A comparative study on the luminescence properties of Ce3+/Tb3+ doped Gd-based host nanomaterials

Science.gov (United States)

Jadhao, Charushila Vasant; Rani, Barkha; Sahu, Niroj Kumar

2018-04-01

A comparative study on the crystal phases and their respective luminescence behaviour of Gd3+ based host materials such as GdPO4, GdF3, GdVO4 and Gd2O3 sensitized with 7at.% Ce3+ and activated with 5 at.% Tb3+ have been reported. The nanomaterials were prepared by polyol method using ethylene glycol as solvent and found to have different crystal structures such as monoclinic, orthorhombic, tetragonal and cubic phase. Clear characteristics emission from Tb3+ has been observed in all the samples when excited in the absorption wavelength of Ce3+ and Gd3+ (˜280 nm). Among all the above materials, intense emission of Tb3+ is found in GdPO4 followed by GdF3, Gd2O3 and GdVO4 respectively. The Tb3+ emission is strongly influenced by the energy transfer process and crystal structure of the host materials and hence this study will be important for choosing suitable materials for display devices and biomedical applications.

Perpendicular exchange coupling effects in ferrimagnetic TbFeCo/GdFeCo hard/soft structures

Science.gov (United States)

Wang, Ke; Wang, Yahong; Ling, Fujin; Xu, Zhan

2018-04-01

Bilayers consisting of magnetically hard TbFeCo and soft GdFeCo alloy were fabricated. Exchange-spring and sharp switching in a step-by-step fashion were observed in the TbFeCo/GdFeCo hard/soft bilayers with increasing GdFeCo thickness. A perpendicular exchange bias field of several hundred Oersteds is observed from the shift of minor loops pinned by TbFeCo layer. The perpendicular exchange energy is derived to be in the range of 0.18-0.30 erg/cm2. The exchange energy is shown to increase with the thickness of GdFeCo layer in the bilayers, which can be attributed to the enhanced perpendicular anisotropy of GdFeCo layer in our experimental range.

Lanthanide phosphonates: Synthesis, thermal stability and magnetic characterization

Energy Technology Data Exchange (ETDEWEB)

Amghouz, Z., E-mail: amghouz.uo@uniovi.es [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Garcia, J.R.; Garcia-Granda, S. [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Clearfield, A. [Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States); Rodriguez Fernandez, J.; Pedro, I. de [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Report of the complete series of lanthanide 1,4-phenylbis(phosphonate). Black-Right-Pointing-Pointer Synthesis under conventional hydrothermal synthesis or microwave-assisted hydrothermal synthesis. Black-Right-Pointing-Pointer Cation size is the key factor for the structural and particles size variations. Black-Right-Pointing-Pointer Thermal behaviour is characterized by unusual very high thermal stability. - Abstract: Series of novel organic-inorganic hybrids materials based on trivalent lanthanides (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and 1,4-phenylbis(phosphonate) obtained under hydrothermal conditions either by oven heat or microwave irradiation. The anhydrous compounds containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, are isostructural. However, the compounds based on Y, Er, Tm, Yb, and Lu are hydrated and their structures have not yet been solved. The series of compounds are characterized by PXRD, TEM, SEM-EDX and thermal analyses (TG-MS and DSC). TEM study show a variable particles size with a minimum mean-particle size of ca. 30 nm. These compounds exhibit unusual very high thermal stability. The size of particles and the thermal stability are depending on lanthanide(III) cation features. All the investigated materials show paramagnetic behaviour. The magnetic susceptibility data follow a Curie-Weiss laws with paramagnetic effective moments in good agreement with those expected for Ln{sup 3+} free ions.

The equilibrium diagram and some properties of alloys Gd5Sb3-Tb5Sb3 system

International Nuclear Information System (INIS)

Azizov, Yu.S.; Abulkhaev, V.D.; Ganiev, I.N.

2001-01-01

The purpose of present work is investigation equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system in total range of concentrations. Equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system investigated by methods of difference-thermal, roentgen-phase and metallographic analyses. For the first time on the base of difference-thermal, roentgen-phase and metallographic analyses was formed the equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system. Was determined the cristal-chemical parameters of solid solutions with general formula Gd x Tb 5 - x Sb 3

Theoretical and experimental spectroscopic studies of the first highly luminescent binuclear hydrocinnamate of Eu(III), Tb(III) and Gd(III) with bidentate 2,2'-bipyridine ligand

Energy Technology Data Exchange (ETDEWEB)

Marques, Lippy F.; Correa, Charlane C.; Garcia, Humberto C. [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG 36036-330 (Brazil); Martins Francisco, Thiago [Departamento de Física-ICEx, Universidade Federal de Minas Gerais, Pampulha, Belo Horizonte-MG 30123-970 (Brazil); Ribeiro, Sidney J.L. [Instituto de Química, Universidade Estadual Paulista Júlio de Mesquita Filho-UNESP, CP 355, Araraquara-SP 14801-970 (Brazil); Dutra, José Diogo L.; Freire, Ricardo O. [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Machado, Flávia C., E-mail: flavia.machado@ufjf.edu.br [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG 36036-330 (Brazil)

2014-04-15

In this paper, the synthesis of three new binuclear lanthanide (III) complexes [Ln{sub 2}(cin){sub 6}(bpy){sub 2}] (Ln=Eu (1), Tb (2), Gd (3), cin=hydrocinnamate anion; bpy=2,2'-bipyridine), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermal analysis (TGA/DTA) are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structures of 1–3 reveal that all compounds are isostructural and that each lanthanide ion is nine-coordinated by oxygen and nitrogen atoms in an overall distorted tricapped trigonal-prismatic geometry. Eu(III) complex structure was also calculated using the Sparkle model for lanthanide complexes and the intensity parameters (Ω{sub 2}, Ω{sub 4}, and Ω{sub 6}), calculated from the experimental data and from Sparkle/PM3 model. The theoretical emission quantum efficiencies obtained for Sparkle/PM3 structures are in excellent agreement with the experimental values, clearly attesting to the efficacy of the theoretical models. The theoretical procedure applied here shows that the europium binuclear compound displays a quantum yield about 65% suggesting that the system can be excellent for the development of efficient luminescent devices. Highlights: • First binuclear Ln{sup 3+}-hydrocinnamate have been synthesized and characterized. • Eu{sup 3+}, Tb{sup 3+} and Gd{sup 3+} complexes photoluminescence properties were investigated. • Theoretical approaches for Eu{sup 3+} complex luminescence has been performed. • An energy level diagram is used to establish the ligand-to-metal energy transfer. • 65% Quantum yield suggests an excellent system for luminescent devices.

New lanthanide hydrogen phosphites LnH (P03H)2 2H20

International Nuclear Information System (INIS)

Durand, J.; Tijani, N.; Cot, L.; Loukili, M.; Rafiq, M.

1988-01-01

LnH ((P0 3 H) 2 2H 2 0 is prepared from lanthanide oxide and phosphorous acid with Ln = La, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er or Tm. By thermal gravimetric analysis LnH (P0 3 H) 2 and LnH 2 P 2 0 5 (P0 3 H) 2 are obtained. The three salts are orthorhombic. Parameters and space groups are given for the three salts of each lanthanide. 4 tabs., 13 refs

Lanthanide contraction effect on crystal structures of lanthanide coordination polymers with cyclohexanocucurbit[6]uril ligand

Energy Technology Data Exchange (ETDEWEB)

Zheng, Li-Mei [College of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001 (China); Liu, Jing-Xin, E-mail: jxliu411@ahut.edu.cn [College of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002 (China)

2017-01-15

A series of compounds based on the macrocyclic ligand cyclohexanocucurbit[6]uril (Cy6Q[6]) with formulas (Ln(H{sub 2}O){sub 6}Cy6Q[6])·2(CdCl{sub 4})·H{sub 3}O·xH{sub 2}O [isomorphous with Ln=La (1), Ce (2), Pr (3) and Nd (4), x=11 (1), 11 (2), 10 (3) and 11 (4)], (Sm(H{sub 2}O){sub 5}Cy6Q[6])·2(CdCl{sub 4})·H{sub 3}O·10H{sub 2}O (5) and (Ln(H{sub 2}O){sub 5}(NO{sub 3})@Cy6Q[6])·2(CdCl{sub 4})·2H{sub 3}O·xH{sub 2}O [isomorphous with Ln=Gd (6), Tb (7) and Dy (8), x=8 (6), 6 (7) and 6 (8)], have been successfully synthesized by the self-assembly of Cy6Q[6] with the corresponding lanthanide nitrate under hydrochloric acid aqueous solution in the presence of CdCl{sub 2}. Single-crystal X-ray diffraction analyses revealed that compounds 1–8 all crystallize in monoclinic space group P2{sub 1}/c, and display 1D coordination polymer structures. The lanthanide contraction effect on the structures of 1–8 has also been investigated and discussed in detail. In contrast, the reaction of Cy6Q[6] with the Ho(NO){sub 3}, Tm(NO){sub 3}, Yb(NO){sub 3} under the same conditions resulted in the compounds 9–11 with formulas Cy6Q[6]·2(CdCl{sub 4})·2H{sub 3}O·xH{sub 2}O [isomorphous with x=10 (9), 10 (10), and 9 (11)], in which no lanthanide cations are observed. The structural difference of these compounds indicates that the Cy6Q[6] may be used in the separation of lanthanide cations. - Graphical abstract: The reaction of cyclohexanocucurbit[6]uril with lanthanide ions (La{sup 3+}, Ce{sup 3+}, Pr{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}, Ho{sup 3+}, Tm{sup 3+} and Yb{sup 3+}) under hydrochloric acid in the presence of CdCl{sub 2} resulted in eleven compounds, which demonstrate interesting lanthanide contraction effect and provide a means of separating lanthanide ions. - Highlights: • Eleven compounds of the Ln{sup 3+} with the Cy6Q[6] were synthesized and described. • Compounds 1-8 demonstrate interesting lanthanide contraction effect. �

Neutron diffraction studies on GdB{sub 6} and TbB{sub 6} powders

Energy Technology Data Exchange (ETDEWEB)

Luca, S.E.; Amara, M.; Galera, R.M.; Givord, F.; Granovsky, S.; Isnard, O.; Beneu, B

2004-07-15

We report here the first powder neutron diffraction study of GdB{sub 6} and TbB{sub 6}. GdB{sub 6} and TbB{sub 6} order antiferromagnetically at 15 and 21 K, respectively. In both compounds the transition at T{sub N} is of the first order. Moreover GdB{sub 6} presents a second spontaneous magnetic transition at T{sup *}=8 K. The present study shows that, in both compounds, the magnetic propagation vectors belong to the <((1)/(4)) ((1)/(4)) ((1)/(2))> star and that the direction of the magnetic moment is perpendicular to the ((1)/(2)) component of the wave-vector in GdB{sub 6}, while in TbB{sub 6} the moment is parallel to it. The deduced low-temperature values of the magnetic moments agree with those of the respective rare-earth trivalent ions.

Synthesis and luminescent spectroscopy of lanthanide complexes with dimethylpyridine-2,6-dicarboxylate (dmpc)

Energy Technology Data Exchange (ETDEWEB)

Taha, Ziyad A., E-mail: tahaz33@just.edu.jo [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Ajlouni, Abdulaziz M.; Hijazi, Ahmed K. [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Al-Rawashdeh, Nathir A. [Department of Applied Chemical Sciences, Faculty of Arts and Sciences, Jordan University of Science and Technology, Irbid 22110 (Jordan); Department of Chemistry, United Arab Emirates University, Al Ain 15551 (United Arab Emirates); Al-Hassan, Khader A.; Al-Haj, Yaser A. [Department of Chemistry, Faculty of Science, Yarmouk University, 1163 Irbid (Jordan); Ebqa' ai, Mohammad A. [Al-Qunfudah Center For Scientific Research, Umm Al-Qura University, College in Al-Qunfudah, Makkah (Saudi Arabia); Altalafha, Ammar Y. [Department of Chemistry, Faculty of Science, Yarmouk University, 1163 Irbid (Jordan)

2015-05-15

A series of lanthanide complexes with the general formulae [Ln(dmpc)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}]NO{sub 3} (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er) and [La(dmpc)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}]NO{sub 3} were prepared by direct reaction between hydrated lanthanide(III) nitrate and dimethylpyridine-2,6-dicarboxylate (dmpc) in a 1:1 M ratio in ethylacetate–chloroform mixture. The luminescence properties of the dmpc and its Ln(III) complexes were investigated in solid state and in methanol, DMF and DMSO solutions. The Tb–dmpc, Eu–dmpc, Sm–dmpc and Dy–dmpc complexes exhibit characteristic luminescence of Tb(III), Eu(III), Sm(III) and Dy(III) ions indicating energy transfer from the dmpc to the Ln(III) ions. Scavenging activities of the dmpc and its Ln(III) complexes on DPPH{sup •} free radical were investigated in DMSO solution at a different concentrations ranges. - Highlights: • Nine new lanthanide complexes with dmpc ligand are prepared and characterized. • Ln–dmpc {Ln=Eu, Tb, Sm, Dy} complexes exhibit characteristic emissions of Ln ions. • The solvent effect on the luminescence intensity is investigated. • The antioxidant activity of the dmpc is enhanced upon complexation with lanthanide.

The development of new phosphors of Tb3+/Eu3+ co-doped Gd3Al5O12 with tunable emission

Science.gov (United States)

Teng, Xin; Wang, Wenzhi; Cao, Zhentao; Li, Jinkai; Duan, Guangbin; Liu, Zongming

2017-07-01

The gadolinium aluminum garnets Gd3Al5O12 (GdAG) activated with Tb3+/Eu3+ were successfully prepared via co-precipitation method at 1500 °C in this work. The crystal structure stabilization, elements analysis, microphotograph, PL/PLE spectra, decay behavior and quantum efficiency were discussed in detail. The metastable GdAG compounds been effectively stabilized by doping with smaller 10 at.% Tb3+, which then allows the development of new phosphors of (Gd0.9-xTb0.1Eux)3Al5O12 (GdAG:Tb3+/Eu3+, x = 0-0.03) for opto-functionality explorations. The PLE/PL spectra displays that the strongest PLE peak was located at ∼276 nm, which overlaps the 8S7/2 → 6IJ transition of Gd3+. Under 276 nm excitation, the phosphors exhibited both Tb3+ and Eu3+ emissions at 548 nm (green, 5D4 → 7F5 transition of Tb3+) and 592 nm (orange-red, 5D0 → 7F1 transition of Eu3+), respectively. The emission intensities of Tb3+ and Eu3+ remarkably varied with the Eu3+ incorporation. As a consequence, the emission color can be readily tuned from approximately green to orange-red. Fluorescence decay analysis found that the lifetime for the Tb3+ emission rapidly decreased conforming to the Tb3+ → Eu3+ energy transfer, and the energy transfer efficiency was calculated. Owing to the Gd3+ → Eu3+ and Gd3+ → Tb3+ energy transfer, the emission intensities of Tb3+ and Eu3+ in (Gd0.9-xTb0.1Eux)AG phosphor were higher than (Y0.87Tb0.1Eu0.03)AG and (Lu0.87Tb0.1Eu0.03)AG system. The (Gd0.9-xTb0.1Eux)AG garnet phosphors developed in this work may serve as a new type of phosphor which hopefully meets the requirements of various lighting and optical display applications.

Sol-gel syntheses, luminescence, and energy transfer properties of α-GdB5O9:Ce(3+)/Tb(3+) phosphors.

Science.gov (United States)

Sun, Xiaorui; Gao, Wenliang; Yang, Tao; Cong, Rihong

2015-02-07

Sol-gel method was applied to prepare homogenous and highly crystalline phosphors with the formulas α-GdB5O9:xTb(3+) (0 ≤ x ≤ 1), α-Gd1-xCexB5O9 (0 ≤ x ≤ 0.40), α-GdB5O9:xCe(3+), 0.30Tb(3+) (0 ≤ x ≤ 0.15) and α-GdB5O9:0.20Ce(3+), xTb(3+) (0 ≤ x ≤ 0.10). The success of the syntheses was proved by the linear shrinkage or expansion of the cell volumes against the substitution contents. In α-GdB5O9:xTb(3+), an efficient energy transfer from Gd(3+) to Tb(3+) was observed and there was no luminescence quenching. The exceptionally high efficiency of the f-f excitations of Tb(3+) implies that these phosphors may be good green-emitting UV-LED phosphors. For α-Gd1-xCexB5O9, Ce(3+) absorbs the majority of the energy and transfers it to Gd(3+). Therefore, the co-doping of Ce(3+) and Tb(3+) leads to a significant enhancement in the green emission of Tb(3+). Our current results together with the study on α-GdB5O9:xEu(3+) in the literature indicate that α-GdB5O9 is a good phosphor host with advantages including controllable preparation, diverse cationic doping, the absence of concentration quenching, and effective energy transfer.

Luminescence, Energy Transfer and Tunable Color of Ce3+- and Tb3+-Activated Na3Gd(BO3)2 Phosphors

Science.gov (United States)

Zhang, Xinguo; Pan, Jialiang; Mo, Fuwang

2017-07-01

A series of blue Na3Gd(BO3)2:Ce3+ and blue-to-green color-tunable Na3Gd (BO3)2:Ce3+,Tb3+ phosphors were synthesized by the solid-state method. The luminescence, concentration quenching and energy transfer (ET) process of Na3Gd(BO3)2:Ce3+,Tb3+ were investigated. Both Ce3+ and Tb3+ occupy the Gd3+ site in the Na3Gd(BO3)2 host. Na3Gd(BO3)2:Ce3+ exhibits strong ultraviolet absorption and broadband blue emission. The Ce3+ sensitization effect on Tb3+ has been verified by the variation of PL/PLE spectra, the Ce3+ decay lifetimes and the energy transfer efficiency of Na3Gd(BO3)2:Ce3+,Tb3+ phosphors. The maximum Ce3+-Tb3+ ET efficiency has been calculated to be 95%. The emitting color of the obtained phosphors can be modulated from blue (0.179, 0.204) through bluish-green (0.271, 0.391) to green (0.349, 0.551) by properly changing the ratio of Ce3+/Tb3+.

Ultrafast magnetization dynamics of lanthanide metals and alloys

Energy Technology Data Exchange (ETDEWEB)

Sultan, Muhammad

2012-05-14

In this study, the laser-induced magnetization dynamics of the lanthanide ferromagnets Gadolinium (Gd), Terbium (Tb) and their alloys is investigated using femtosecond (fs) time-resolved x-ray magnetic circular dichroism (XMCD), the magneto-optical Kerr effect (MOKE) and magnetic second harmonic generation (MSHG). The magnetization dynamics is analyzed from the time scale of a few fs up to several hundred picoseconds (ps). The contributions of electrons, phonons, spin fluctuations, as well as the temporal regimes corresponding to the spin-orbit and exchange interactions are disentangled. In addition to possible applications in magnetic storage devices, understanding magnetization dynamics in lanthanides is also important because of their different magnetic structure compared to well-studied itinerant ferromagnets. Lanthanides are model Heisenberg-ferromagnets with localized 4f magnetic moments and long range magnetic ordering through indirect exchange interaction. By optical excitation of the conduction electrons, which mediate the exchange interaction, and studying the induced dynamics of the localized 4f and delocalized 5d6s magnetic moments, one can obtain insight into the angular momentum transfer at ultrafast time scales. Moreover, lanthanides offer the possibility to tune spin-lattice coupling via the 4f shell occupation and the concomitant changes in the 4f spin and orbital moments due to Hund's rules. Utilizing this fact, the importance of spin-lattice coupling in laser-induced demagnetization is also analyzed by comparing the magnetization dynamics in Gd and Tb. By investigating the magnetization dynamics of localized 4f moments of Gd and Tb using time-resolved XMCD, it is found that the demagnetization proceeds in both metals in two time scales, following fs laser excitation, which are classified as: (i) non-equilibrium (t > 1 ps), with respect to equilibration of electron and phonon temperatures. The

Preparation and characterization of the adducts between lanthanide methanesulfonates and thioxane oxide

International Nuclear Information System (INIS)

Castro e Silva, E. de.

