare Earth Elements in Geological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS)". Applied Spectroscopy 72, n.º 1 (24 de octubre de 2017): 114–21. http://dx.doi.org/10.1177/0003702817734854.

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Laser-induced breakdown spectroscopy (LIBS) was used to detect rare earth elements (REEs) in natural geological samples. Low and high intensity emission lines of Ce, La, Nd, Y, Pr, Sm, Eu, Gd, and Dy were identified in the spectra recorded from the samples to claim the presence of these REEs. Multivariate analysis was executed by developing partial least squares regression (PLS-R) models for the quantification of Ce, La, and Nd. Analysis of unknown samples indicated that the prediction results of these samples were found comparable to those obtained by inductively coupled plasma mass spectrometry analysis. Data support that LIBS has potential to quantify REEs in geological minerals/ores.
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41

Bueno, Patricia, Maria Esther Sbampato, José Wilson Neri, Luiz Felipe Nardin Barreta, Jhonatha Ricardo Dos Santos, Alessandro Rogério Victor y Marcelo Geraldo Destro. "ESPECTROSCOPIA OPTOGALVÂNICA DE ÉRBIO OPTOGALVANIC SPECTROSCOPY OF ERBIUM". Eclética Química Journal 38, n.º 1 (25 de octubre de 2017): 85. http://dx.doi.org/10.26850/1678-4618eqj.v38.1.2013.p85-89.

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The rare earth elements have been creating a large interest due to their applications in several areas of science and technology. This paper presents some spectra obtained by the optogalvanic spectroscopy technique with an erbium hollow cathode lamp, in order to gather information about the atom, necessary for the isotope separation.
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42

Черемисина, О. В. y Е. С. Лукьянцева. "THE DILUENT’S ROLE IN THE EXTRACTION OF RARE EARTH ELEMENTS". Южно-Сибирский научный вестник, n.º 3(49) (30 de junio de 2023): 100–107. http://dx.doi.org/10.25699/sssb.2023.49.3.005.

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Редкоземельные элементы — критически важные для наукоёмких технологий металлы, на территории России содержащиеся главным образом в апатите. Фосфорная кислота, образующаяся при его разложении, имеет огромный потенциал как сырьё для их побочного получения и в представленной статье стала объектом исследований. В работе рассмотрено извлечение редкоземельных элементов на примере эрбия и иттербия из фосфорнокислых растворов методом жидкостной экстракции ди-2-этилгексилфосфорной кислотой. Процесс экстракции существенно зависит как от самого экстрагента, так и от разбавителя, состав и физико-химические свойства которого непосредственно влияют на ключевые показатели эффективности экстракции: степень извлечения, коэффициенты распределения и разделения, стойкость образующейся эмульсии и время разделения водной и органической фаз. В статье проводится сравнение трёх видов разбавителей: традиционно использующегося керосина и алифатических разбавителей Elixore 205 и Isane Biolife 58 производства TotalEnergies. Выявлено значительное улучшение экстракции при использовании смеси экстрагента с разбавителями TotalEnergies по сравнению с керосином. Наилучшее извлечение эрбия наблюдается при использовании разбавителя Isane Biolife 58: соотношение Vэкстрагент:Vразбавитель = 1:10 обеспечивает извлечение в 1,5–2 раза выше, чем при использовании керосина, а степень извлечения в 80 % достигается при соотношении 1:4, при котором в случае с керосином степень извлечения составляет 65 %. Коэффициент разделения эрбия и иттербия при использовании разбавителей TotalEnergies оказался в 1,5 и более раз выше, чем для керосина. ИК-спектры смесей экстрагента и разбавителей свидетельствуют о способствовании всех трёх разбавителей процессу димеризации экстрагента, а также объясняют различия в их экстракционной способности. Rare earth elements are critically important metals for high-tech technologies. Phosphoric acid, which is the resulting solution of apatite decomposition process in the fertilizers production, contains up to 0.1 % of rare earth elements and can be a raw material for their obtaining as by-products. Thus, the paper considers the solvent extraction of erbium and ytterbium from phosphoric acid solutions with di-2-ethylhexylphosphoric acid as an extractant. Besides the extractant, the extraction process depends also on a diluent, the composition and physical-chemical properties of which directly affect the extraction degree, distribution and separation coefficients, the stability of the resulting emulsion and the separation time of aqueous and organic phases. The article compares three types of diluents: traditionally used kerosene and aliphatic diluents Elixore 205 and Isane Biolife 58 produced by TotalEnergies. A significant improvement in extraction parameters was revealed when using a mixture of extractant with diluents by TotalEnergies compared to kerosene. The best extraction of erbium is observed when using the Isane Biolife 58: ratio Vextargent:Vdiluent= 1:10 provides extraction 1.5–2 times higher, and the extraction degree of 80% is achieved at a ratio of 1:4. The separation coefficient for erbium and ytterbium turned out to be 1.5 or more times higher than for kerosene. The IR spectra of the extragent and diluents mixtures indicate that all three diluents contribute to the extragent dimerization process and explain the differences in its extraction ability.
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43