1983-01-01

The preparation and characterization of the adduct between lanthanide methanesulphonates and thioxane oxide are presented. The compounds characterization by conductance measurements, X-ray powder patterns, infrared, visible and fluorescence spectra, TG, DTG and DTA curves was made. According to the X-ray patterns, three isomorphous series were obtained: a-La-Gd b-Tb-Dy and c-Ho-Lu, Y. (M.J.C.) [pt

Optimization of the radio lanthanides separation device

International Nuclear Information System (INIS)

Vera T, A. L.

2009-01-01

At present, cancer is a major cause of mortality in our country, therefore, its prevention, diagnosis and treatment are vital to health systems. The cancer treatment and other diseases, from monoclonal antibodies, peptides, or amino macro aggregates marked with beta particle emitting radionuclides, is a highly promising field. The radioactive lanthanides: Pm, Tb, Ho, and Lu are beta emitters, which possess nuclear and chemical properties, which have shown their feasibility as radioisotopes of radiotherapeutic use. However, these radioisotopes are not available commercially in this connection, the Research Laboratory of Radioactive Materials of the National Institute of Nuclear Research, has developed the methodology of production of these radioisotopes and based on this work is designed, constructed and installed the radio lanthanides separation device for the radioisotopes production routinely. This device is part of the cell, , which has and auxiliary air service, an extraction system and is protected with a 10 cm of lead shielding. The radio lanthanides separation device is manual and easy to handle. The main function of this equipment is the radio lanthanides separation from extractive chromatography through packed columns with a commercial resin (Ln SPS) and coated on the top and bottom by fiberglass. The radio lanthanides separation device comprises a main carrousel where the separation columns and elution containers are mounted. It also has a system of open irradiation vials, carrier samples for columns and glassware. This paper presents a detailed description of the radio lanthanides separation device and its management, which allows the radioisotopes production Pm, Tb, Ho, and Lu from the separation of its parents Nd, Dy, Gd, and Yb respectively. (Author)

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy(3+),Tb(3+),Eu(3+) phosphors.

Science.gov (United States)

Guan, Hongxia; Sheng, Ye; Xu, Chengyi; Dai, Yunzhi; Xie, Xiaoming; Zou, Haifeng

2016-07-20

A series of Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped GdF3 phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF3. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF3:Dy(3+), GdF3:Tb(3+) and GdF3:Eu(3+) samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF3 host, the different color hues of green and red light are obtained by co-doped Dy(3+), Tb(3+) and Tb(3+), Eu(3+) ions in the GdF3 host, respectively. Besides, there exist two energy transfer pairs in the GdF3 host: (1) Dy(3+) → Tb(3+) and (2) Tb(3+) → Eu(3+). More significantly, in the Dy(3+), Tb(3+), and Eu(3+) tri-doped GdF3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu(3+). In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy(3+), Tb(3+), Eu(3+) tri-doped GdF3 materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.

The N=82 gap in /sup 146/Gd from beta -decay studies of Tb isotopes

CERN Document Server

Styczen, J; Kleinheinz, P; Piiparinen, M

1981-01-01

The beta -decay study of 23 s /sup 146/Tb suggests a ( pi h/sub 11/2/ nu d/sup -1//sub 3/2/) 5/sup -/ configuration for this activity. In its decay the authors have identified a pi h/sub 11/2/ to nu h/sub 9/2 / GT decay branch which populates neutron particle-hole states in /sup 146/Gd. Hence the N=82 single particle energy gap is less than 4 MeV. Neutron one-particle two-hole and two-particle one-hole states in /sup 145/Gd and /sup 147/Gd were identified in the beta -decays of 29 s /sup 145/Tb and 1.6 h /sup 147/Tb. (11 refs).

Experimental and theoretical study of pure and doped crystals: Gd2O2S, Gd2O2S:Eu3+ and Gd2O2S:Tb3+

Science.gov (United States)

Wang, Fei; Chen, Xiumin; Liu, Dachun; Yang, Bin; Dai, Yongnian

2012-08-01

Quantum chemistry and experimental method were used to study on pure and doped Gd2O2S crystals in this paper. The band structure and DOS diagrams of pure and doped Gd2O2S crystals which calculated by using DFT (Density Functional Theory) method were illustrated to explain the luminescent properties of impurities in crystals. The calculations of the crystal structure were finished by using the program of CASTEP (Cambridge Sequential Total Energy Package). The samples showed the characteristic emissions of Tb3+ ions with 5D4-7FJ transitions and Eu3+ ions with 5D0-7FJ transitions which emit pure green luminescence and red luminescence respectively. The experimental excitation spectra of Tb3+ and Eu3+ doped Gd2O2S are in agreement of the DOS diagrams over the explored energy range, which has allowed a better understanding of different luminescence mechanisms of Tb3+ and Eu3+ in Gd2O2S crystals.

Electronic structure of lanthanide scandates

Science.gov (United States)

Mizzi, Christopher A.; Koirala, Pratik; Marks, Laurence D.

2018-02-01

X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and density functional theory calculations were used to study the electronic structure of three lanthanide scandates: GdSc O3,TbSc O3 , and DySc O3 . X-ray photoelectron spectra simulated from first-principles calculations using a combination of on-site hybrid and GGA +U methods were found to be in good agreement with experimental x-ray photoelectron spectra. The hybrid method was used to model the ground state electronic structure and the GGA +U method accounted for the shift of valence state energies due to photoelectron emission via a Slater-Janak transition state approach. From these results, the lanthanide scandate valence bands were determined to be composed of Ln 4 f ,O 2 p , and Sc 3 d states, in agreement with previous work. However, contrary to previous work the minority Ln 4 f states were found to be located closer to, and in some cases at, the valence band maximum. This suggests that minority Ln 4 f electrons may play a larger role in lanthanide scandate properties than previously thought.

Electrical characteristics of hybrid detector based Gd2O2S:Tb-Selenium for digital radiation imaging

International Nuclear Information System (INIS)

Kang, Sang-Sik; Park, Ji-Koon; Choi, Jang-Yong; Cha, Byung-Yul; Cho, Sung-Ho; Nam, Sang-Hee

2005-01-01

Fine Gd 2 O 2 S:Tb powders were synthesized by using a solution-combustion method for a high-resolution digital X-ray imaging detector. The PL spectrum showed that the phosphor was fully crystallized and that the Tb 3+ ions substituted well for the Gd 3+ sites. To investigate the X-ray response of the phosphor, a uniform Gd 2 O 2 S:Tb film was grown using a screen-printing method. The X-ray sensitivities of the 100 μm-Gd 2 O 2 S:Tb/30 μm -Se and 200 μm -Se detector were 470 and 420 pC/cm 2 /mR, respectively, at an electric field of 10 V/μm. The results of the study suggest that the hybrid detector has a significant potential in the application of digital radiography and fluoroscopy systems

Critical evaluation and thermodynamic optimisation of the Si-RE systems: Part II. Si-RE system (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y)

International Nuclear Information System (INIS)

Kim, Junghwan; Jung, In-Ho

2015-01-01

Highlights: • The (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems have been reviewed. • The thermodynamic optimization of the (Si-RE) systems have been performed. • Systematic changes and similarities in the (Si-RE) systems were found. • The systematic approach resolved inconsistencies in the experimental data. • The systematic approach was used to assess the unexplored phase diagrams. - Abstract: A critical evaluation and optimisation of all available phase diagrams and thermodynamic data of the (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems was conducted to obtain reliable thermodynamic functions of all the phases in the system. In the thermodynamic modelling, a systematic analysis involving the similarity and periodicity observed in the lanthanide series was applied to resolve inconsistencies in the experimental data and to estimate the unknown thermodynamic properties and phase equilibria data. In particular, the phase diagrams and thermodynamic properties of (Si-Tm) and (Si-Lu) systems which are rarely investigated can be predicted from this approach. Systematic trends in thermodynamic properties of solid and liquid phases and phase diagram of the entire (Si-RE) systems were summarized

Complexes of Y, La, and lanthanides with m-aminobenzoic acid

International Nuclear Information System (INIS)

Rzaczynska, Z.; Brzyska, W.

1989-01-01

m-Aminobenzoates of Y, La and lanthanides prepared in the reaction of the hydroxides of metal with m-aminobenzoic acid in solution have the general formula Ln(m-C 6 H 4 NH 2 COO) 3 .nH 2 O where n = 4 for Ho, Tm, n = 5 for Y, Sm, Dy, Er, Lu, and n = 6 for La, Nd, Eu, Gd, Tb, Yb. The water molecules in the hydrated compounds are in the outer coordination sphere. On heating in air at 350-410K dehydration occurs and anhydrous m-aminobenzoates Ln(m-C 6 H 4 NH 2 COO) 3 are formed. On the basis of the IR spectra it was found that the metal in hydrated m-aminobenzoate of lanthanides is simultaneously coordinated through amino- and carboxyl groups whereas in anhydrous m-aminobenzoates of lanthanides only trough the bidentate carboxyl group. From X-ray analysis it was stated that the hydrated m-aminobenzoates of lanthanides are isostructural in the whole range Y, La-Lu. (Author)

Photoluminescence and thermoluminescence properties of Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Gupta, Palvi; Bedyal, A.K. [School of Physics, Shri Mata Vaishno Devi University, Katra, 182320 Jammu and Kashmir (India); Kumar, Vinay, E-mail: vinaykdhiman@yahoo.com [School of Physics, Shri Mata Vaishno Devi University, Katra, 182320 Jammu and Kashmir (India); Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Khajuria, Y. [School of Physics, Shri Mata Vaishno Devi University, Katra, 182320 Jammu and Kashmir (India); Lochab, S.P. [Inter University Accelerator Centre, Anura Asaf Ali Marg, P. O. Box 10502, New Delhi 110067 (India); Pitale, S.S. [Crystal Technology Laboratory,TPD, Bhabha Atomic Research Centre Trombay, Mumbai 400085 (India); Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Ntwaeaborwa, O.M.; Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

2014-12-15

Energy level diagram of Tb{sup 3+} ion in the K{sub 3}Gd(PO{sub 4}){sub 2} host lattice. - Highlights: • First time, a detailed TL and PL study on undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Combustion method was employed to synthesize the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor. • Mechanism of excitation and emission in undoped and Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2} nanophosphor was given. - Abstract: Tb{sup 3+} doped nanoparticulate K{sub 3}Gd(PO{sub 4}){sub 2} phosphor was prepared by combustion method using urea as a fuel. The structure, optical and luminescent properties of the phosphor were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and thermoluminescence (TL) spectroscopy. In undoped K{sub 3}Gd(PO{sub 4}){sub 2}, the excitation and emission peaks at 273 nm and 323 nm belongs to the {sup 8}S{sub 7/2} → {sup 6}I{sub J(J=7/2)} and {sup 6}P{sub J(J=7/2)} → {sup 8} S{sub 7/2} transitions of Gd{sup 3+} while green emission was observed in the Tb{sup 3+} doped K{sub 3}Gd(PO{sub 4}){sub 2}. TL study was carried out after exposing the samples to γ-radiations (0.1–5 kGy) in the K{sub 3}Gd(PO{sub 4}){sub 2}:Tb{sup 3+} (1.5 mol%). The calculated kinetic parameters were compared with different methods. The band gap of the phosphor was estimated as 5.80 eV. The green shade of the Tb{sup 3+} ion with the CIE coordinates (x, y) as (0.29, 0.54) was in good agreement with the well known green phosphors.

Synthesis and photoluminescence properties of GdBO3:Ln3+ (Ln = Eu, Tb) nanofibers by electrospinning

International Nuclear Information System (INIS)

Shen, Hongzhi; Feng, Shuo; Wang, Ying; Gu, Yipeng; Zhou, Jing; Yang, Hang; Feng, Guanlin; Li, Liang; Wang, Wenquan; Liu, Xiaoyang; Xu, Dapeng

2013-01-01

Highlights: ► GdBO 3 :Ln 3+ nanofibers were synthesized successfully by electrospinning. ► The samples have the average diameter of 150 nm and the flexible morphology. ► The GdBO 3 : Eu 3+ nanofibers have the stronger orange emission. ► The luminescence properties are different from the reported bulk material. ► We describe the energy transform process of GdBO 3 :Ln 3+ system. - Abstract: GdBO 3 :Ln 3+ (Ln = Eu, Tb) nanofibers were synthesized using electrospinning combined with heat treatment. The synthesized nanofibers were characterized by X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, thermogravimetric and differential thermal analyses, and photoluminescence. The experimental results show that the flexible synthesized nanofibers have an average diameter of approximately 150 nm. The nanofibers consist of crystalline grains with diameters of about 40 nm and have a vaterite-type structure of GdBO 3 . The GdBO 3 :Eu 3+ nanofibers exhibit strong orange and weak red emissions with a low ratio of red to orange emission intensities, which is different from those of the reported bulk materials and nanoparticles. The luminescence properties of the synthesized GdBO 3 :Tb 3+ nanofibers are essentially consistent with those of the synthesized GdBO 3 :Tb 3+ powders by solid-state reaction.

Development of Tb{sup 3+} activated gadolinium aluminate garnet (Gd{sub 3}Al{sub 5}O{sub 12}) as highly efficient green-emitting phosphors

Energy Technology Data Exchange (ETDEWEB)

Teng, Xin; Li, Jinkai, E-mail: mse_lijk@ujn.edu.cn; Duan, Guangbin; Liu, Zongming, E-mail: ost_liuzm@ujn.edu.cn

2016-11-15

The powder processing of (Gd{sub 1-x}Tb{sub x}){sub 3}Al{sub 5}O{sub 12} (GdAG:Tb{sup 3+}) solid solutions was achieved through precursor synthesized via carbonate precipitation, followed by calcination at 1500 °C. The performance of the GdAG:Tb{sup 3+} phosphors were characterized by the combined techniques of XRD, FE-SEM, HR-TEM, PLE/PL, and fluorescence decay analyses. Lower Tb{sup 3+} doping can stabilize the crystal structure of GdAG garnet against its thermal decomposition. The GdAG:Tb{sup 3+} phosphors with good dispersion and fairly uniform particle morphology exhibit a series of {sup 5}D{sub 4}–{sup 7}F{sub J} transitions of Tb{sup 3+} with strongest green emission at ~544 nm ({sup 5}D{sub 4}–{sup 7}F{sub 5} transitions of Tb{sup 3+}) under UV excitation at ~277 nm (4f{sup 8}−4f{sup 7}5d{sup 1} transition of Tb{sup 3+}). The later is overlapping with {sup 8}S{sub 7/2}–{sup 6}I{sub J} intra f–f transition of Gd{sup 3+} indirectly suggesting the existence of energy transfer from Gd{sup 3+} to Tb{sup 3+}. With the Gd{sup 3+}–Tb{sup 3+} energy transfer, higher Tb{sup 3+} emission and quantum efficiency than the well-known YAG:Tb{sup 3+} and LuAG:Tb{sup 3+} were obtained in the present work. The effects of Tb{sup 3+} content on luminescent property of the phosphor, especially PLE/PL properties, fluorescence lifetime and quantum efficient, were thoroughly investigated, which were also compared to those of Tb{sup 3+}-activated YAG and LuAG compounds. The CIE chromaticity coordinates and quenching concentration of GdAG:Tb{sup 3+} were determined to be (~0.37, ~0.56) and ~10 at%, respectively. Keeping the optimum Tb{sup 3+} content at ~10 at%, the (Gd{sub 0.9}Tb{sub 0.1})AG phosphor possesses high internal and external quantum efficiencies of ~88.7% and ~73.6% under ~277 nm excitation, respectively. Owing to its improved luminescent property and high theoretical density, the phosphors of (Gd{sub 1-x}Tb{sub x})AG garnet developed in the present work are

Synthesis, crystal structure, optical and thermal properties of lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho).

Science.gov (United States)

Förg, Katharina; Höppe, Henning A

2015-11-28

Lanthanide hydrogen-polyphosphates Ln[H(PO3)4] (Ln = Tb, Dy, Ho) were synthesised as colourless (Ln = Tb, Dy) and light pink (Ln = Ho) crystalline powders by reaction of Tb4O7/Dy2O3/Ho2O3 with H3PO3 at 380 °C. All compounds crystallise isotypically (P2(1)/c (no. 14), Z = 4, a(Tb) = 1368.24(4) pm, b(Tb) = 710.42(2) pm, c(Tb) = 965.79(3) pm, β(Tb) = 101.200(1)°, 3112 data, 160 parameters, wR2 = 0.062, a(Ho) = 1363.34(5) pm, b(Ho) = 709.24(3) pm, c(Ho) = 959.07(4) pm, β(Ho) = 101.055(1)°, 1607 data, 158 parameters, wR2 = 0.058). The crystal structure comprises two different infinite helical chains of corner-sharing phosphate tetrahedra. In-between these chains the lanthanide ions are located, coordinated by seven oxygen atoms belonging to four different polyphosphate chains. Vibrational, UV/Vis and fluorescence spectra of Ln[H(PO3)4] (Ln = Tb, Dy, Ho) as well as Dy[H(PO3)4]:Ln (Ln = Ce, Eu) and the magnetic and thermal behaviour of Tb[H(PO3)4] are reported.

Luminescent properties of (Y,Gd)BO3:Bi3+,RE3+ (RE=Eu, Tb) phosphor under VUV/UV excitation

International Nuclear Information System (INIS)

Zeng Xiaoqing; Im, Seoung-Jae; Jang, Sang-Hun; Kim, Young-Mo; Park, Hyoung-Bin; Son, Seung-Hyun; Hatanaka, Hidekazu; Kim, Gi-Young; Kim, Seul-Gi

2006-01-01

Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors were prepared and their luminescent properties under vacuum ultraviolet (VUV)/UV excitation were investigated. Strong red emission for (Y,Gd)BO 3 :Bi 3+ ,Eu 3+ and strong green emission for (Y,Gd)BO 3 :Bi 3+ ,Tb 3+ are observed under VUV excitation from 147 to 200 nm with a much broader excitation region than that of single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 phosphor. Strong emissions are also observed under UV excitation around 265 nm where as nearly no luminescence is observed for single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 . The luminescence enhancement of Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors is due to energy transfer from Bi 3+ ion to Eu 3+ or Tb 3+ ion not only in the VUV region but also in the UV region. Besides, host sensitization competition between Bi 3+ and Eu 3+ or Tb 3+ is also observed. The investigated phosphors may be preferable for devices with a VUV light 147-200 nm as an excitation source such as PDP or mercury-free fluorescent lamp

Intercalation of lanthanide trichlorides in graphite

International Nuclear Information System (INIS)

Stumpp, E.; Nietfeld, G.

1979-01-01

The reactions of the whole series of lanthanide trichlorides with graphite have been investigated. Intercalation compounds have been prepared with the chlorides of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y whereas LaCl 3 , CeCl 3 , PrCl 3 and NdCl 3 do not intercalate. The compounds were characterized by chemical and X-ray analysis. The amount of c-axis increase is consistent with the assumption that the chlorides are intercalated in form of a chloride layer sandwich resmbling the sheets in YCl 3 . The chlorides which do not intercalate crystallize in the UCl 3 structure having 3 D arrangements of ions. Obviously, these chlorides cannot form sheets between the carbon layers. The ability of AlCl 3 to volatilize lanthanide chlorides through complex formation in the gas phase can be used to increase the intercalation rate strikingly. (author)

Giant exchange interaction in mixed lanthanides

Science.gov (United States)

Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

2016-01-01

Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction. PMID:27087470

Interaction of xenone difluoride with the fluorocomplexes of lanthanides and rubidium of the Rb3M3F6 composition

International Nuclear Information System (INIS)

Goryachenkov, S.A.; Fadeeva, N.E.; Kiselev, Yu.M.; Martynenko, L.I.; Spitsyn, V.I.

1984-01-01

The possibility of preparing rubidium fluorocomplexes of tetravalent lanthanides of the Rb 3 M 4 F 7 composition from Rb 3 M 3 F 6 (M 3 =Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb) with XeF 2 has been studied. By the DTA method it is shown that Ce and Pr salts are fluorinated respectively at approximately 100 and approximately 235 deg C with a noticeable exoeffect. Tb and Dy salts fluorination proceeds with considerable kinetic difficulties. The fluorination products composition, Rb 3 M 4 F 7 (M 4 =Ce, Pr, Tb, Dy) is confirmed by the methods of chemical, IR-spectroscopic and X-ray phase analyses. XeF 2 interaction with Rb 3 M 3 F 6 salts of other lanthanides up to 400 deg C has not been observed

Hydrothermal synthesis and luminescent properties of LnPO4:Tb,Bi (Ln=La,Gd) phosphors under UV/VUV excitation

International Nuclear Information System (INIS)

Wang Yuhua; Wu Chunfang; Wei Jie

2007-01-01

Monoclinic LnPO 4 :Tb,Bi (Ln=La,Gd) phosphors were prepared by hydrothermal reaction and their luminescent properties under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation were investigated. LaPO 4 :Tb,Bi phosphor and GdPO 4 :Tb phosphor showed the strongest emission intensity under 254 and 147 nm excitation, respectively, because of the different energy transfer models. In UV region, Bi 3+ absorbed most energy then transferred to Tb 3+ , but in VUV region it was the host which absorbed most energy and transferred to Tb 3+

Surfactant mediated hydrothermal synthesis, characterization and luminescent properties of GdPO{sub 4}: Ce{sup 3+}/Tb{sup 3+} @ GdPO{sub 4} core shell nanorods

Energy Technology Data Exchange (ETDEWEB)

Khajuria, Heena; Ladol, Jigmet; Khajuria, Sonika; Shah, Mohd Syed; Sheikh, H.N., E-mail: hnsheikh@rediffmail.com

2016-08-15

Highlights: • Core shell nanorods were synthesised by surfactant assisted hydrothermal method. • Morphology of core shell nanorods resembles those of core nanorods indicating coating of shell on cores. • More uniform and non-aggregated core shell nanorods were prepared in presence of surfactants. • Surfactant assisted prepared core shell nanorods show intense emission as compared to uncoated core nanorods. - Abstract: Core shell GdPO{sub 4}: Ce{sup 3+}/Tb{sup 3+} @ GdPO{sub 4} nanorods were synthesized via hydrothermal route in the presence of different surfactants [cetyltrimethyl ammonium bromide (CTAB) and Sodium dodecyl sulphate (SDS)]. The nanorods were characterized by powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and photoluminescence (PL) studies. The X-ray diffraction results indicate good crystallinity and effective doping in core and core shell nanorods. SEM and TEM micrographs show that all of the as prepared gadolinium phosphate products have rod like shape. The compositional analysis of GdPO{sub 4}: Ce{sup 3+}/Tb{sup 3+} core was done by EDS. The emission intensity of the GdPO{sub 4}: Ce{sup 3+}/Tb{sup 3+} @ GdPO{sub 4} core shell increased significantly with respect to those of GdPO{sub 4}: Ce{sup 3+}/Tb{sup 3+} core nanorods. The effect of surfactant on the uniformity, thickness and luminescence of the core shell nanorods was investigated.

Theoretical investigations on the magnetocaloric and barocaloric effects in Tb{sub y}Gd{sub (1−y)}Al{sub 2} series

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, P.O.; Alho, B.P.; Alvarenga, T.S.T.; Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A.Magnus G. [Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo – UNIFESP, 12231-280 São José dos Campos, SP (Brazil); Instituto Nacional de Metrologia, Qualidade e Tecnologia – INMETRO, 25250-020 Duque de Caxias, RJ (Brazil); Sousa, V.S.R. de; Caldas, A.; Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

2013-06-25

Highlights: ► Anisotropic magnetocaloric effect in in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ► Prediction of barocaloric effect in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ►An optimal hybrid magnetocaloric material using Tb{sub y}Gd{sub (1-y)}Al{sub 2} compounds. -- Abstract: We report the calculations on the magnetocaloric and barocaloric effects in ferromagnetic series Tb{sub y}Gd{sub (1−y)}Al{sub 2}. Our model includes the crystalline electrical field interaction, exchange interactions among Tb–Tb, Gd–Gd and Tb–Gd magnetic ions and the Zeeman effect for an anisotropic system. The lattice and electronic entropies were included in adiabatic processes. The magnetocaloric effect calculated for magnetic field changes along the easy magnetic direction 〈1 1 1〉 is in good agreement with the experimental data. Calculation along the hard magnetization direction 〈0 0 1〉 predicts anomalous magnetocaloric effect, which was ascribed to the spin reorientation processes. From the available experimental data of Curie temperature dependence on pressure, the exchange model parameters were scaled and the barocaloric effect was calculated.

Brillouin scattering on TbAsO4 and GdVO4

International Nuclear Information System (INIS)

Wehrle, H.

1975-01-01

Using a two-pass interferometer the set of elastic constants in TbAsO 4 was determined. On the basis of these constants the Debye temperature was evaluated for T→0. The crystallographic phase transition could not be demonstrated in either case (TbAsO 4 and TmAsO 4 ) because of small Brillouin-line intensity in the low-temperature region. The frequency shifts of the Brillouin lines detected in the case of GdVO 4 show an increase of 5% for the temperature change from room temperature to helium temperature. Assuming this dependence for TbAsO 4 , too, the Debye temperature is changed by 5%. (HPOE) [de

Synthesis and characterization of heterobinuclear (La-Zn, Pr-Zn, Nd-Zn, Sm-Zn, Eu-Zn, Gd-Zn, Tb-Zn, Dy-Zn) azine-bridged complexes

International Nuclear Information System (INIS)

Singh, Bachcha; Srivastav, A.K.; Singh, P.K.

1997-01-01

Zinc(II) complex of 2-acetylpyridine salicyl aldazine (Haps) of the type Zn(aps) 2 (H 2 O) 2 has been synthesised. The reaction of Zn(aps) 2 (H 2 O) 2 with lanthanide chlorides, LnCl 3 (where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) yields azine-bridged heterobinuclear complexes of the formulae LnCl 3 Zn(aps) 2 (H 2 O) 2 . These complexes have been characterized by elemental analyses, molecular weight, conductance (solid and solution) and magnetic susceptibility measurements, mass, IR and electronic spectral data. X-ray powder diffraction data indicate the tetragonal unit lattice for Zn(aps) 2 (H 2 O) 2 and PrCl 3 Zn(aps) 2 (H 2 O) 2 . (author)

Eu{sup 3+}/Tb{sup 3+} doped cubic BaGdF{sub 5} multifunctional nanophosphors: Multicolor tunable luminescence, energy transfer and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Li, Honglan; Liu, Guixia, E-mail: liuguixia22@163.com; Wang, Jinxian; Dong, Xiangting; Yu, Wensheng

2017-06-15

A series of BaGdF{sub 5}:Eu{sup 3+}/Tb{sup 3+} orange-green-yellow-white emitting nanophosphors (NPs) were successfully synthesized via hydrothermal method without assistance of any surfactant, catalyst, or template. The nanocrystals are in sphere-like morphology with an average size of approximately 46 nm. The quenching concentrations of Eu{sup 3+} and Tb{sup 3+} single doped BaGdF{sub 5} phosphors are 5.5% and 15%, respectively. The tunable color tone can be obtained in Eu{sup 3+} and Tb{sup 3+} co-doped BaGdF{sub 5} phosphors, the strong orange-white and green-yellow emissions can be seen in BaGdF{sub 5}:5.5%Eu{sup 3+}, y%Tb{sup 3+} and BaGdF{sub 5}:3.5%Tb{sup 3+}, x%Eu{sup 3+} phosphors, especially. More significantly, we realize the more standard white emission with a CIE chromaticity diagram point at (0.317, 0.321) and a lower correlated color temperature of 6979 K in the BaGdF{sub 5}: 5.5%Eu{sup 3+}, 4.5%Tb{sup 3+} sample. In addition, the energy transfer phenomenon from Tb{sup 3+} to Eu{sup 3+} ions is clearly observed in Tb{sup 3+}, Eu{sup 3+} co-doped BaGdF{sub 5} phosphors and the energy transfer efficiency can reach a maximum of 75%. Moreover, the as-prepared samples exhibit paramagnetic properties at room temperature. This type of multifunctional multicolor emitting nanophosphor has promising applications in the fields of full-color displays, biomedical science, MRI, and so on. - Graphical abstract: The cubic phase BaGdF{sub 5}:Eu{sup 3+}/Tb{sup 3+} sphere-like nanophosphors were prepared. Energy transfer mechanism, color-tunable emissions and magnetic properties of BaGdF{sub 5}:Eu{sup 3+}/Tb{sup 3+} have been studied, which could have promising applications in the fields of full-color displays, MRI and biomedical science, and so on.

Gibbs free energy of formation of liquid lanthanide-bismuth alloys

International Nuclear Information System (INIS)

Sheng Jiawei; Yamana, Hajimu; Moriyama, Hirotake

2001-01-01

The linear free energy relationship developed by Sverjensky and Molling provides a way to predict Gibbs free energies of liquid Ln-Bi alloys formation from the known thermodynamic properties of aqueous trivalent lanthanides (Ln 3(5(6+ ). The Ln-Bi alloys are divided into two isostructural families named as the LnBi 2 (Ln=La, Ce, Pr, Nd and Pm) and LnBi (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb). The calculated Gibbs free energy values are well agreed with experimental data

Magnetic properties of the filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 synthesized under high pressure

OpenAIRE

Sekine, C; Uchiumi, T; Shirotani, I; Matsuhira, kazuyuki; Sakakibara, T; Goto, T; Yagi, T

2000-01-01

We have succeeded in synthesizing filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 under high pressure. The magnetic properties of GdRu4P12 and TbRu4P12 have been studied by means of electrical resistivity, magnetic susceptibility, and magnetization measurements. Magnetic experiments suggest that the Gd and Tb ions in the compounds have trivalent state. The compound GdRu4P12 displays features that suggest the occurrence of antiferromagnetic ordering below TN=22 K. In TbRu4P1...

Determination of lanthanides in fossil samples using laser induced breakdown spectroscopy

International Nuclear Information System (INIS)

Anzano, J.M.; Lasheras, R.J.; Canudo, I.; Laguna, M.

2017-01-01

As being a fast, simple and relatively non-destructive analytical technique Laser-induced breakdown spectroscopy (LIBS) has a large variety of applications including the analysis of paleontological samples. In this work LIBS is employed for the quantitative determination of lanthanides (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Sm, Tb, Tm and Yb) in vertebrate fossil samples comprising teeth, disarticulated complete or fragmented bones, eggshell fragments, and coprolites of dinosaurs, mammals and crocodiles. For emission line data, standard AnalaR grade salts of lanthanides were used. The major components: iron, calcium, magnesium, silicon and aluminum in the samples were also determined. The analytical information may be helpful in studying the samples for their age, formation environment and other paleontological properties. (author)

X-ray excited photoluminescence near the giant resonance in solid-solution Gd(1-x)Tb(x)OCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd(1-x)Tb(x)F3.

Science.gov (United States)

Waetzig, Gregory R; Horrocks, Gregory A; Jude, Joshua W; Zuin, Lucia; Banerjee, Sarbajit

2016-01-14

Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb(3+) centers upon excitation in proximity to the giant resonance of the host Gd(3+) ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb(3+) centers upon X-ray excitation near the giant resonance of the host Gd(3+) ions.

Laser-plasma source parameters for Kr, Gd, and Tb ions at 6.6 nm

Energy Technology Data Exchange (ETDEWEB)

Masnavi, Majid; Szilagyi, John; Parchamy, Homaira; Richardson, Martin C. [The Townes Laser Institute, College of Optics and Photonics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816 (United States)

2013-04-22

There is increasing interest in extreme-ultraviolet (EUV) laser-based lamps for sub-10-nm lithography operating in the region of 6.6 nm. A collisional-radiative model is developed as a post-processor of a hydrodynamic code to investigate emission from resonance lines in Kr, Gd, and Tb ions under conditions typical for mass-limited EUV sources. The analysis reveals that maximum conversion efficiencies of Kr occur at 5 Multiplication-Sign 10{sup 10}W/cm{sup 2}, while for Gd and Tb it was Asymptotically-Equal-To 0.9%/2{pi}sr for laser intensities of (2-5) Multiplication-Sign 10{sup 12}W/cm{sup 2}.

Magneto, spectral and thermal studies of lanthanum and lanthanide(3) bromide and nitrate complexes of 2,2'bipyridine mono N-oxide

International Nuclear Information System (INIS)

Agarwal, R.K.

1988-01-01

Lanthanide(3) bromide and nitrate complexes of 2,2'-bipyridine mono N-oxide (BipyNO) having the composition Ln(BipyNO) 3 Br 3 and Ln(BipyNO) 2 (NO 3 ) 3 (Ln=La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Yb) have been prepared and characterized by means of conductance, molecular weight, magnetic and spectral studies. The ligand acts as a bidentate O,N-chelating agent. The coordination number nine or ten for lanthanide ions has been assigned to these complexes. 3 tabs., 25 refs. (author)

Magneto and spectral behaviour of lanthanide(III) perchlorate complexes of n-isonicotinamidoanisalaldimine

International Nuclear Information System (INIS)

Agarwal, R.K.; Agarwal, Himanshu; Sarin, R.K.

1996-01-01

A new series of lanthanide(III) perchlorate complexes of N-isonicotinamidoanisalaldimine (INH-SAL) with the general composition (Ln(INH-SAL) 4 )(ClO) 4 ) 3 (Ln=La, Pr, Nd, Sm, Gd, Tb or Dy) were synthesized and characterized by elemental analyses, conductance, molecular weight, infrared and electronic spectral data. INH-SAL acts as a bidentate (N, O) chelating agents. The tentative coordination number eight has been assigned. Thermal behaviour of some representative chelates has also been investigated. (author). 14 refs., 2 tabs

Blue and green emitting Ce3+ and Tb3+ codoped Gd2O3 nanophosphors

International Nuclear Information System (INIS)

Loitongbam, Romeo Singh; Singh, W. Rameshwor

2013-01-01

Tb 3+ doped Gd 2 O 3 nanoparticles of 4-10 nm in size were synthesized from nitrate precursors by urea hydrolysis method in ethylene glycol medium at low temperature of 140 ℃. Characteristic Tb 3+ ion green emission corresponding to 5 D 4 ’! 7 F J was observed to be very strong, which further increases with heat treatment temperature. Characteristic blue color emission of Ce 3+ ion transitions for 5 d’! 2 F 7/2 and 2 F 5/2 (at 422 nm and 485 nm respectively) was found to be very strong in as-synthesized Ce 0.06 Tb 0.14 Gd 0.8 O 3 nanoparticles. However, its luminescence intensity decreases with increase in heating temperature or increase in the particle size/crystallinity, whereas there was a weak emission peak of Tb 3+ ion at 545 nm. The polycrystalline nature of as-prepared sample change to highly crystalline state when heated at elevated temperature (900 ℃). (author)

A template-free solvothermal synthesis and photoluminescence properties of multicolor Gd2O2S:xTb3+, yEu3+ hollow spheres

Science.gov (United States)

Sang, Xiaotong; Xu, Guangxi; Lian, Jingbao; Wu, Nianchu; Zhang, Xue; He, Jiao

2018-06-01

The multicolor Gd2O2S:xTb3+, yEu3+ hollow spheres were successfully synthesized via a template-free solvothermal route without the use of surfactant from commercially available Ln (NO3)3·6H2O (Ln = Gd, Tb and Eu), absolute ethanol, ethanediamine and sublimed sulfur as the starting materials. The phase, structure, particle morphology and photoluminescence (PL) properties of the as-obtained products were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and photoluminescence spectra. The influence of synthetic time on phase, structure and morphology was systematically investigated and discussed. The possible formation mechanism depending on synthetic time t for the Gd2O2S phase has been presented. These results demonstrate that the Gd2O2S hollow spheres could be obtained under optimal condition, namely solvothermal temperature T = 220 °C and synthetic time t = 16 h. The as-obtained Gd2O2S sample possesses hollow sphere structure, which has a typical size of about 2.5 μm in diameter and about 0.5 μm in shell thickness. PL spectroscopy reveals that the strongest emission peak for the Gd2O2S:xTb3+ and the Gd2O2S:yEu3+ samples is located at 545 nm and 628 nm, corresponding to 5D4→7F5 transitions of Tb3+ ions and 5D0→7F2 transitions of Eu3+ ions, respectively. The quenching concentration of Tb3+ ions and Eu3+ ions is 7%. In the case of Tb3+ and Eu3+ co-doped samples, when the concentration of Tb3+ or Eu3+ ions is 7%, the optimum concentration of Eu3+ or Tb3+ ions is determined to be 1%. Under 254 nm ultraviolet (UV) light excitation, the Gd2O2S:7%Tb3+, the Gd2O2S:7%Tb3+,1%Eu3+ and the Gd2O2S:7%Eu3+ samples give green, yellow and red light emissions, respectively. And the corresponding CIE coordinates vary from (0.3513, 0.5615), (0.4120, 0.4588) to (0.5868, 0.3023), which is also well consistent with their luminous photographs.

Gas-Phase Reactions of Doubly Charged Lanthanide Cations with Alkanes and Alkenes. Trends in Metal(2+) Reactivity

Energy Technology Data Exchange (ETDEWEB)

Gibson, John K.; Marcalo, Joaquim; Santos, Marta; Pires de Matos, Antonio; Haire, Richard G.

2008-12-08

The gas-phase reactivity of doubly-charged lanthanide cations, Ln2+ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), with alkanes (methane, ethane, propane, n-butane) and alkenes (ethene, propene, 1-butene) was studied by Fourier transform ion cyclotron resonance mass spectrometry. The reaction products consisted of different combinations of doubly-charged organometallic ions?adducts or species formed via metal-ion-induced hydrogen, dihydrogen, alkyl, or alkane eliminations from the hydrocarbons?and singly-charged ions that resulted from electron, hydride, or methide transfers from the hydrocarbons to the metal ions. The only lanthanide cations capable of activating the hydrocarbons to form doubly-charged organometallic ions were La2+, Ce2+, Gd2+, and Tb2+, which have ground-state or low-lying d1 electronic configurations. Lu2+, with an accessible d1 electronic configuration but a rather high electron affinity, reacted only through transfer channels. The remaining Ln2+ reacted via transfer channels or adduct formation. The different accessibilities of d1 electronic configurations and the range of electron affinities of the Ln2+ cations allowed for a detailed analysis of the trends for metal(2+) reactivity and the conditions for occurrence of bond activation, adduct formation, and electron, hydride, and methide transfers.

Optimization of the radio lanthanides separation device; Optimizacion de dispositivo para separacion de radiolantanidos

Energy Technology Data Exchange (ETDEWEB)

Vera T, A. L.