Kunimura, Shinsuke y Jun Kawai. "Handy waveguide TXRF spectrometer for nanogram sensitivity". Powder Diffraction 23, n.º 2 (junio de 2008): 146–49. http://dx.doi.org/10.1154/1.2919826.

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A specimen containing nanograms of sulfur, calcium, and 3d transition metal elements was measured by incident X-ray beams of various sizes restricted by a waveguide placed in a portable TXRF spectrometer. The signal to background ratios of spectra decreased with an increase in incident X-ray beam size. The portable spectrometer was also applied to rainwater and a specimen containing antimony and rare earth elements. Nanograms of elements in these specimens were detected by K-line or L-line excitation.
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44

Gao, Zhou, Xing Jiang, Xingbo Wang, Yongji Chen, Jian Liu, Haibiao Chen, Yuan Lin y Feng Pan. "Rare-earth element doping in glass frit for improved performance in silicon solar cells". Functional Materials Letters 12, n.º 06 (diciembre de 2019): 1950080. http://dx.doi.org/10.1142/s1793604719500802.

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Glass frit plays an important role in the silver paste for silicon solar cells. In this work, we prepare glass frit doped with different rare-earth elements (Y, La, Sm, Er) and study how the doping element affects the performance of the solar cells. Solar cells with La-doped and Sm-doped glass frits show average conversion efficiencies higher than 17.5%, while solar cells with Y-doped or Er-doped frit show lower efficiencies. By analyzing the Raman spectra of the rare-earth doped glass frits, we find that the average coordination number of Te–O ([Formula: see text]) in the glass can be tuned by the rare-earth dopant. La or Sm doping leads to a moderate value of [Formula: see text], which is believed to achieve a glass formation ability that optimizes the structure of the Ag–Si interface of the cell for the best performance.
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45

Silva, Z. R., D. M. A. Melo, A. C. Lima, E. Longo, M. A. F. Melo y A. E. Martinelli. "Room temperature photoluminescence of (RE)NiO3 (RE=La, Y, Er, Ho, Nd and La1-xYx)". Cerâmica 53, n.º 326 (junio de 2007): 165–68. http://dx.doi.org/10.1590/s0366-69132007000200009.

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The nature of visible photoluminescence (PL) at room temperature in amorphous (RE)NiO3 (RE=La, Y, Er, Ho, Nd and La1-xYx) is discussed. Powders of this system were prepared by the polymeric precursor technique. The presence of broad PL band emission spectra at room temperature indicated increasing structural order with addition of rare earth elements.
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46

Rebohle, L. y Wolfgang Skorupa. "MOS Light Emitting Devices Based on Rare-Earth Ion Implantation". Materials Science Forum 590 (agosto de 2008): 117–38. http://dx.doi.org/10.4028/www.scientific.net/msf.590.117.