2009-07-01

At present, cancer is a major cause of mortality in our country, therefore, its prevention, diagnosis and treatment are vital to health systems. The cancer treatment and other diseases, from monoclonal antibodies, peptides, or amino macro aggregates marked with beta particle emitting radionuclides, is a highly promising field. The radioactive lanthanides: Pm, Tb, Ho, and Lu are beta emitters, which possess nuclear and chemical properties, which have shown their feasibility as radioisotopes of radiotherapeutic use. However, these radioisotopes are not available commercially in this connection, the Research Laboratory of Radioactive Materials of the National Institute of Nuclear Research, has developed the methodology of production of these radioisotopes and based on this work is designed, constructed and installed the radio lanthanides separation device for the radioisotopes production routinely. This device is part of the cell, , which has and auxiliary air service, an extraction system and is protected with a 10 cm of lead shielding. The radio lanthanides separation device is manual and easy to handle. The main function of this equipment is the radio lanthanides separation from extractive chromatography through packed columns with a commercial resin (Ln SPS) and coated on the top and bottom by fiberglass. The radio lanthanides separation device comprises a main carrousel where the separation columns and elution containers are mounted. It also has a system of open irradiation vials, carrier samples for columns and glassware. This paper presents a detailed description of the radio lanthanides separation device and its management, which allows the radioisotopes production Pm, Tb, Ho, and Lu from the separation of its parents Nd, Dy, Gd, and Yb respectively. (Author)

RNi{sub 8}Si{sub 3} (R=Gd,Tb): Novel ternary ordered derivatives of the BaCd{sub 11} type

Energy Technology Data Exchange (ETDEWEB)

Pani, M., E-mail: marcella@chimica.unige.it [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, Moscow, GSP-2 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Provino, A.; Manfrinetti, P. [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

2016-01-15

The title compounds have been synthesized and characterized both from the structural and magnetic point of view. Both crystallize in a new monoclinic structure strictly related to the tetragonal BaCd{sub 11} type. The structure was solved by means of X-ray single-crystal techniques for GdNi{sub 8}Si{sub 3} and confirmed for TbNi{sub 8}Si{sub 3} on powder data; the corresponding lattice parameters (obtained from Guinier powder patterns) are a=6.3259(2), b=13.7245(5), c=7.4949(3) Å, β=113.522(3)°, V{sub cell}=596.64(3) Å{sup 3} and a=6.3200(2), b=13.6987(4), c=7.4923(2) Å, β=113.494(2)°, V{sub cell}=594.88(2) Å{sup 3}. The symmetry relationship between the tI48-I4{sub 1}/amd BaCd{sub 11} aristotype and the new ordered mS48-C2/c GdNi{sub 8}Si{sub 3} derivative is described via the Bärnighausen formalism within the group theory. The large Gd–Gd (Tb–Tb) distances, mediated via Ni–Si network, likely lead to weak magnetic interactions. Low-field magnetization vs temperature measurements indicate weak and field-sensitive antiferromagnetic ground state, with ordering temperatures of 3 K in GdNi{sub 8}Si{sub 3} and about 2–3 K in TbNi{sub 8}Si{sub 3}. On the other hand, the isothermal field-dependent magnetization data show the presence of competing interactions in both compounds, with a field-induced ferromagnetic behavior for GdNi{sub 8}Si{sub 3} and a ferrimagnetic-like behavior in TbNi{sub 8}Si{sub 3} at the ordering temperature T{sub C/N} of about (or slightly higher than) 3K. The magnetocaloric effect, quantified in terms of isothermal magnetic entropy change ΔS{sub m}, has the maximum values of –19.8 J(kg K){sup −1} (at 4 K for 140 kOe field change) and −12.1 J(kg K){sup −1} (at 12 K for 140 kOe field change) in GdNi{sub 8}Si{sub 3} and TbNi{sub 8}Si{sub 3}, respectively. - Graphical abstract: GdNi{sub 8}Si{sub 3} and TbNi{sub 8}Si{sub 3} compounds are isostructural, and crystallize in a new monoclinic type strictly related to the tetragonal

Interaction of xenon difluoride with the fluorocomplexes of lanthanides and rubidium of the Rb/sub 3/M/sup 3/F/sub 6/ composition

Energy Technology Data Exchange (ETDEWEB)

Goryachenkov, S.A.; Fadeeva, N.E.; Kiselev, Yu.M.; Martynenko, L.I.; Spitsyn, V.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

The possibility of preparing rubidium fluorocomplexes of tetravalent lanthanides of the Rb/sub 3/M/sup 4/F/sub 7/ composition from Rb/sub 3/M/sup 3/F/sub 6/ (M/sup 3/=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb) with XeF/sub 2/ has been studied. By the DTA method it is shown that Ce and Pr salts are fluorinated respectively at approximately 100 and approximately 235 deg C with a noticeable exoeffect. Tb and Dy salts fluorination proceeds with considerable kinetic difficulties. The fluorination products composition, Rb/sub 3/M/sup 4/F/sub 7/ (M/sup 4/=Ce, Pr, Tb, Dy) is confirmed by the methods of chemical, IR-spectroscopic and X-ray phase analyses. XeF/sub 2/ interaction with Rb/sub 3/M/sup 3/F/sub 6/ salts of other lanthanides up to 400 deg C has not been observed.

Lanthanide Organophosphate Spiro Polymers: Synthesis, Structure, and Magnetocaloric Effect in the Gadolinium Polymer.

Science.gov (United States)

Gupta, Sandeep K; Bhat, Gulzar A; Murugavel, Ramaswamy

2017-08-07

Spirocyclic lanthanide organophosphate polymers, {[Ln(dipp)(dippH)(CH 3 OH)(H 2 O) 2 ](CH 3 OH) 2 } n [Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Ho (10), Er (11)], have been prepared from the reaction of Ln(NO 3 ) 3 ·xH 2 O with sterically hindered 2,6-diisopropylphenyl phosphate (dippH 2 ) using aqueous NaOH as the base. The one-dimensional chainlike lanthanide (III) organophosphate coordination polymers have been characterized with the aid of analytical and spectroscopic methods. The single crystal structure determination of polymers (2-5 and 7-11) reveals that in these compounds the hydrophobic organic groups of the phosphate provide a protective coating for the inorganic lanthanide phosphate polymeric chain. The encapsulation of inorganic lanthanide phosphate core, which has very low solubility product, within the organic groups assists in the facile crystallization of the polymers. The di- and monoanionic organophosphate ligands dipp 2- and dippH - display [2.111] and [2.110] binding modes, respectively, in 2-5 and 7. However, they exhibit only [2.110] binding mode in the case of 8-11. This results in the formation of two different types of polymers. While the lighter rare-earth metal ions in 2-5 and 7 display eight coordinate biaugmented trigonal prismatic geometry, the heavier rare-earth metal ions in 9-11 exhibit a seven coordinate capped trigonal prismatic environment. The Tb(III) ion in 8 displays distorted pentagonal bipyramidal geometry. Magnetic studies reveal the presence of weak antiferromagnetic interactions between the Ln(III) ions through the organophosphate ligand. The isotropic Gd(III) polymer 7 exhibits a maximum entropy change of 17.83 J kg -1 K -1 for a field change of 7.0 T at 2.5 K, which is significant considering the high molecular weight of the organophosphate ligand. These polymers represent the first family of any structurally characterized rare-earth organophosphate polymers derived from monoesters

Synthesis, crystal structure and luminescent properties of lanthanide extended structure with asymmetrical dinuclear units based on 2-(methylthio)benzoic acid

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Cristiane K.; Souza, Viviane P. de; Luz, Leonis L. da [Departamento de Química Fundamental, UFPE, 50.740-560 Recife, PE (Brazil); Menezes Vicenti, Juliano R. de [Escola de Química e Alimento, FURG, 96203-900 Rio Grande, RS (Brazil); Burrow, Robert A. [Departamento de Química, UFSM, 97105-900 Santa Maria, RS (Brazil); Severino Alves; Longo, Ricardo L. [Departamento de Química Fundamental, UFPE, 50.740-560 Recife, PE (Brazil); Malvestiti, Ivani, E-mail: ivani@ufpe.br [Departamento de Química Fundamental, UFPE, 50.740-560 Recife, PE (Brazil)

2016-02-15

The extended structures [Ln{sub 2}(L){sub 6}(OH{sub 2}){sub 4}] with L=2-(methylthio)benzoato (2-CH{sub 3}S–C{sub 6}H{sub 4}COO{sup −}) and Ln=Tb (1), Eu (2) and Gd (3) were successfully synthesized and characterized. The single crystal structure of compound 1 was determined and showed an extended structure made up of asymmetrical dinuclear units with the formula catena-poly[{Tb(H_2O)_4}-(μ-L-1κO:2κO'){sub 2}-{Tb(L-κO,O')_2}-(μ-L-1κO:2κO'){sub 2}]. In the molecule of 1, there are two distinct metal sites. The Tb atom in site 1 is bound to four coordinated water molecules and four oxygen atoms from four different benzoate ligands, two of which bridge to site 2 Tb atoms on one side and two to site 2 Tb atoms on the other side. The site 2 Tb atom is bound to four oxygen atoms from two chelating benzoate ligands and four oxygen atoms from four different benzoate ligands, two of which bridge to site 1 Tb atoms on one side and two to site 1 Tb atoms on the other side. The bridging benzoate ligands extend the framework in one-dimension with alternating site 1/site 2 Tb atoms. The luminescent properties of these asymmetric dinuclear extended structures are quite peculiar and showed a single emitting lanthanide center. The quantum yields of 1 (ca. 50–55%) is practically independent of the excitation energy, whereas those of 2 are vanishing small (<1%) when excited at the ligand states and become sizable (ca. 10–20%) upon excitation at the intra-4f manifold. To reconcile these experimental observations in conjunction with the spectral data for compounds 1 and 3, a strong interaction between the lanthanide emitting states at sites 1 and 2 was proposed. For compound 1, the numerical solutions of the rate equations provided evidences that when the transition rates between the emitting states at both sites are larger than the highest decaying rate of these states, the system becomes an effective single emitter. This establishes, for the first time

Rare Earth Chalcogels NaLnSnS4 (Ln = Y, Gd, Tb) for Selective Adsorption of Volatile Hydrocarbons and Gases

KAUST Repository

Edhaim, Fatimah

2017-06-28

The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS4, NaGdSnS4, and NaTbSnS4 is reported. Rare earth metal ions like Y3+, Gd3+, and Tb3+ react with the chalcogenide clusters [SnS4]4– in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m2·g–1 (NaYSnS4), 479 m2·g–1 (NaGdSnS4), and 354 m2·g–1 (NaTbSnS4). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2–50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO2 over CH4 or H2. The notable adsorption capacity for toluene (NaYSnS4: 1108 mg·g–1; NaGdSnS4: 921 mg·g–1; and NaTbSnS4: 645 mg·g–1) and high selectivity for gases (CO2/H2: 172 and CO2/CH4: 50 for NaYSnS4, CO2/H2: 155 and CO2/CH4: 37 for NaGdSnS4, and CO2/H2: 75 and CO2/CH4: 28 for NaTbSnS4) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes.

Ion-irradiation resistance of the orthorhombic Ln_2TiO_5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) series

International Nuclear Information System (INIS)

Aughterson, Robert D.; Lumpkin, Gregory R.; Ionescu, Mihail; Reyes, Massey de los; Gault, Baptiste; Whittle, Karl R.; Smith, Katherine L.; Cairney, Julie M.

2015-01-01

The response of Ln_2TiO_5 (where Ln is a lanthanide) compounds exposed to high-energy ions was used to test their suitability for nuclear-based applications, under two different but complementary conditions. Eight samples with nominal stoichiometry Ln_2TiO_5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy), of orthorhombic (Pnma) structure were irradiated, at various temperatures, with 1 MeV Kr"2"+ ions in-situ within a transmission electron microscope. In each case, the fluence was increased until a phase transition from crystalline to amorphous was observed, termed critical dose D_c. At certain elevated temperatures, the crystallinity was maintained irrespective of fluence. The critical temperature for maintaining crystallinity, T_c, varied non-uniformly across the series. The T_c was consistently high for La, Pr, Nd and Sm_2TiO_5 before sequential improvement from Eu to Dy_2TiO_5 with T_c's dropping from 974 K to 712 K. In addition, bulk Dy_2TiO_5 was irradiated with 12 MeV Au"+ ions at 300 K, 723 K and 823 K and monitored via grazing-incidence X-ray diffraction (GIXRD). At 300 K, only amorphisation is observed, with no transition to other structures, whilst at higher temperatures, specimens retained their original structure. The improved radiation tolerance of compounds containing smaller lanthanides has previously been attributed to their ability to form radiation-induced phase transitions. No such transitions were observed here. - Highlights: • First ion-irradiation studies on a number of novel compounds including Pr_2TiO_5, Eu_2TiO_5 and Tb_2TiO_5. • Systematic in-situ ion-irradiation study of almost complete Ln_2TiO_5 series (Ln = lanthanides) with orthorhombic crystal structure type. • The first grazing incidence study of bulk irradiated Dy_2TiO_5 looking for irradiation induced phase transition.

Crystal structures and some physical properties of perovskite type vanadites of lanthanide-series elements

Energy Technology Data Exchange (ETDEWEB)

Shinike, T [Osaka Dental Coll., Hirakata (Japan); Adachi, G; Shiokawa, J

1980-04-01

Crystal structures and some physical properties of the perovskite type vanadites of the lanthanide-series elements were studied. LaVO/sub 3/ and CeVO/sub 3/ had a tetragonal unit cell and other compounds studied were isostructural with orthorhombic GdFeO/sub 3/. The conductivity of all compounds showed semiconductive behavior with an activation energy about 0.1 eV. Electrical conductivity at room temperature decreased along the series from LaVO/sub 3/ to GdVO/sub 3/, and quasiconstant values were observed from TbVO/sub 3/ to LuVO/sub 3/. All the compounds studied, with the exception of LaVO/sub 3/, SmVO/sub 3/ and GdVO/sub 3/, were antiferromagnets with a weak ferromagnetism because of antisymmetric exchange interaction at low temperatures. At high temperature, all the compounds showed paragnetism.

Host-Sensitized and Tunable Luminescence of GdNbO4:Ln3+ (Ln3+ = Eu3+/Tb3+/Tm3+) Nanocrystalline Phosphors with Abundant Color.

Science.gov (United States)

Liu, Xiaoming; Chen, Chen; Li, Shuailong; Dai, Yuhua; Guo, Huiqin; Tang, Xinghua; Xie, Yu; Yan, Liushui

2016-10-17

Up to now, GdNbO 4 has always been regarded as an essentially inert material in the visible region with excitation of UV light and electron beams. Nevertheless, here we demonstrate a new recreating blue emission of GdNbO 4 nanocrystalline phosphors with a quantum efficiency of 41.6% and host sensitized luminescence in GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors with abundant color in response to UV light and electron beams. The GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors were synthesized by a Pechini-type sol-gel process. With excitation of UV light and low-voltage electron beams, the obtained GdNbO 4 nanocrystalline phosphor presents a strong blue luminescence from 280 to 650 nm centered around 440 nm, and the GdNbO 4 :Ln 3+ nanocrystalline phosphors show both host emission and respective emission lines derived from the characterize f-f transitions of the doping Eu 3+ , Tb 3+ , and Tm 3+ ions. The luminescence color of GdNbO 4 :Ln 3+ nanocrystalline phosphors can be tuned from blue to green, red, blue-green, orange, pinkish, white, etc. by varying the doping species, concentration, and relative ratio of the codoping rare earth ions in GdNbO 4 host lattice. A single-phase white-light-emission has been realized in Eu 3+ /Tb 3+ /Tm 3+ triply doped GdNbO 4 nanocrystalline phosphors. The luminescence properties and mechanisms of GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) are updated.

Some high coordination compounds of lanthanides(III derived from N-isonicotinamidosalicyaldimine

Directory of Open Access Journals (Sweden)

Ram K. Agarwal

2000-12-01

Full Text Available A new series of lanthanide(III nitrates, isothiocyanates and perchlorates coordination complexes of N-isonicotinamidosalicyaldimine (INH-SAL with the general composition LnX3.n(INH-SAL (Ln = La, Pr, Nd, Sm, Gd, Tb or Dy; X = NO3-, n = 2; X = NCS-, n = 2 or 3 and X = ClO4-, n = 4 have been reported. All the complexes were characterized by chemical analyses, conductance, molar weight, magnetic moment measurements, infrared and electronic spectra. IR spectra indicate that the ligand behaves as a neutral N,O-donors. Thermal properties of the complexes have also been studied.

Syntheses and crystal structures of BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Prakash, Jai; Beard, Jessica C.; Ibers, James A. [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); Mesbah, Adel [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); ICSM-UMR 5257 CNRS/CEA/UM2/ENSCM, Bat 426, BP 17171, 30207 Bagnols/Ceze (France)

2015-06-15

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}, were synthesized by the reactions of the elements at 1173-1273 K. For CsAgUTe{sub 3} CsCl flux was used. Their crystal structures were determined by single-crystal X-ray diffraction studies. The sulfide BaAgTbS{sub 3} crystallizes in the BaAgErS{sub 3} structure type in the monoclinic space group C{sup 3},{sub 2h}-C2/m, whereas the tellurides BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3} crystallize in the KCuZrS{sub 3} structure type in the orthorhombic space group D{sup 1},{sub 2}{sup 7},{sub h}-Cmcm. The BaAgTbS{sub 3} structure consists of edge-sharing [TbS{sub 6}{sup 9-}] octahedra and [AgS{sub 5}{sup 9-}] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features {sup 2}{sub ∞}[MLnTe{sub 3}{sup 2-}] layers for BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and {sup 2}{sub ∞}[AgUTe{sub 3}{sup 1-}] layers for CsAgUTe{sub 3}. These layers comprise [MTe{sub 4}] tetrahedra and [LnTe{sub 6}] or [UTe{sub 6}] octahedra. Ba or Cs atoms separate these layers. As there are no short Q..Q (Q = S or Te) interactions these compounds achieve charge balance as Ba{sup 2+}M{sup +}Ln{sup 3+}(Q{sup 2-}){sub 3} (Q = S and Te) and Cs{sup +}Ag{sup +}U{sup 4+}(Te{sup 2-}){sub 3}. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

In vivo radiochemical properties of Tb-149: A new radiolanthanide for targeted cancer therapy

International Nuclear Information System (INIS)

Allen, B.J.; Beyer, G.J.; Morel, C.H.; Aleksandrova, Y.; Jahn, S.

1996-01-01

Full text: 149 Tb (4.15 h) decays by the emission of both 3.9 MeV alpha particles (17% branching) and positrons (4% branch), and uniquely combines both therapeutic and PET diagnostic properties. In this paper we report the production route, systemic studies of radio-lanthanides with ethylenediaminetetra methylene phosphonate (EDTMP) ligand, and the first 149 Tb phantom studies using PET. The radio-lanthanides used in this study were produced at the ISOLDE (isotope separator on-line) facility at CERN. They are produced carrier free, isotopically and chemically separated (isobaric separation using cation exchange chromatography) in a form suitable for protein labelling. Batches up to 20 mCi of 1 4 9T b are available. We have established relationships between biokinetics, EDTMP concentration, and the ionic radius of the radiolanthanide used. The tumour to liver ratio in mice reaches a maximum value at 1 mM 10 mM and decreases from 10 by almost two decades according to the ionic radius of the lanthanide. For Tb, a tumour to liver ratio of 5 can be obtained, similar to Gd. No significant differences in the uptake in bone for all lanthanides in the EDTMP system were observed. A fast blood clearance allows clear bone images to be obtained via PET at 60-90 min post-injection, as shown with rabbits using 142 Sm-EDTMP. The first phantom PET studies with 149 Tb are also reported. We conclude that the fast biokinetics and the alpha decay mode open up new possibilities for a more efficient endo-radionuclide therapy using EDTMP. The high purity of the 149T b (isotopically separated and carrier free) produced in this way makes it very suitable for the labelling of octretides

Superdeformed bands in /sup 150/Gd and /sup 151/Tb: Evidence for the influence of high-N intruder states at large deformations

Energy Technology Data Exchange (ETDEWEB)

Fallon, P.; Alderson, A.; Bentley, M.A.; Bruce, A.M.; Forsyth, P.D.; Howe, D.; Roberts, J.W.; Sharpey-Schafer, J.F.; Twin, P.J.; Beck, F.A.

1989-02-16

Rotational bands, characteristic of a superdeformed prolate shape (epsilon approx. = 0.6) and extending to above spin 60 Planck constant, have been observed in both /sup 150/Gd and /sup 151/Tb. The magnitudes of the moments of inertia I/sup (2)/ were found to vary with frequency and the variation greatly exceeded that seen in /sup 148,149/Gd and /sup 151,152/Dy. The differences in the I/sup (2)/'s are attributed to the occupation of particular high-N orbitals. Moreover, contrary to the previous examples the bands in both /sup 150/Gd and /sup 151/Tb de-excited at a much higher rotational frequency of Planck constant..omega.. approx. = 0.4 MeV and this may indicate that the pair gap extends to higher frequencies in /sup 150/Gd and /sup 151/Tb.

Study of the influence of the codopant over the photoluminescent properties of PAA doped with Eu3+, Gd3+, and Tb3+

International Nuclear Information System (INIS)

Flores, M.; Arroyo, R.

2003-01-01

The results are presented obtained about the synthesis of acrylic poly acid characterization (PAA) doped with Eu 3+ , Gd 3+ and Tb 3+ . They got ready materials with even of these ions and it was studied the influence of the co dopant in the processes of emission of Eu 3+ (λ em = 618 nm), Gd 3+ (λ em = 624 nm) and Tb 3+ (λ em = 546 nm), as well as their effect in the phosphorescence (λ em = 450 nm) of the polymeric matrix. It was found that the intensity of the emission of Eu 3+ diminishes substantially due to the presence of the ions Gd 3+ , contrary to what happens when the co dopant is Tb 3+ , which causes an increase. In the one case of the emission of Tb 3+ , this it increases with the presence of Gd 3+ but it diminishes when Eu 3+ is present. These results are consequence of the homogeneous distribution of those dopants and of the phenomena of energy transfer that happen in the materials synthesized. (Author)

A study of luminescence from Eu"3"+, Ce"3"+, Tb"3"+ and Ce"3"+/Tb"3"+ in new potassium gadolinium phosphate K_3Gd_5(PO_4)_6

International Nuclear Information System (INIS)

Meng, Fangui; Zhang, Hongzhi; Chen, Cuili; Kim, Sun Il; Seo, Hyo Jin; Zhang, Xinmin

2016-01-01

New potassium gadolinium phosphate [K_3Gd_5(PO_4)_6] doped with Eu"3"+, Ce"3"+, Tb"3"+ and co-doped with Ce"3"+ and Tb"3"+ phosphors were prepared by high temperature solid state synthesis. Phase purity of the powders was checked by X-ray powder diffraction. Luminescence and excitation spectra of samples were reported. In particular, the interaction mechanism between Eu"3"+ ions was investigated in terms of the Inokuti–Hirayama model; it was found that the interactions between Eu"3"+ can be assigned to dipole–dipole interaction. K_3Gd_5(PO_4)_6:Eu"3"+ could act as a candidate for solid state lighting due to its strong absorption band in the near-UV region (350–400 nm). The energy transfer from Ce"3"+ to Tb"3"+ was confirmed and the mechanism was studied using Dexter's theory; it is concluded that electric dipole–dipole interaction predominates in the energy transfer process from Ce"3"+ to Tb"3"+ in the K_3Gd_5(PO_4)_6 host. The energy transfer efficiency and critical distance were also investigated. - Highlights: • Optical properties of K_3Gd_5(PO_4)_6:RE"3"+ are investigated for the first time. • The interaction mechanism between Eu"3"+ ions is attributed to dipole–dipole type. • K_3Eu_5(PO_4)_6 is a candidate phosphor for application to solid state lighting. • There exists an efficient energy transfer from Ce"3"+ to Tb"3"+ (η is up to 95%). • The mechanism of energy transfer process is electric dipole–dipole interaction.

Radioluminescence studies of colloidal oleate-capped β-Na(Gd,Lu)F4:Ln3+ nanoparticles (Ln = Ce, Eu, Tb).

Science.gov (United States)

Cooper, Daniel R; Capobianco, John A; Seuntjens, Jan

2018-04-26

We report on the synthesis, characterization, and radioluminescence quantification of several new varieties of nanoparticles with the general composition β-NaLnF4, incorporating known luminescent activator/sensitizer pairs. Using Monte Carlo modeling to complement luminescence measurements, we have calculated the radioluminescence yields and intrinsic conversion efficiencies of colloidally-dispersed nanoparticles by comparison to an organic liquid scintillator. While five of the compositions had low to modest radioluminescence yields relative to bulk materials, colloidal β-Na(Lu0.65Gd0.2Tb0.15)F4 displayed a strong output of 39 460 photons per MeV absorbed, comparable to some of the best non-hygroscopic bulk crystal scintillators and X-ray phosphors such as Gd2O2S:Tb. Measurements of β-Na(Lu0.65Gd0.2Tb0.15)F4 powder samples revealed persistent luminescence as well as stable charge trapping, warranting further investigation.

Lanthanide-activated Na5Gd9F32 nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

International Nuclear Information System (INIS)

Chen, Daqin; Wan, Zhongyi; Zhou, Yang; Chen, Yan; Yu, Hua; Lu, Hongwei; Ji, Zhenguo; Huang, Ping

2015-01-01

Highlights: • Na 5 Gd 9 F 32 nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na 5 Gd 9 F 32 lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na 5 Gd 9 F 32 nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na 5 Gd 9 F 32 lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb 3+ /Er 3+ ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties

Optical and magneto-optical characterization of TbFeCo and GdFeCo thin films for high-density recording

International Nuclear Information System (INIS)

Hendren, W R; Atkinson, R; Pollard, R J; Salter, I W; Wright, C D; Clegg, W W; Jenkins, D F L

2003-01-01

Thin, optically semi-infinite films of amorphous TbFeCo and GdFeCo, suitable for magneto-optical recording, have been deposited by DC magnetron sputtering onto glass. Ellipsometric techniques have been used to determine the complex refractive index and complex magneto-optical parameter of the films in the wavelength range 400-900 nm, thus characterizing the materials. A review of the literature is presented and shows that the results for the TbFeCo films compare favourably with published results obtained from measurements conducted in situ, with the films protected with ZnS barrier layers. It is found that GdFeCo and TbFeCo are optically very similar, but magneto-optically the materials are quite different

Optical and magneto-optical characterization of TbFeCo and GdFeCo thin films for high-density recording

Energy Technology Data Exchange (ETDEWEB)

Hendren, W R [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Atkinson, R [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Pollard, R J [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Salter, I W [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Wright, C D [School of Engineering and Computer Science, University of Exeter, Exeter EX4 4QF (United Kingdom); Clegg, W W [CRIST, University of Plymouth, Plymouth PL4 8AA (United Kingdom); Jenkins, D F L [CRIST, University of Plymouth, Plymouth PL4 8AA (United Kingdom)

2003-03-12

Thin, optically semi-infinite films of amorphous TbFeCo and GdFeCo, suitable for magneto-optical recording, have been deposited by DC magnetron sputtering onto glass. Ellipsometric techniques have been used to determine the complex refractive index and complex magneto-optical parameter of the films in the wavelength range 400-900 nm, thus characterizing the materials. A review of the literature is presented and shows that the results for the TbFeCo films compare favourably with published results obtained from measurements conducted in situ, with the films protected with ZnS barrier layers. It is found that GdFeCo and TbFeCo are optically very similar, but magneto-optically the materials are quite different.

Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS.

Science.gov (United States)

Bentlin, Fabrina R S; dos Santos, Clarissa M M; Flores, Erico M M; Pozebon, Dirce

2012-01-13

This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L(-1), respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration. Copyright © 2011 Elsevier B.V. All rights reserved.

Study of the influence of the codopant over the photoluminescent properties of PAA doped with Eu{sup 3+}, Gd{sup 3+}, and Tb{sup 3+}; Estudio de la influencia del codopante sobre las propiedades fotoluminiscentes de PAA dopado con Eu{sup 3+}, Gd{sup 3+} y Tb{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Flores, M.; Arroyo, R. [Departamento de Fisica, UAM-I, A.P. 55-534, 09820 Mexico D.F. (Mexico)

2003-07-01

The results are presented obtained about the synthesis of acrylic poly acid characterization (PAA) doped with Eu{sup 3+}, Gd{sup 3+} and Tb{sup 3+}. They got ready materials with even of these ions and it was studied the influence of the co dopant in the processes of emission of Eu{sup 3+} ({lambda}{sub em} = 618 nm), Gd{sup 3+} ({lambda}{sub em} = 624 nm) and Tb{sup 3+} ({lambda}{sub em} = 546 nm), as well as their effect in the phosphorescence ({lambda}{sub em} = 450 nm) of the polymeric matrix. It was found that the intensity of the emission of Eu{sup 3+} diminishes substantially due to the presence of the ions Gd{sup 3+}, contrary to what happens when the co dopant is Tb{sup 3+} , which causes an increase. In the one case of the emission of Tb{sup 3+}, this it increases with the presence of Gd{sup 3+} but it diminishes when Eu{sup 3+} is present. These results are consequence of the homogeneous distribution of those dopants and of the phenomena of energy transfer that happen in the materials synthesized. (Author)

Studies on the electrochemical behavior of heavy lanthanide ions and the synthesis, characterization of heavy metal chelate complexes

International Nuclear Information System (INIS)

Kang, Sam Woo; Chang, Choo Hwan; Son, Byung Chan; Suh, Moo Yul; Kim, Chae Kyun

1991-01-01

Electrochemical behavior of some heavy lanthanide ions(Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ and Lu 3+ ) in various supporting electrolytes has been investigated by dc polarography, differential pulse polarography and cyclic voltammetry. The peak potentials and the peak currents, their dependency on the concentration and pH effects, the reversibility of the electrode reactions are described. The reduction of Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ and Lu 3+ ions in 0.1M lithium chloride solution proceeds by a three-electron change directly to the metallic state, whereas the reduction of Yb 3+ proceeds by a one-electron change followed by a two-electron change. It was found that, in differential pulse polarography and cyclic voltammetry, the peak potential, peak current and current function showed constant value in the pH range of 4.0-6.0 by varying pH and scan rates. And also the current function is found to decrease as the sweep rate is increased when the pH reaches 4.0. This fact may indicate a chemical reaction coupled with the electrochemical reaction at lower pH values(pH 3+ ion is possible to determine voltammetrically within the error of ±3.5% in the presence of other competitive lanthanide ions. (Author)

Effect of rapid quenching on the magnetism and magnetocaloric effect of equiatomic rare earth intermetallic compounds RNi (R = Gd, Tb and Ho)

Energy Technology Data Exchange (ETDEWEB)

Rajivgandhi, R. [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Arout Chelvane, J. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Quezado, S.; Malik, S.K. [Departamento de F’ısica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59072-970 (Brazil); Nirmala, R., E-mail: nirmala@physics.iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India)

2017-07-01

Highlights: • Melt-spinning yields microcrystalline RNi (R = Gd, Tb and Ho) samples with texture. • The texture-induced anisotropy affects magnetic and magnetocaloric properties. • Melt-spinning helps one engineer magnetocaloric effect in rare-earth compounds. - Abstract: Magnetocaloric effect (MCE) in RNi (where R = Gd, Tb and Ho) compounds has been studied in their arc-melted and melt-spun forms. The compound GdNi has the orthorhombic CrB-type structure (Space group Cmcm, No. 63) and the compound HoNi has the orthorhombic FeB-type structure (Space group Pnma, No. 62) at room temperature regardless of their synthesis condition. However, arc-melted TbNi orders in a monoclinic structure (Space group P2{sub 1}/m, No. 11) and when it is rapidly quenched to a melt-spun form, it crystallizes in an orthorhombic structure (Space group Pnma, No. 62). The arc-melted GdNi, TbNi and HoNi compounds order ferromagnetically at ∼69 K, ∼67 K and ∼36 K (T{sub C}) respectively. While the melt-spun GdNi shows about 6 K increase in T{sub C}, the ordering temperature of TbNi remains nearly the same in both arc-melted and melt-spun forms. In contrast, a reduction in T{sub C} by about 8 K is observed in melt-spun HoNi, when compared to its arc-melted counterpart. Isothermal magnetic entropy change, ∆S{sub m}, calculated from the field dependent magnetization data indicates an enhanced relative cooling power (RCP) for melt-spun GdNi for field changes of 20 kOe and 50 kOe. A lowered RCP value is observed in melt-spun TbNi and HoNi. These changes could have resulted from the competing shape anisotropy and the granular microstructure induced by the melt-spinning process. Tailoring the MCE of rare earth intermetallic compounds by suitably controlled synthesis techniques is certainly one of the directions to go forward in the search of giant magnetocaloric materials.

Photoluminescent lanthanide-organic bilayer networks with 2,3-pyrazinedicarboxylate and oxalate.

Science.gov (United States)

Soares-Santos, Paula C R; Cunha-Silva, Luís; Paz, Filipe A Almeida; Ferreira, Rute A S; Rocha, João; Carlos, Luís D; Nogueira, Helena I S

2010-04-05

The hydrothermal reaction between lanthanide nitrates and 2,3-pyrazinedicarboxylic acid led to a new series of two-dimensional (2D) lanthanide-organic frameworks: [Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) [where 2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate, and Ln(III) = Ce, Nd, Sm, Eu, Gd, Tb, or Er]. The structural details of these materials were determined by single-crystal X-ray diffraction (for Ce(3+) and Nd(3+)) that revealed the formation of a layered structure. Cationic monolayers of {(infinity)(2)[Ln(2,3-pzdc)(H(2)O)](+)} are interconnected via the ox(2-) ligand leading to the formation of neutral (infinity)(2)[Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)] bilayer networks; structural cohesion of the crystalline packing is reinforced by the presence of highly directional O-H...O hydrogen bonds between adjacent bilayers. Under the employed hydrothermal conditions 2,3-pyrazinedicarboxylic acid can be decomposed into ox(2-) and 2-pyrazinecarboxylate (2-pzc(-)), as unequivocally proved by the isolation of the discrete complex [Tb(2)(2-pzc)(4)(ox)(H(2)O)(6)].10H(2)O. Single-crystal X-ray diffraction of this latter complex revealed its co-crystallization with an unprecedented (H(2)O)(16) water cluster. Photoluminescence measurements were performed for the Nd(3+), Sm(3+), Eu(3+), and Tb(3+) compounds which show, under UV excitation at room temperature, the Ln(3+) characteristic intra-4f(N) emission peaks. The energy level of the triplet states of 2,3-pyrazinedicarboxylic acid (18939 cm(-1)) and oxalic acid (24570 cm(-1)) was determined from the 12 K emission spectrum of the Gd(3+) compound. The (5)D(0) and (5)D(4) lifetime values (0.333 +/- 0.006 and 0.577 +/- 0.017 ms) and the absolute emission quantum yields (0.13 +/- 0.01 and 0.05 +/- 0.01) were determined for the Eu(3+) and Tb(3+) compounds, respectively. For the Eu(3+) compound the energy transfer efficiency arising from the ligands' excited states was estimated (0.93 +/- 0.01).

Rare earth chalcogels NaLnSnS{sub 4} (Ln = Y, Gd, Tb) for selective adsorption of volatile hydrocarbons and gases

Energy Technology Data Exchange (ETDEWEB)

Edhaim, Fatimah; Rothenberger, Alexander [Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

2017-08-16

The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS{sub 4}, NaGdSnS{sub 4}, and NaTbSnS{sub 4} is reported. Rare earth metal ions like Y{sup 3+}, Gd{sup 3+}, and Tb{sup 3+} react with the chalcogenide clusters [SnS{sub 4}]{sup 4-} in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m{sup 2}.g{sup -1} (NaYSnS{sub 4}), 479 m{sup 2}.g{sup -1} (NaGdSnS{sub 4}), and 354 m{sup 2}.g{sup -1} (NaTbSnS{sub 4}). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2-50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO{sub 2} over CH{sub 4} or H{sub 2}. The notable adsorption capacity for toluene (NaYSnS{sub 4}: 1108 mg.g{sup -1}; NaGdSnS{sub 4}: 921 mg.g{sup -1}; and NaTbSnS4: 645 mg.g{sup -1}) and high selectivity for gases (CO{sub 2}/H{sub 2}: 172 and CO{sub 2}/CH{sub 4}: 50 for NaYSnS{sub 4}, CO{sub 2}/H{sub 2}: 155 and CO{sub 2}/CH{sub 4}: 37 for NaGdSnS{sub 4}, and CO{sub 2}/H{sub 2}: 75 and CO{sub 2}/CH{sub 4}: 28 for NaTbSnS{sub 4}) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation of extraction resin for radio lanthanides separation; Preparacion de resina de extraccion para separacion de radiolantanidos

Energy Technology Data Exchange (ETDEWEB)

Cruz B, C.C. de la; Monroy G, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: delacruzbc@hotmail.com

2008-07-01

The present work presents the methodology that was developed for the preparation of one extractant resin with the aim of HDEHP, to separate radio lanthanides with serial atomic numbers. In this case it is exemplified with the separation of the following elements: Gadolinium-161 and the Terbium-161; this last radioisotope it is a beta emitting ({beta}{sup -}) that has a great potential to be used in therapy, also in nuclear medicine and in oncology, this is due to the high penetration power of their {beta}{sup -} particles that can kill to the cancerous cells and to inhibit the growth of the same ones. To be able to separate them it is necessary to appeal to extremely selective separation techniques, since the chemical properties of these elements are very similar. The chromatography is one of the more used analytical tools, this is due to its great sensibility and the selectivity in the compounds separation, in particular the use of the extractive chromatography has shown the feasibility of carrying out this type of separations for this type of elements. The resin with base of HDEHP was absorbed in an inert support under diverse preparation conditions. The extractant properties of the resin, in relation to the elements Gd and Tb (distribution coefficients), its were determined by means of the dynamic method, using as eluent solutions of nitric acid. The Gd-159 was prepared by irradiation of Gd-168 with thermal neutrons and the Tb-161 it is the result of the radioactive decay of the Gd-161 that is produced in turn with the irradiation with neutrons of Gd-160. The coefficients of distribution of Gd and Tb, using the prepared resin under diverse conditions are presented. (Author)

Spectroscopic study of magnetic phase transitions and magnetic structures in rare earth ferroborates RFe3(BO3)4 (R = Y, Er, Tb, Gd)

International Nuclear Information System (INIS)

Popova, M.N.; Chukalina, E.P.; Stanislavchuk, T.N.; Bezmaternykh, L.N.

2006-01-01

One investigated into the absorption spectra of RFe 3 (BO 3 ) 4 , R=Y, Er, Tb, Gd rare earth borate single crystals containing erbium (1%) introduced to serve as a probe. On the basis of the temperature dependences of Er 3+ ion spectral line splittings one determined the values of the magnetic ordering temperatures of Er, Tb and Gd ferroborates and the temperatures of the spin reoriented first order phase transition in GdFe 3 (BO 3 ) 4 :Er 3+ (1%). On the basis of comparison of the splitting values of Er 3+ ion ground state in RFe 3 (BO 3 ) 4 (R=Y, Er, Tb) and in GdFe 3 (BO 3 )4 compounds the magnetic structure of which is known one makes a concussion about the orientation of iron magnetic moments in the magneto-ordered state: a lightly planar structure is observed for YFe 3 (BO 3 ) 4 and ErFe 3 (BO 3 ) 4 and a lightly axial one - for TbFe 3 (BO 3 ) 4 . One discusses the role of R 3+ ion single ion anisotropy when determining the magnetic structure type in RFe 3 (BO 3 ) 4 [ru

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Science.gov (United States)

Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

2018-01-01

Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analogue substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analogue demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behaviour. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Synthesis and magneto-structural studies on a new family of carbonato bridged 3d-4f complexes featuring a [CoLn(CO3)] (Ln = La, Gd, Tb, Dy and Ho) core: slow magnetic relaxation displayed by the cobalt(ii)-dysprosium(iii) analogue.

Science.gov (United States)

Majee, Mithun Chandra; Towsif Abtab, Sk Md; Mondal, Dhrubajyoti; Maity, Manoranjan; Weselski, Marek; Witwicki, Maciej; Bieńko, Alina; Antkowiak, Michał; Kamieniarz, Grzegorz; Chaudhury, Muktimoy

2018-03-06

A new family of [3 + 3] hexanuclear 3d-4f complexes [(μ 3 -CO 3 ){Co II Ln III L(μ 3 -OH)(OH 2 )} 3 ]-(ClO 4 )·mC 2 H 5 OH·nH 2 O (1-5) [Ln = La (1), Gd (2), Tb (3), Dy (4), and Ho (5)] have been prepared in moderate to high yields (62-78%) following a self-assembly reaction between the ligand 6,6',6''-(nitrilotris(methylene))tris-(2-methoxy-4-methylphenol) (H 3 L), Co(OAc) 2 ·4H 2 O and the lanthanide ion precursors in the mandatory presence of tetrabutylammonium hydroxide. During the reaction, atmospheric carbon dioxide is fixed in the product molecule as a bridging carbonato ligand which connects all the three lanthanide centers of this molecular assembly through a rare η 2 :η 2 :η 2 -μ 3 mode of bridging as revealed from X-ray crystallography. The metal centers in all these compounds, except the Gd III analogue (2), are coupled in antiferromagnetic manner while the nature of coupling in the CoGd complex is ferromagnetic. DFT calculations revealed that this ferromagnetic interaction occurs most likely by the Co II -Gd III superexchange, mediated via the bridging oxygen atoms. Only the Co II -Dy III compound (4) displayed a slow relaxation of the magnetization at a very low temperature as established by AC susceptibility measurements. The data provides an estimation of the activation energy U/k B = 9.2 K and the relaxation time constant τ 0 = 1.0 × 10 -7 s.