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In this article we will give an overview of our work devoted to Si-based light emission which was done in the last years. Si-based light emitters were fabricated by ion implantation of rare earth elements into the oxide layer of a conventional MOS structure. Efficient electroluminescence was obtained for the wavelength range from UV to the visible by using a transparent top electrode made of indium-tin oxide. In the case of Tb-implantation the best devices reach an external quantum efficiency of 16 % which corresponds to a power efficiency in the order of 0.3 %. The properties of the microstructure, the IV characteristics and the electroluminescence spectra were evaluated. The electroluminescence was found to be caused by hot electron impact excitation of rare earth ions, and the electric phenomena of charge transport, luminescence centre excitation, quenching and degradation are explained in detail.
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47

Al-Jubbori, M. A., H. H. Kassim, E. M. Raheem, I. M. Ahmed, Z. T. Khodair, F. I. Sharrad y I. Hossain. "Nuclear Structure of Rare-Earth 172Er, 174Yb, 176Hf, 178W, 180Os Nuclei". Ukrainian Journal of Physics 67, n.º 2 (1 de abril de 2022): 127. http://dx.doi.org/10.15407/ujpe67.2.127.

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Using the method with new empiric equation (NEE) and the model of interacting bosons (IBM-1), we study the ground-state band and the gamma- and beta-emission spectra of erbium (Er) and osmium (Os) elements with N = 104. The absolute B(E2) strengths for the nuclei are determined. The properties of the potential energy surface are investigated within IBM-1. The ratio Ey(I + 2)/(I) as a function of the angular momentum (I) and the characteristics of the yrast states are found. The constructed plots indicate that all nuclei of 172Er, 174Yb, 176Hf, 178W, and 180Os have a rotational SU(3) character. The staggering factors of available measured data are considered. The results of both models agree well with available experimental data for 172Er, 174Yb, 176Hf, 178W, and 180Os nuclei.
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48

Ogasawara, H., A. Kotani y B. T. Thole. "Lifetime effect on the multiplet structure of 4dx-ray-photoemission spectra in heavy rare-earth elements". Physical Review B 50, n.º 17 (1 de noviembre de 1994): 12332–41. http://dx.doi.org/10.1103/physrevb.50.12332.

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49

Wendt, Michael y Jan Dellith. "M Spectra of the Rare Earth Elements Measured with an Ultra-Thin Window Si(Li) Detector". Microchimica Acta 145, n.º 1-4 (1 de abril de 2004): 261–65. http://dx.doi.org/10.1007/s00604-003-0164-4.

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Yamada, Tetsuo, Takeshi Yamao y Shinichi Sakata. "Development of SiAlON - From Mechanical to Optical Applications". Key Engineering Materials 352 (agosto de 2007): 173–78. http://dx.doi.org/10.4028/www.scientific.net/kem.352.173.

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Various rare-earth-doped α-SiAlON powders with high purity were prepared to study mechanical and optical properties of SiAlON-based functional materials in connection with ionic radius and electronic structure of rare-earth elements. Single phase rare-earth-doped α-SiAlON powders were obtained at a temperature as low as 1873 K by heating powder mixtures of rare-earth oxide, AlN and highly active ultrafine amorphous Si3N4. Bending strength of highly dense rare-earth-doped α/β-SiAlON-based ceramics was increased with decreasing radii of rare-earth ions, i.e., Yb-SiAlON-based ceramics exhibited excellent high-temperature strength and oxidation resistance caused by the small ionic radius of ytterbium. As for optical application, α-SiAlON is an excellent host lattice with good thermal and chemical stability for doping rare-earth element which activates photoluminescence. Europium-doped Ca-α-SiAlON phosphor formulated as CaxEuy(Si,Al)12(O,N)16 (where 0<x+y<2) was prepared to obtain high quality phosphor with high brightness and desired emission characteristics. Photoluminescence spectra of the resultant Europium-doped Ca-α-SiAlON exhibited high emission intensity at peak wavelength of 580-600 nm giving the better yellow color tone than Cerium-doped yttrium aluminum garnet for applying white LED. It was demonstrated that nitrides or oxynitrides were the innovative materials for the diverse range of high performance specialty applications.
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