High-speed magnetization reversal near the compensation temperature of amorphous GdTbFe

International Nuclear Information System (INIS)

Aeschlimann, M.; Vaterlaus, A.; Lutz, M.; Stampanoni, M.; Meier, F.; Siegmann, H.C.; Klahn, S.; Hansen, P.

1991-01-01

Using spin-polarized photoemission with a pulsed laser as light source, it is shown that the time for a thermally induced magnetization reversal depends critically on the temperature of the sample. For amorphous GdTbFe the time is shorter (longer) than the duration of the 16 ns laser pulses if the initial temperature is below (above) the compensation temperature

Morphotropic phase boundary and magnetoelastic behaviour in ferromagnetic Tb{sub 1−x}Gd{sub x}Fe{sub 2} system

Energy Technology Data Exchange (ETDEWEB)

Adil, Murtaza; Yang, Sen, E-mail: yang.sen@mail.xjtu.edu.cn; Mi, Meng; Zhou, Chao, E-mail: zhouch1982@gmail.com; Wang, Jieqiong; Zhang, Rui; Liao, Xiaoqi; Wang, Yu; Ren, Xiaobing; Song, Xiaoping, E-mail: xpsong@mail.xjtu.edu.cn [School of Sciences, Frontier Institute of Science and Technology, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ren, Yang [X-Ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2015-03-30

Morphotropic phase boundary (MPB), separating two ferroic phases of different crystal symmetries, has been studied extensively for its extraordinary enhancement of piezoelectricity in ferroelectrics. Based on the same mechanism, we have designed a magnetic MPB in the pseudobinary ferromagnetic system of Tb{sub 1−x}Gd{sub x}Fe{sub 2} and the corresponding crystal structure, magnetic properties, and magnetostriction are explored. With the synchrotron x-ray diffractometry, the structure symmetry of TbFe{sub 2}-rich compositions is detected to be rhombohedral (R) and that of GdFe{sub 2}-rich compositions is tetragonal (T) below T{sub c}. With the change of concentration, the value of magnetostriction of the samples changes monotonously, while the MPB composition Tb{sub 0.1}Gd{sub 0.9}Fe{sub 2}, which corresponds to the coexistence of R and T phases, exhibits the maximum magnetization among all available compositions and superposition of magnetostriction behaviour of R and T phases. Our result of MPB phenomena in ferromagnets may provide an effective route to design functional magnetic materials with exotic properties.

Luminescent lanthanide coordination polymers

Energy Technology Data Exchange (ETDEWEB)

Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

1999-12-13

One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

Synthesis, structures, and luminescent properties of lanthanide complexes with triphenylphospine oxide

Energy Technology Data Exchange (ETDEWEB)

Ma, Yan; Xu, Shan; Wang, Xin; Li, Yue-Xue; Jin, Qiong-Hua [Department of Chemistry, Capital Normal University, Beijing (China); Liu, Min [The College of Materials Science and Engineering, Beijing University of Technology (China); Xin, Xiu-Lan [School of Food and Chemical Engineering, Beijing Technology and Business University (China)

2017-07-03

Seven lanthanide complexes [Ln(OPPh{sub 3}){sub 3}(NO{sub 3}){sub 3}] (1-3) (OPPh{sub 3} = triphenylphosphine oxide, Ln = Nd, Sm, Gd), [Dy(OPPh{sub 3}){sub 4}(NO{sub 3}){sub 2}](NO{sub 3}) (4), [Ln(OPPh{sub 3}){sub 3}(NO{sub 3}){sub 3}]{sub 2} (5-7) (Ln = Pr, Eu, Gd) were synthesized by the reactions of different lanthanide salts and OPPh{sub 3} ligand in the air. These complexes were characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR and fluorescence spectra. Structure analysis shows that complexes 1-4 are mononuclear complexes formed by OPPh{sub 3} ligands and nitrates. The asymmetric units of complexes 5-7 consist of two crystallographic-separate molecules. Complex 1 is self-assembled to construct a 2D layer-structure of (4,4) net topology by hydrogen bond interactions. The other complexes show a 1D chain-like structure that was assembled by OPPh{sub 3} ligands and nitrate ions through C-H..O interactions. Solid emission spectra of compounds 4 and 6 are assigned to the characteristic fluorescence of Tb{sup 3+} (λ{sub em} = 480, 574 nm) and Eu{sup 3+} (λ{sub em} = 552, 593, 619, 668 nm). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Family of defect-dicubane Ni4Ln2 (Ln = Gd, Tb, Dy, Ho) and Ni4Y2 complexes: rare Tb(III) and Ho(III) examples showing SMM behavior.

Science.gov (United States)

Zhao, Lang; Wu, Jianfeng; Ke, Hongshan; Tang, Jinkui

2014-04-07

Reactions of Ln(III) perchlorate (Ln = Gd, Tb, Dy, and Ho), NiCl2·6H2O, and a polydentate Schiff base resulted in the assembly of novel isostructural hexanuclear Ni4Ln2 complexes [Ln = Gd (1), Tb (2), Dy (3), Ho (4)] with an unprecedented 3d-4f metal topology consisting of two defect-dicubane units. The corresponding Ni4Y2 (5) complex containing diamagnetic Y(III) atoms was also isolated to assist the magnetic studies. Interestingly, complexes 2 and 3 exhibit SMM characteristics and 4 shows slow relaxation of the magnetization. The absence of frequency-dependent in-phase and out-of-phase signals for the Ni-Y species suggests that the Ln ions' contribution to the slow relaxation must be effectual as previously observed in other Ni-Dy samples. However, the observation of χ″ signals with zero dc field for the Ni-Tb and Ni-Ho derivatives is notable. Indeed, this is the first time that such a behavior is observed in the Ni-Tb and Ni-Ho complexes.

Magnetic properties of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yao, Jinlei [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

2015-12-15

Magnetic properties and magnetocaloric effect of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds have been investigated. Magnetic measurements of RNi{sub 3}TSi display the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Graphical abstract: Magnetic measurements of RNi{sub 3}TSi show the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of 'RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi'. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Highlights: • CaCu{sub 5}-type RNi{sub 3}TSi show ferromagnetic ordering (R=Gd, Tb, T=Mn–Co, Cu). • Curie point increases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • MCE decreases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. • The coercive field of TbNi{sub 3}MnSi and TbNi{sub 3}FeSi reach 13 kOe and 16 kOe at 5 K.

'Gigantic' increase of AFMR frequencies induced by nonmagnetic impurity ions in orthoferrites RFe1-xAlxO3 (R=Gd,Tb)

International Nuclear Information System (INIS)

Mukhin, A.A.; Parsegov, I.Yu.

1996-01-01

We observed a 'gigantic' increase (up to three times) of the AFMR frequencies ν 1,2 with decreasing temperature in GdFe 0.9 Al 0.1 O 3 and TbFe 0.925 Al 0.075 O 3 in contrast to pure GdFeO 3 and TbFeO 3 . The effects observed are explained by the appearance of an additional exchange field H mv ∼20 -36 kOe on rare-earth ions due to decompensation of the surrounding antiferromagnetically ordered Fe ions near nonmagnetic impurity ions. (orig.)

Folic acid-conjugated GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2} Nanoprobe for folate receptor-targeted optical and magnetic resonance bi-modal imaging

Energy Technology Data Exchange (ETDEWEB)

Xu, Xianzhu [Jiangxi Normal University, College of Life Science, Jiangxi Provincial Key Laboratory of Protection and Utilization of Subtropical Plant Resources of Jiangxi Province (China); Zhang, Xiaoying; Wu, Yanli, E-mail: Wanny118@126.com [Jiangxi Science and Technology Normal University, Jiangxi Key Laboratory of Organic Chemistry (China)

2016-11-15

Both fluorescent and magnetic nanoprobes have great potential applications for diagnostics and therapy. In the present work, a folic acid-conjugated and silica-modified GdPO{sub 4}:Tb{sup 3+} (GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA) dual nanoprobe was strategically designed and synthesized for the targeted dual-modality optical and magnetic resonance (MR) imaging via a facile aqueous method. Their structural, optical, and magnetic properties were determined using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible spectra (UV-Vis), photoluminescence (PL), and superconducting quantum interference device (SQUID). These results indicated that GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA were uniform monodisperse core-shell structured nanorods (NRs) with an average length of ~200 nm and an average width of ~25 nm. The paramagnetic property of the synthesized GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA NRs was confirmed with its linear hysteresis plot (M-H). In addition, the NRs displayed an obvious T{sub 1}-weighted effect and thus it could potentially serve as a T{sub 1}-positive contrast agent. The NRs emitted green lights due to the {sup 5}D{sub 4} → {sup 7}F{sub 5} transition of the Tb{sup 3+}. The in vitro assays with NCI-H460 lung cancer cells and human embryonic kidney cell line 293T cells indicated that the GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA nanoprobe could specifically bind the cells bearing folate receptors (FR). The MTT assay of the NRs revealed that its cytotoxicity was very low. Further in vivo MRI experiments distinctively depict enhanced anatomical features in a xenograft tumor. These results suggest that the GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA NPs have excellent imaging and cell-targeting abilities for the folate receptor-targeted dual-modality optical and MR imaging and can be potentially used as the nanoprobe for bioimaging.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

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Florian Mayer

2018-01-01

Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Synthesis, density functional theory calculations and luminescence of lanthanide complexes with 2,6-bis[(3-methoxybenzylidene)hydrazinocarbonyl] pyridine Schiff base ligand.

Science.gov (United States)

Taha, Ziyad A; Ababneh, Taher S; Hijazi, Ahmed K; Abu-Salem, Qutaiba; Ajlouni, Abdulaziz M; Ebwany, Shroq

2018-02-01

A pyridine-diacylhydrazone Schiff base ligand, L = 2,6-bis[(3-methoxy benzylidene)hydrazinocarbonyl]pyridine was prepared and characterized by single crystal X-ray diffraction. Lanthanide complexes, Ln-L, {[LnL(NO 3 ) 2 ]NO 3 .xH 2 O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Er)} were prepared and characterized by elemental analysis, molar conductance, thermal analysis (TGA/DTGA), mass spectrometry (MS), Fourier transform infra-red (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. Ln-L complexes are isostructural with four binding sites provided by two nitro groups along with four coordination sites for L. Density functional theory (DFT) calculations on L and its cationic [LnL(NO 3 ) 2 ] + complexes were carried out at the B3LYP/6-31G(d) level of theory. The FT-IR vibrational wavenumbers were computed and compared with the experimentally values. The luminescence investigations of L and Ln-L indicated that Tb-L and Eu-L complexes showed the characteristic luminescence of Tb(III) and Eu(III) ions. Ln-L complexes show higher antioxidant activity than the parent L ligand. Copyright © 2017 John Wiley & Sons, Ltd.

Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

International Nuclear Information System (INIS)

Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E.; Chan, Benny C.; Lill, Daniel T. de

2015-01-01

Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C 6 H 2 O 5 )(C 6 H 3 O 5 )(H 2 O)] n (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted

Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

Energy Technology Data Exchange (ETDEWEB)

Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E. [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States); Chan, Benny C. [Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628 (United States); Lill, Daniel T. de, E-mail: ddelill@fau.edu [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States)

2015-05-15

Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C{sub 6}H{sub 2}O{sub 5})(C{sub 6}H{sub 3}O{sub 5})(H{sub 2}O)]{sub n} (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted.

Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS

International Nuclear Information System (INIS)

Bentlin, Fabrina R.S.; Santos, Clarissa M.M. dos; Flores, Érico M.M.; Pozebon, Dirce

2012-01-01

Highlights: ► Ultrasound was investigated and applied for red wine samples preparation. ► Aliquots of 50 μL of sample were nebulized and transported to plasma. ► FI and pneumatic nebulization/aerosol desolvation were used. ► LODs of the ICP-MS method for lanthanides determination were at ng L −1 level. ► Lanthanides concentration allowed red wines classification. - Abstract: This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L −1 , respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

Lanthanide-activated Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

Energy Technology Data Exchange (ETDEWEB)

Chen, Daqin, E-mail: dqchen@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, CAS, Fuzhou 350002 (China); Wan, Zhongyi; Zhou, Yang [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Chen, Yan, E-mail: chenyan@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Yu, Hua; Lu, Hongwei; Ji, Zhenguo [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Huang, Ping, E-mail: phuang@fjirsm.ac.cn [Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, CAS, Fuzhou 350002 (China)

2015-03-15

Highlights: • Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na{sub 5}Gd{sub 9}F{sub 32} lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na{sub 5}Gd{sub 9}F{sub 32} lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb{sup 3+}/Er{sup 3+} ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties.

Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln==Sm, Eu, Gd) and [Ln(dien)2(1κ2-AsS4)] (Ln==Tb, Dy, Ho)

International Nuclear Information System (INIS)

Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

2013-01-01

Solvothermal reactions of Ln 2 O 3 , As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien) 2 (1κ 2 -AsS 4 )] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln 2 O 3 oxides were converted to [Ln(dien) 2 ] 3+ complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS 4 unit. In 1−3, the AsS 4 units interconnect the [Ln(dien) 2 ] 3+ cations via Ln−S bonds as tridentate μ-1κ,2κ 2 -AsS 4 bridging ligands, resulting in the neutral coordination polymers [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n (Ln1). In 4−6, the AsS 4 units coordinate with the Ln 3+ ion of [Ln(dien) 2 ] 3+ as 1κ 2 -AsS 4 chelating ligands to form neutral coordination compounds [Ln(dien) 2 (1κ 2 -AsS 4 )] (Ln2). The Ln 3+ ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln 3+ ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien) 2 (μ-1κ,2κ 2 -AsS 4 )] n and [Ln(dien) 2 (1κ 2 -AsS 4 )] were prepared by solvothermal methods and the soft Lewis basic AsS 4 3– ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS 4 ligand coordinate Ln 3+ ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors with optical band gaps in the range 2.18−3.21 eV

Direct two-photon excitation of Sm3+, Eu3+, Tb3+, Tb.DOTA-, and Tb.propargylDO3A in solution

Science.gov (United States)

Sørensen, Thomas Just; Blackburn, Octavia A.; Tropiano, Manuel; Faulkner, Stephen

2012-07-01

We have observed direct two-photon excitation of samarium, europium and terbium ions in solution upon near IR excitation using a tuneable pulsed light source, and have also studied two-photon processes in a pair of related terbium complexes, namely [Tb.DOTA]- and Tb.propargylDO3A. Direct two-photon excitation of lanthanides is observed in simple systems in the absence of sensitizing chromophores. Where even simple chromophores such as a triple bond are present in the complex, then single and two-photon excitation of chromophore excited states competes with direct two-photon excitation of the ions and is the dominant pathway for sensitizing formation of the lanthanide excited state.

Luminescence and energy transfer of Tb3+-doped BaO-Gd2O3-Al2O3-B2O3-SiO2 glasses.

Science.gov (United States)

Zuo, Chenggang; Huang, Jinze; Liu, Shaoyou; Xiao, Anguo; Shen, Youming; Zhang, Xiangyang; Zhou, Zhihua; Zhu, Ligang

2017-12-05

Transparent Tb 3+ -doped BaO-Gd 2 O 3 -Al 2 O 3 -B 2 O 3 -SiO 2 glasses with the greater than 4g/cm 3 were prepared by high temperature melting method and its luminescent properties have been investigated by measured UV-vis transmission, excitation, emission and luminescence decay spectra. The transmission spectrum shows there are three weak absorption bands locate at about 312, 378 and 484nm in the glasses and it has good transmittance in the visible spectrum region. Intense green emission can be observed under UV excitation. The effective energy transfer from Gd 3+ ion to Tb 3+ ion could occur and sensitize the luminescence of Tb 3+ ion. The green emission intensity of Tb 3+ ion could change with the increasing SiO 2 /B 2 O 3 ratio in the borosilicate glass matrix. With the increasing concentration of Tb 3+ ion, 5 D 4 → 7 F J transitions could be enhanced through the cross relaxation between the two nearby Tb 3+ ions. Luminescence decay time of 2.12ms from 546nm emission is obtained. The results indicate that Tb 3+ -doped BaO-Gd 2 O 3 -Al 2 O 3 -B 2 O 3 -SiO 2 glasses would be potential scintillating material for applications in X-ray imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating x-ray detectors for radiographic applications: A comparison of nSCdS:Ag with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb screens

CERN Document Server

Kandarakis, I; Panayiotakis, G S; Nomicos, C D

1997-01-01

ZnSCdS:Ag was evaluated as a radiographic image receptor and was compared with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb phosphors often used in radiography. The valuation of a radiographic receptor was modelled as a three-step process: i) determination of light output intensity as related to the input radiation dose, (ii) determination of visible light characteristics with respect to radiographic optical detectors, and (iii) determination of image information transfer efficiency. The light intensity emitted per unit of x-ray exposure rate was measured and theoretically calculated for laboratory prepared screens with coating thicknesses from 20 to 220 mg cm sup - sup 2 and tube voltages rom 50 to 250 kVp. ZnSCdS:Ag light intensity was higher than that of d sub 2 O sub 2 S:Tb or Y sub 2 O sub 2 S:Tb for tube voltages less than 70 and 80 kVp respectively. ZnSCdS:Ag displayed the highest x-ray to light conversion efficiency (0.207) and had optical properties close to those of Gd sub 2 O sub 2 S:Tb nd Y sub ...

Thermochemical properties of lanthanoid-iron-perovskite at high temperatures. [La, Nd, Sm, Eu, Gd, Tb, Dy

Energy Technology Data Exchange (ETDEWEB)

Katsura, T; Kitayama, K; Sugihara, T [Tokyo Inst. of Tech. (Japan). Faculty of Science; Kimizuka, N

1975-06-01

The standard Gibbs energy of formation of C/sup -/FeO/sub 3/(C/sup -/=La, Nd, Sm, Eu, Gd, Tb, and Dy) from metallic iron, C/sub 2//sup -/O/sub 3/, and oxygen has been determined at temperatures from 1473 to 1673 K. Based on the free-energy data, the heat of reaction and the entropy change resulting from the reaction have been calculated. The values of the heat of reaction of LaFeO/sub 3/, NdFeO/sub 3/, SmFeO/sub 3/, EuFeO/sub 3/, and GdFeO/sub 3/ (the first group) were identical, - 107 kcal/mol, at the present temperature interval. However, the values of the heat of reaction of TbFeO/sub 3/ and DyFeO/sub 3/ (the second group) decreased with an increase in the temperature. The entropy change of each reaction in the first group was constant, independent of the temperature, and each value decreased in the sequence from LaFeO/sub 3/ to GdFeO/sub 3/. The entropy change of the second group decreased with an increase in the temperature. The change of the standard Gibbs energy was intimately related to the ionic radii of C/sup -/-ions, and the relationship between the Gibbs energy and the tolerance factor has been clarified.

N-(sulfoethyl) iminodiacetic acid-based lanthanide coordination polymers: Synthesis, magnetism and quantum Monte Carlo studies

Energy Technology Data Exchange (ETDEWEB)

Zhuang Guilin, E-mail: glzhuang@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Chen Wulin [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Zheng Jun [Center of Modern Experimental Technology, Anhui University, Hefei 230039 (China); Yu Huiyou [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Wang Jianguo, E-mail: jgw@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China)

2012-08-15

A series of lanthanide coordination polymers have been obtained through the hydrothermal reaction of N-(sulfoethyl) iminodiacetic acid (H{sub 3}SIDA) and Ln(NO{sub 3}){sub 3} (Ln=La, 1; Pr, 2; Nd, 3; Gd, 4). Crystal structure analysis exhibits that lanthanide ions affect the coordination number, bond length and dimension of compounds 1-4, which reveal that their structure diversity can be attributed to the effect of lanthanide contraction. Furthermore, the combination of magnetic measure with quantum Monte Carlo(QMC) studies exhibits that the coupling parameters between two adjacent Gd{sup 3+} ions for anti-anti and syn-anti carboxylate bridges are -1.0 Multiplication-Sign 10{sup -3} and -5.0 Multiplication-Sign 10{sup -3} cm{sup -1}, respectively, which reveals weak antiferromagnetic interaction in 4. - Graphical abstract: Four lanthanide coordination polymers with N-(sulfoethyl) iminodiacetic acid were obtained under hydrothermal condition and reveal the weak antiferromagnetic coupling between two Gd{sup 3+} ions by Quantum Monte Carlo studies. Highlights: Black-Right-Pointing-Pointer Four lanthanide coordination polymers of H{sub 3}SIDA ligand were obtained. Black-Right-Pointing-Pointer Lanthanide ions play an important role in their structural diversity. Black-Right-Pointing-Pointer Magnetic measure exhibits that compound 4 features antiferromagnetic property. Black-Right-Pointing-Pointer Quantum Monte Carlo studies reveal the coupling parameters of two Gd{sup 3+} ions.

The effect of core and lanthanide ion dopants in sodium fluoride-based nanocrystals on phagocytic activity of human blood leukocytes

Science.gov (United States)

Sojka, Bartlomiej; Liskova, Aurelia; Kuricova, Miroslava; Banski, Mateusz; Misiewicz, Jan; Dusinska, Maria; Horvathova, Mira; Ilavska, Silvia; Szabova, Michaela; Rollerova, Eva; Podhorodecki, Artur; Tulinska, Jana

2017-02-01

Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples.

Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Bentlin, Fabrina R.S. [Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501.970 Porto Alegre, RS (Brazil); Santos, Clarissa M.M. dos; Flores, Erico M.M. [Departamento de Quimica Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Pozebon, Dirce, E-mail: dircepoz@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501.970 Porto Alegre, RS (Brazil)

2012-01-13

Highlights: Black-Right-Pointing-Pointer Ultrasound was investigated and applied for red wine samples preparation. Black-Right-Pointing-Pointer Aliquots of 50 {mu}L of sample were nebulized and transported to plasma. Black-Right-Pointing-Pointer FI and pneumatic nebulization/aerosol desolvation were used. Black-Right-Pointing-Pointer LODs of the ICP-MS method for lanthanides determination were at ng L{sup -1} level. Black-Right-Pointing-Pointer Lanthanides concentration allowed red wines classification. - Abstract: This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 {mu}L of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L{sup -1}, respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

Extraction of lanthanide(III) nitrates from water-salt solutions with n.-octanol

International Nuclear Information System (INIS)

Keskinov, V.A.; Kudrova, A.V.; Valueva, O.V.; Pyartman, A.K.

2004-01-01

Extraction of lanthanide(III) nitrates (Ln=La-Nd, Sm-Gd) from aqueous-salt solutions at 298.15 K was studied using solution of n.-octanol, its concentration 6.31 mol/l. It was ascertained that at Ln(NO 3 ) 3 concentration in aqueous phase below 0.6 mol/l, there is actually no extraction. At higher concentrations of nitrates in aqueous phase the content of lanthanides(III) in organic phase increases in the series La-Gd. Isotherms of extraction were ascertained, its phase equilibria being described mathematically. It is shown that extraction of lanthanide(III) nitrates with n.-octanol should be realized from concentrated aqueous solutions [ru

Síntesis hidrotermal de monocristales LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er

Directory of Open Access Journals (Sweden)

Señarís Rodríguez, M. A.

2008-08-01

Full Text Available Ten single crystals of the series LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er were synthesized by hydrothermal synthesis in a single step and without subsequent thermal treatments from aqueous solutions of metals salts at 240 ºC. The obtained single crystals have a size of various micrometers and their morphology changes throughout the serie: they are polygonal in the case of the compounds with Ln= Pr, Nd, Sm, Eu and Gd and needle-like in the case of the compounds with Ln= Y, Tb, Dy, Ho and Er. After the analysis of the obtained products employing different conditions of synthesis we attributed the different morphology to a greater growth rate along the c axis when the smaller ions (Y, Tb, Dy, Ho y Er are involved, due to their better adaptation to the compound’s crystal structure.Se han conseguido preparar monocristales de 10 óxidos mixtos de la serie LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er mediante síntesis hidrotermal optimizada, en un único paso y sin tratamientos térmicos posteriores partiendo de las correspondientes sales metálicas en disolución acuosa a 240 ºC. Los monocristales obtenidos son relativamente grandes, de varias micras y su morfología varía a lo largo de la serie: es poligonal en el caso de los compuestos de los lantánidos del inicio de la serie (Ln= Pr, Nd, Sm, Eu y Gd y acicular en el caso de los compuestos de Y y de los lantánidos del final de la serie (Ln= Tb, Dy, Ho y Er. Tras el análisis de los productos obtenidos empleando distintas condiciones de síntesis atribuimos la diferente morfología a una mayor velocidad de crecimiento cristalino a lo largo del eje c cuando intervienen los iones más pequeños (Y, Tb, Dy, Ho y Er debido a la mejor adaptación de éstos últimos a la estructura cristalina del compuesto.

Three phenoxo-bridged dinuclear lanthanide complexes. Syntheses, crystal structures, and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhi-Chao; Dai, Rui-Peng; Yang, En-Cui [College of Chemistry, Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, Tianjin Normal University (China); Dong, Hui-Ming; Zhao, Xiao-Jun [College of Chemistry, Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry, Tianjin Normal University (China); Department of Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin (China)

2018-03-15

Three dinuclear lanthanide complexes [Ln{sub 2}(H{sub 2}L){sub 2}(NO{sub 3}){sub 4}] [Ln = Dy (1), Tb (2), and Gd (3)] [H{sub 3}L = 2-hydroxyimino-N'-[(2-hydroxy-3-methoxyphenyl)methylidene]- propanohydrazone] were solvothermally synthesized by varying differently anisotropic rare earth ions. Single-crystal structural analyses demonstrate that all the three complexes are crystallographically isostructural with two centrosymmetric Ln{sup III} ions aggregated by a pair of monodeprotonated H{sub 2}L{sup -} anions. Weak intramolecular antiferromagnetic interactions with different strength were mediated by a pair of phenoxo bridges due to superexchange and/or single-ion anisotropy. Additionally, the Dy{sup III}-based entity shows the strongest anisotropy exhibits field-induced single-molecule magnetic behavior with two thermally activated relaxation processes. In contrast, 3 with isotropic Gd{sup III} ion has a significant cryogenic magnetocaloric effect with the maximum entropy change of 25.7 J.kg{sup -1}.K{sup -1} at 2.0 K and 70.0 kOe. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Photoluminescence properties of lanthanide-organic frameworks (LnOFs) with thiophene-2,5-dicarboxylate and acetate

Energy Technology Data Exchange (ETDEWEB)

Han, Jing; Wei, Qing; Xie, Gang; Chen, Sanping [Key Lab. of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest Univ., Xi' an, Shaanxi (China); Zhang, Sheng [Key Lab. of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest Univ., Xi' an, Shaanxi (China); College of Chemistry and Chemical Engineering, Baoji Univ. of Arts and Science, Baoji, Shaanxi (China)

2017-07-17

S-heterocyclic dicarboxylic acid, thiophene-2,5-dicarboxylic acid (H{sub 2}TDC), was employed to construct a series of lanthanide-organic frameworks (LnOFs) with coligand acetate, formulated as [Ln(TDC)(OAc)(H{sub 2}O)]{sub n} [Ln = Eu (1), Tb (2), Gd (3), Dy (4), Sm (5)] under hydrothermal conditions. Structure analysis reveals that 1-5 have dinuclear 3D metal organic frameworks (MOFs), in which TDC{sup 2-} and OAc{sup -} display (κ{sup 1}-κ{sup 1})-(κ{sup 1}-κ{sup 1})-μ{sub 4} and (κ{sup 2}-κ{sup 1})-μ{sub 2} coordination fashions, respectively. The dehydrated products of all compounds show high thermal stability above 410 C. As for 1, 2, 4, and 5, the photoluminescence analyses exhibit characteristic luminescence emission bands of the corresponding lanthanide ions in the visible region. In particular, compound 2 displays bright green luminescence in the solid state with {sup 5}D{sub 4} lifetime of 0.510 ms and relative high overall quantum yield of 16 %, based on an ideal energy gap between the lowest triplet state energy level of H{sub 2}TDC ligand and the {sup 5}D{sub 4} state energy level of Tb{sup 3+}. The energy transfer mechanisms in compounds 1 and 2 were also discussed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis and Structural Investigation of New Bio-Relevant Complexes of Lanthanides with 5-Hydroxyflavone: DNA Binding and Protein Interaction Studies

Directory of Open Access Journals (Sweden)

Alexandra-Cristina Munteanu

2016-12-01

Full Text Available In the present work, we attempted to develop new metal coordination complexes of the natural flavonoid 5-hydroxyflavone with Sm(III, Eu(III, Gd(III, Tb(III. The resultant hydroxo complexes have been characterized by a variety of spectroscopic techniques, including fluorescence, FT-IR, UV-Vis, EPR and mass spectral studies. The general chemical formula of the complexes is [Ln(C15H9O33(OH2(H2Ox]·nH2O, where Ln is the lanthanide cation and x = 0 for Sm(III, x = 1 for Eu(III, Gd(III, Tb(III and n = 0 for Sm(III, Gd(III, Tb(III, n = 1 for Eu(III, respectively. The proposed structures of the complexes were optimized by DFT calculations. Theoretical calculations and experimental determinations sustain the proposed structures of the hydroxo complexes, with two molecules of 5-hydroxyflavone acting as monoanionic bidentate chelate ligands. The interaction of the complexes with calf thymus DNA has been explored by fluorescence titration and UV-Vis absorption binding studies, and revealed that the synthesized complexes interact with DNA with binding constants (Kb ~ 104. Human serum albumin (HSA and transferrin (Tf binding studies have also been performed by fluorescence titration techniques (fluorescence quenching studies, synchronous fluorescence spectra. The apparent association constants (Ka and thermodynamic parameters have been calculated from the fluorescence quenching experiment at 299 K, 308 K, and 318 K. The quenching curves indicate that the complexes bind to HSA with smaller affinity than the ligand, but to Tf with higher binding affinities than the ligand.

Selective removal of lanthanides from natural waters, acidic streams and dialysate

Energy Technology Data Exchange (ETDEWEB)

Yantasee, Wassana, E-mail: wassana.yantasee@pnl.gov [Pacific Northwest National Laboratory (PNNL), P.O. Box 999, Richland, WA 99352 (United States); Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya [Pacific Northwest National Laboratory (PNNL), P.O. Box 999, Richland, WA 99352 (United States); Xu Jide; Raymond, Kenneth N. [Chemistry Department, University of California, Berkeley, CA 94720 (United States); LBNL, Berkeley, CA 94720 (United States)

2009-09-15

The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS{sup TM}), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 {mu}g/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning.

Selective removal of lanthanides from natural waters, acidic streams and dialysate

International Nuclear Information System (INIS)

Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu Jide; Raymond, Kenneth N.

2009-01-01

The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS TM ), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 μg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning.

A study of luminescence from Eu{sup 3+}, Ce{sup 3+}, Tb{sup 3+} and Ce{sup 3+}/Tb{sup 3+} in new potassium gadolinium phosphate K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}

Energy Technology Data Exchange (ETDEWEB)

Meng, Fangui; Zhang, Hongzhi [School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China); Chen, Cuili; Kim, Sun Il [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Zhang, Xinmin, E-mail: xmzhuga@163.com [School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004 (China)

2016-06-25

New potassium gadolinium phosphate [K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}] doped with Eu{sup 3+}, Ce{sup 3+}, Tb{sup 3+} and co-doped with Ce{sup 3+} and Tb{sup 3+} phosphors were prepared by high temperature solid state synthesis. Phase purity of the powders was checked by X-ray powder diffraction. Luminescence and excitation spectra of samples were reported. In particular, the interaction mechanism between Eu{sup 3+} ions was investigated in terms of the Inokuti–Hirayama model; it was found that the interactions between Eu{sup 3+} can be assigned to dipole–dipole interaction. K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}:Eu{sup 3+} could act as a candidate for solid state lighting due to its strong absorption band in the near-UV region (350–400 nm). The energy transfer from Ce{sup 3+} to Tb{sup 3+} was confirmed and the mechanism was studied using Dexter's theory; it is concluded that electric dipole–dipole interaction predominates in the energy transfer process from Ce{sup 3+} to Tb{sup 3+} in the K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6} host. The energy transfer efficiency and critical distance were also investigated. - Highlights: • Optical properties of K{sub 3}Gd{sub 5}(PO{sub 4}){sub 6}:RE{sup 3+} are investigated for the first time. • The interaction mechanism between Eu{sup 3+} ions is attributed to dipole–dipole type. • K{sub 3}Eu{sub 5}(PO{sub 4}){sub 6} is a candidate phosphor for application to solid state lighting. • There exists an efficient energy transfer from Ce{sup 3+} to Tb{sup 3+} (η is up to 95%). • The mechanism of energy transfer process is electric dipole–dipole interaction.

Tune color of single-phase LiGd(MoO4)2-X(WO4)X: Sm3+, Tb3+ via adjusting the proportion of matrix and energy transfer to create white-light phosphor

Science.gov (United States)

Wu, Hongyue; Yang, Junfeng; Wang, Xiaoxue; Gan, Shucai; Li, Linlin

2018-03-01

A series of LiGd(MO4)2: Sm3+, Tb3+ (M = Mo, W) phosphors was prepared by a conventional solid state reaction method. Powder X-Ray diffraction (XRD) analysis reveals that the compounds are of the same structure type. Their luminescent properties have been studied. The optimal doping concentrations are 8% for Sm3+ and 18% for Tb3+ in the LiGd(MoO4)2 host. Sm3+ and Tb3+ have different sensitivity to the Mo/W ratio. For LiGd(MoO4)2-X(WO4)X: Sm3+ (X = 0, 0.4, 0.8, 1.2, 1.6, 2.0), the strongest emission intensity is 1.766 times than that of the weakest, while 171 times for LiGd(MoO4)2-X(WO4)X: Tb3+. The experimental results show that Mo/W ratio strong influences on the properties of LiGd(MoO4)2-X(WO4)X: Tb3+. With the increasing of WO42- groups concentration, the shape of characteristic excitation peaks of Tb3+ is almost the same and the excitation intensity gradually increase. Moreover, the energy transfer from Tb3+ to Sm3+ has been realized in the co-doped phosphors. The experimental analysis and theoretical calculations reveal that the quadrupole-quadrupole interaction is the dominant mechanism for the Tb3+→Sm3+ energy transfer. Therefore, luminous intensity can be adjusted by different sensitivities to matrix composition and energy transfer from Tb3+→Sm3+. By this tuning color method, white-light-emitting phosphor has been prepared. The excitation wavelength is 378 nm, and this indicates that the white-light-emitting phosphor could be pumped by near-UV light.

Theoretical investigations on magnetic entropy change in amorphous and crystalline systems: Applications to RAg (R=Tb, Dy, Ho) and GdCuAl

Energy Technology Data Exchange (ETDEWEB)

Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Alho, B.P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 RJ (Brazil); Ribeiro, P.O.; Alvarenga, T.S.T.; Lopes, P.H.O.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

2014-11-15

We report theoretical investigations on the magnetic entropy changes in amorphous systems through two different assumptions. In the first assumption, the HPZ-anisotropic model is considered to deal with the random direction of magnetic moments, where the amorphous RAg (R=Tb, Dy and Ho) were used as prototypes systems. In the second assumption, the amorphisation is parameterized through the exchange interaction distribution and GdCuAl, in amorphous and crystalline structures, were considered as prototypes systems. Comparisons between the magnetic entropy changes under amorphisation and under the usual magnetic field variation were performed. The model reveals the dependence of refrigerant capacity on the amorphisation parameter, and an optimum amorphisation parameter was calculated. - Highlights: • Theoretical investigation on RAg (R=Tb, Dy and Ho) and GdCuAl amorphous alloys. • Magnetic entropy changes in GdCuAl in both amorphous and crystalline structures. • The refrigerant capacity was compared in both amorphous and crystalline phases.

Lanthanides(3)/ actinides (3) separation by nano-filtration-complexation in aqueous medium

International Nuclear Information System (INIS)

Chitry, F.; Pellet-Rostaing, S.; Gozzi, C.; Lemaire, M.; Guy, A.; Foos, J.

2000-01-01

Lanthanides(III)/actinides(III) separation is a major research subject in matter of treatment of high activity liquid effluents. Liquid-liquid extraction actually gives the best results for this separation. In order to demonstrate that nano-filtration (NF) is a valuable alternative to liquid-liquid extraction, we tried to separate different lanthanides(III) with a nano-filtration process combined with a selective complexation step. At first DTPA (diethylene-triamine-pentaacetic acid) combined with a Sepa MG-17 (Osmonics) gave a 95% retention of Gd 3+ and a 50% retention of La 3+ . Then new hydrosoluble and more selective ligands derived from DTPA were synthesized. One of them combined with a Sepa MG-17 membrane allowed a 87% retention of Gd 3+ and a 5% retention of La 3+ . The same nano-filtration-complexation system was experimented with an equimolar aqueous solution of Gd 3+ , Pr 3+ and La 3+ . Other experiments in the field of actinides(III)/lanthanides(III) separation were also performed. (authors)

Gas-phase reactivity of lanthanide cations with fluorocarbons: C-F versus C-H and C-C bond activation

International Nuclear Information System (INIS)

Cornehl, H.H.; Hornung, G.; Schwarz, H.

1996-01-01

The gas-phase reactivity of the fluorinated hydrocarbons CF 4 , CHF 3 , CH 3 F, C 2 F 6 , 1,1-C 2 H 4 F 2 , and C 6 F 6 with the lanthanide cations Ce + , Pr + , Sm + , Ho + , Tm + , and Yb + and the reactivity of C 6 H 5 F with all lanthanide cations Ln + (Ln = La-Lu, with the exception of Pm + ) have been examined by Fourier-transform ion cyclotron resonance mass spectrometry. The perfluorinated compounds tetrafluoromethane and hexafluoroethane as well as trifluoromethane do not react with any lanthanide cation. Selective activation of the strong C-F bonds in fluoromethane, 1,1-difluoroethane, hexafluorobenzene, and fluorobenzene appears as a general reaction scheme along the 4f row. Experimental evidence is given for a 'harpoon'-like mechanism for the F atom abstraction process which operates via an initial electron transfer from the lanthanide cation to the fluorinated substrate in the encounter complex Ln + RF. The most reactive lanthanides La + , Ce + , Gd + , and Tb + and also the formal closed-shell species Lu + exhibit additional C-H and C-C bond activation pathways in the reaction with fluorobenzene, namely dehydrohalogenation as well as loss of a neutral acetylene molecule. In the case of Tm + and Yb + the formation of neutral LnF 3 is observed in a multistep process via C-C coupling and charge transfer. 17 refs., 2 figs., 2 tabs

Synthesis, structural characterization, luminescent properties and theoretical study of three novel lanthanide metal-organic frameworks of Ho(III), Gd(III) and Eu(III) with 2,5-thiophenedicarboxylate anion

Energy Technology Data Exchange (ETDEWEB)

Marques, Lippy F. [Instituto de Química, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20550-013 (Brazil); Correa, Charlane C. [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil); Ribeiro, Sidney J.L.; Santos, Molíria V. dos [Institute of Chemistry, São Paulo State University − UNESP, CP 355 Araraquara-SP 14801-970 Brazil (Brazil); Dutra, José Diogo L.; Freire, Ricardo O. [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Machado, Flávia C., E-mail: flavia.machado@ufjf.edu.br [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil)

2015-07-15

In this paper, the synthesis of three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structure of (1) reveals that each lanthanide ion is seven-coordinated by oxygen atoms in an overall distorted capped trigonal – prismatic geometry. The 2,5-tdc{sup 2−} ligands connect four Ln(III) centers, adopting (κ{sup 1}–κ{sup 1})–(κ{sup 1}–κ{sup 1})–μ{sub 4} coordination mode, generating an 8-connected uninodal 3D network. In addition, theoretical studies for Eu(III) complex were performed using the Sparkle model for lanthanide complexes. - Graphical abstract: Three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), were synthesized and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. - Highlights: • Three new LnMOFs were synthesized and fully characterized. • Ho{sup 3+}, Gd{sup 3+} and Eu{sup 3+} complexes photoluminescence properties were investigated. • Theoretical approaches for Eu{sup 3+} complex luminescence has been performed. • An energy level diagram is used to establish the ligand-to-metal energy transfer. • These metal−organic frameworks can act as light conversion molecular devices.

Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds

Science.gov (United States)

Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

2018-02-01

The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.

Determination of stability constants of lanthanide nitrate complex formation using a solvent extraction technique

International Nuclear Information System (INIS)

Andersson, S.; Ekberg, C.; Liljenzin, J.O.; Nilsson, M.; Skarnemark, G.; Eberhardt, K.

2006-01-01

For lanthanides and actinides, nitrate complex formation is an important factor with respect to the reprocessing of nuclear fuels and in studies that treat partitioning and transmutation/conditioning. Different techniques, including microcalorimetry, various kinds of spectroscopy, ion-exchange and solvent extraction, can be used to determine stability constants of nitrate complex formation. However, it is uncommon that all lanthanides are studied at the same time, using the same experimental conditions and technique. The strengths of the complexes are different for lanthanides and actinides, a feature that may assist in the separation of the two groups. This paper deals with nitrate complex formation of lanthanides using a solvent extraction technique. Trace amounts of radioactive isotopes of lanthanides were produced at the TRIGA Mainz research reactor and at the Institutt for Energiteknikk in Kjeller, Norway (JEEP II reactor). The extraction of lanthanide ions into an organic phase consisting of 2, 6-bis-(benzoxazolyl)-4-dodecyloxylpyridine, 2-bromodecanoic acid and tert-butyl benzene as a function of nitrate ion concentration in the aqueous phase was studied in order to estimate the stability constants of nitrate complex formation. When the nitrate ion concentration is increased in the aqueous phase, the nitrate complex formation starts to compete with the extraction of metal ions. Thus the stability constants of nitrate complex formation can be estimated by measuring the decrease in extraction and successive fitting of an appropriate model. Extraction curves for La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Dy, Ho and Er were obtained and stability constants for their nitrate complex formation were estimated. Tb, Tm, Yb and Lu were also investigated, but no stability constants could be determined. The distribution ratios for the metal ions at low nitrate ion concentration were obtained at the same time, showing the effect of lanthanide contraction resulting in decreasing

Predictions of thermomagnetic properties of Laves phase compounds: TbAl2, GdAl2 and SmAl2 performed with ATOMIC MATTERS MFA computation system

Science.gov (United States)

Michalski, Rafał; Zygadło, Jakub

2018-04-01

Recent calculations of properties of TbAl2 GdAl2 and SmAl2 single crystals, performed with our new computation system called ATOMIC MATTERS MFA are presented. We applied localized electron approach to describe the thermal evolution of Fine Electronic Structure of Tb3+, Gd3+ and Sm3+ ions over a wide temperature range and estimate Magnetocaloric Effect (MCE). Thermomagnetic properties of TbAl2, GdAl2 and SmAl2 were calculated based on the fine electronic structure of the 4f8, 4f7 and 4f5 electronic configuration of the Tb3+ and Gd3+ and Sm3+ ions, respectively. Our calculations yielded: magnetic moment value and direction; single-crystalline magnetization curves in zero field and in external magnetic field applied in various directions m(T,Bext); the 4f-electronic components of specific heat c4f(T,Bext); and temperature dependence of the magnetic entropy and isothermal entropy change with external magnetic field - ΔS(T,Bext). The cubic universal CEF parameters values used for all CEF calculations was taken from literature and recalculated for universal cubic parameters set for the RAl2 series: A4 = +7.164 Ka04 and A6 = -1.038 Ka06. Magnetic properties were found to be anisotropic due to cubic Laves phase C15 crystal structure symmetry. These studies reveal the importance of multipolar charge interactions when describing thermomagnetic properties of real 4f electronic systems and the effectiveness of an applied self-consistent molecular field in calculations for magnetic phase transition simulation.

Color tunable emission in Ce3+ and Tb3+ co-doped Ba2Ln(BO3)2Cl (Ln=Gd and Y) phosphors for white light-emitting diodes.

Science.gov (United States)

Zhang, Niumiao; Guo, Chongfeng; Jing, Heng; Jeong, Jung Hyun

2013-12-01

Ce(3+) and Tb(3+) co-doped Ba2Ln(BO3)2Cl (Ln=Y and Gd) green emitting phosphors were prepared by solid state reaction in reductive atmosphere. The emission and excitation spectra as well as luminescence decays were investigated, showing the occurrence of efficient energy transfer from Ce(3+) to Tb(3+) in this system. The phosphors exhibit both a blue emission from Ce(3+) and a green emission from Tb(3+) under near ultraviolet light excitation with 325-375 nm wavelength. Emission colors of phosphors could be tuned from deep blue through cyan to green by adjusting the Tb(3+) concentrations. The energy transfer efficiency and emission intensity of Ba2Y(BO3)2Cl:Ce(3+), Tb(3+) precede those of Ba2Gd(BO3)2Cl:Ce(3+), Tb(3+), and the sample Ba2Y(BO3)2Cl:0.03Ce(3+), 0.10Tb(3+) is the best candidate for n-UV LEDs. Copyright © 2013 Elsevier B.V. All rights reserved.

Construction of Polynuclear Lanthanide (Ln = Dy(III), Tb(III), and Nd(III)) Cage Complexes Using Pyridine-Pyrazole-Based Ligands: Versatile Molecular Topologies and SMM Behavior.

Science.gov (United States)

Bala, Sukhen; Sen Bishwas, Mousumi; Pramanik, Bhaskar; Khanra, Sumit; Fromm, Katharina M; Poddar, Pankaj; Mondal, Raju

2015-09-08

Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl-pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl-pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement.

Calmodulin-lanthanide ion exchange kinetics

International Nuclear Information System (INIS)

Buccigross, J.; O'Donnell, C.; Nelson, D.

1985-01-01

A flow dialysis apparatus suitable for the study of high affinity metal binding proteins has been utilized to study calmodulin-metal exchange kinetics. Calmodulin labeled with Eu-155 and Gd-153 was dialyzed against buffer containing various competing metal ions. The rate of metal exchange was monitored by a gamma-ray scintillation detector. The kinetics of exchange are first order, and the rates fall into two categories: Ca (II) and CD (II) in one, and the lanthanides Eu (III), Gd (III), and La (III) in the other

Hyperfine interaction studies of the perovskite oxides of the type RCrO3 (R = Gd, Tb e Dy)

International Nuclear Information System (INIS)

Silva, Renilson Adriano da

2009-01-01

ABO 3 perovskite oxides have ideal cubic structure, however, some distortions in this type of structure may induce changes from cubic to orthorhombic or rhombroedric symmetry. The larger atoms A are located at the center of a cube, the B atoms are on 8 vertices and oxygen atoms occupy 12 positions in the middle of each side of the cube. Distortions in this structure may lead to new magnetic and electrical properties, with great scientific and technological interest. In this work RCrO 3 (R = Gd, Tb, Dγ) compounds (also known as orthocromites) were studied. The samples were produced by means of sol-gel chemical procedure and analyzed by X-Ray Diffraction. The results showed a single phase with Pbnm space group. The perturbed gamma-gamma angular correlation (PAC) measurements were carried out using 181 Hf( 181 Ta) and 111 In( 111 Cd) nuclear probes, which substitute 'A' and 'B' positions respectively. The probe nuclei were introduced in the samples during the chemical procedures for preparation. One of the objectives of this work's was to study the hyperfine magnetic field and its variation as a function of temperature, crystallographic structure as well as the antiferromagnetic transition temperature (T N ). The PAC Measurements were carried out in the temperature range of 20 to 300 K for R = Gd, Tb and 20 to 800 K in the case of R = Dγ from. Electric field gradient was also measured as a function of temperature. It was possible to observe the expected transition as well as the alignment of Cr spins, as found in literature. The Neel temperatures (TN) for investigated samples are ∼170 K, ∼164 K and ∼148 K for GdCrO 3 , TbCrO 3 and DyCrO 3 respectively. (author)

Study on the fabrication and photoluminescence characteristics of LiBO2 glass scintillators with the lanthanides activators

International Nuclear Information System (INIS)

Sin, S. W.; Hwang, J. H.; Choi, S. H.; Sumarokov, S. Yu.

2002-01-01

LiBO 2 glass scintillators were fabricated, and lanthanides(except Pm) oxides or chlorides were used as an activator. For the fabrication of LiBO 2 glasses, optimum heating conditions were obtained, and the photoluminescence of the glasses was measured by the monochromator. For the best transparency of the glass samples, optimum heating temperature and time are 1000 .deg. C and 40 min, respectively. The result of photoluminescence analysis shows that Pr, Nd, Gd, Ho, Er, Tm, Yb, and Lu are not good as activator. Because emission spectrum of samples with them was equal to that of sample without activator. In the case of samples with Europium, the peak of emission spectrum of Eu(III) is 810 nm. And Samples with Ce(III) are 760 nm, and Tb(III) are about 535 nm. Samples with Ce(III) and Tb(III) have the best PL intensity with added sugar in Ar reduction atmosphere, and sample with Eu(III) has the best intensity without a reducing process

Transport properties in amorphous U/sub x/-T1/sub -//sub x/ films (T = Fe, Ni, Gd, Tb, and Yb) (invited)

International Nuclear Information System (INIS)

Freitas, P.P.; Plaskett, T.S.; Moreira, J.M.; Amaral, V.S.

1988-01-01

We describe the competing magnetic, localization, and phonon effects on the transport properties of amorphous magnetic U/sub x/T/sub 1-//sub x/ films, with T = Fe, Ni, Gd, Tb, and Yb. Amorphous U/sub x/Fe/sub 1-//sub x/ films change from collinear to random ferromagnetism as x increases, and the temperature dependence of the resistivity denotes the competing effects of spin-flip and non-spin-flip exchange scattering processes. The resistivity has a minimum at T/sub f/ rising sharply below this temperature. The sign of the magnetic resistivity and the magnetoresistance indicates >0, while the anisotropic magnetoresistance indicates a local exchange gap. Amorphous U/sub x/Gd/sub 1-//sub x/ and a-U/sub x/Tb/sub 1-//sub x/ are, respectively, spin glasses and random anisotropy dominated systems. The resistivity increases smoothly through T/sub f/ and has a slight upturn at low temperatures that we associate with weak localization. The magnetoresistance is negative in both systems and the anisotropic magnetoresistance is null, although the applied field induces anisotropic behavior in the Tb containing films (asperomagnets). All samples show quadratic and positive field dependence of magnetoresistance well inside the paramagnetic regime, and a linear regime below T/sub f/. At low temperatures and in the a-U/sub x/Gd/sub 1-//sub x/ films, negative (H)/sup 1/2/ and H 2 regimes occur and are associated with weak localization processes dominated by the inelastic mean free path

A role of copper(II) ions in the enhancement of visible and near-infrared lanthanide(III) luminescence

International Nuclear Information System (INIS)

Eliseeva, Svetlana V.; Golovach, Iurii P.; Liasotskyi, Valerii S.; Antonovich, Valery P.; Petoud, Stéphane; Meshkova, Svetlana B.

2016-01-01

Most of the existing optical methods for Cu II detection rely on a “turn-off” approach using visible lanthanide(III) luminescence. In this work we present an innovative molecular systems where the podands bis(2-hydrazinocarbonylphenyl) ethers of ethylene glycol (L1) and diethylene glycol (L2) have been designed, synthesised and tested with an ultimate goal to create a "turn-on" lanthanide(III)-based molecular probe for the specific detection of Cu II ions based on both visible (Tb III , Eu III ) and near-infrared (Nd III , Yb III ) emission. Quantum yields of the characteristic Ln III emission signals increases by at least two-orders of magnitude upon addition of Cu II into water/acetonitrile (9/1) solutions of LnL (L=L1, L2) complexes. A detailed investigation of ligand-centred photophysical properties of water/acetonitrile (9/1) solutions of CuL, GdL and GdCuL complexes revealed that the presence of Cu II ions does not significantly affect the energy positions of the singlet (32,260 cm −1 ) and triplet (25,640–25,970 cm −1 ) states, but partially or fully eliminates the singlet state quenching through an electron transfer mechanism. This effect increases the probability of intersystem crossing leading to enhanced triplet-to-singlet emission ratio and to longer triplet state lifetimes. The redox activity of hydrazine moieties and their ability to reduce Cu II to Cu I has been indicated by a qualitative assay with neocuproine. Finally, the probe demonstrates a good selectivity towards Cu II over other transition metal ions: the addition of divalent Zn II , Cd II , Pd II , Ni II , Co II or trivalent Fe III , Ga III , In III ion salts into solutions of TbL either does not affect emission intensity or increases it to a maximum of 2–3 times, while, under similar experimental conditions, the presence of Cu II results in a 20- to 30-times lanthanide luminescence enhancement. This new strategy results in a versatile and selective optical platform for the

Fabrication and characterization of Gd2O2SO4:Tb3+ phosphors by sol-gel method

Science.gov (United States)

Aritman, I.; Yildirim, S.; Kisa, A.; Guleryuz, L. F.; Yurddaskal, M.; Dikici, T.; Celik, E.

2017-02-01

The objective of the innovative approaches of the scintillation materials to be used in the digital portal imaging systems in the radiotherapy applications is to research the GOS material production that has been activated with the rare earth elements (RE), to produce the scintillation detectors that have a rapid imaging process with a lesser radiation and higher image quality from these materials and to apply the radiographic imaging systems. The GOS: Tb3+ showed high emission peak and high x-ray absorption properties which have been determined for application to mammography and dental radiography. In this study, Gd2O2SO4:Tb3+ phosphors were fabricated by the sol-gel method that is a unique technique and not previously applied. Besides, the structural characterization of GOS: Tb3+ has been investigated. The strongest emission peak located at 549 nm under 312 nm UV light excitation was appeared on the GOS: Tb3+ phosphor particles. The characterization processing optimized by using FTIR, DTA-TG, XRD, XPS, SEM and the luminescence spectroscopy.

Synthesis and photoluminescence characteristics of (Y,Gd)BO3:RE (RE = Eu(3+), Ce(3+), Dy(3+) and Tb(3+)) phosphors for blue chip and near-UV white LEDs.

Science.gov (United States)

Rangari, V V; Singh, V; Dhoble, S J

2016-03-01

A series of Eu(3+)-, Ce(3+)-, Dy(3+)- and Tb(3+)-doped (Y,Gd)BO3 phosphors was synthesized by a solid-state diffusion method. X-Ray diffraction confirmed their hexagonal structure and the scanning electron microscopy results showed crystalline particles. The excitation spectra revealed that (Y,Gd)BO3 phosphors doped with Eu(3+), Ce(3+), Dy(3+) and Tb(3+) are effectively excited with near UV-light of 395 nm/blue light, 364, 351 and 314 nm, respectively. Photoluminescence spectra of Eu(3+)-, Ce(3+)- and Tb(3+)/Dy(3+)-doped phosphor showed intense emission of reddish orange, blue and white light, respectively. The phosphor Y0.60Gd0.38BO3:Ce0.02 showed CIE 1931 color coordinates of (0.158, 0.031) and better color purity compared with commercially available blue BAM:Eu(2+) phosphor. The phosphor (Y,Gd)BO3 doped with Eu(3+), Dy(3+) and Tb(3+) showed CIE 1931 color coordinates of (0.667, 0.332), (0.251, 0.299) and (0.333, 0.391) respectively. Significant photoluminescence characteristics of the prepared phosphors indicate that they might serve as potential candidates for blue chip and near-UV white light-emitting diode applications. Copyright © 2015 John Wiley & Sons, Ltd.

Optical and magneto-optical properties of single crystals of RFe{sub 2} (R = Gd, Tb, Ho, and Lu) and GdCo{sub 2} intermetallic compounds

Energy Technology Data Exchange (ETDEWEB)

Lee, S.J.

1999-02-12

The author has studied the diagonal and off-diagonal optical conductivity of RFe{sub 2}(R = Gd, Tb, Ho, Lu) and GdCo{sub 2} single crystals grown by the flux method. Using spectroscopic ellipsometry the author has measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields between 0.5 to 1.6 T. The apparatus and calibration method are described in detail. Using magneto-optical data and optical constants he derives the experimental value of the off-diagonal conductivity components. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. He applied this TB-LMTO method to LuFe{sub 2}. The theoretical results obtained agree well with the experimental data. The oxidation effects on the diagonal part of the optical conductivity were considered using a three-phase model. The oxidation effects on the magneto-optical parameters were also considered by treating the oxide layer as a nonmagnetic thin transparent layer. These corrections change not only the magnitude but also the shape of the optical conductivity and the magneto-optical parameters.

Pulse EPR-enabled interpretation of scarce pseudocontact shifts induced by lanthanide binding tags

Energy Technology Data Exchange (ETDEWEB)

Abdelkader, Elwy H.; Yao, Xuejun [Australian National University, Research School of Chemistry (Australia); Feintuch, Akiva [Weizmann Institute of Science, Department of Chemical Physics (Israel); Adams, Luke A.; Aurelio, Luigi; Graham, Bim [Monash University, Monash Institute of Pharmaceutical Sciences (Australia); Goldfarb, Daniella [Weizmann Institute of Science, Department of Chemical Physics (Israel); Otting, Gottfried, E-mail: gottfried.otting@anu.edu.au [Australian National University, Research School of Chemistry (Australia)

2016-01-15

Pseudocontact shifts (PCS) induced by tags loaded with paramagnetic lanthanide ions provide powerful long-range structure information, provided the location of the metal ion relative to the target protein is known. Usually, the metal position is determined by fitting the magnetic susceptibility anisotropy (Δχ) tensor to the 3D structure of the protein in an 8-parameter fit, which requires a large set of PCSs to be reliable. In an alternative approach, we used multiple Gd{sup 3+}-Gd{sup 3+} distances measured by double electron–electron resonance (DEER) experiments to define the metal position, allowing Δχ-tensor determinations from more robust 5-parameter fits that can be performed with a relatively sparse set of PCSs. Using this approach with the 32 kDa E. coli aspartate/glutamate binding protein (DEBP), we demonstrate a structural transition between substrate-bound and substrate-free DEBP, supported by PCSs generated by C3-Tm{sup 3+} and C3-Tb{sup 3+} tags attached to a genetically encoded p-azidophenylalanine residue. The significance of small PCSs was magnified by considering the difference between the chemical shifts measured with Tb{sup 3+} and Tm{sup 3+} rather than involving a diamagnetic reference. The integrative sparse data approach developed in this work makes poorly soluble proteins of limited stability amenable to structural studies in solution, without having to rely on cysteine mutations for tag attachment.

A comparative study of the structure and luminescence of mono- and dinuclear crown-ether lanthanide complexes

Energy Technology Data Exchange (ETDEWEB)

Souza, Keyla M.N. de [Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, S/N – Dois Irmãos, 52171-900 Recife, Pernambuco (Brazil); Batista, Hélcio J., E-mail: helciojb@gmail.com [Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, S/N – Dois Irmãos, 52171-900 Recife, Pernambuco (Brazil); Belian, Mônica F. [Departamento de Química, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, S/N – Dois Irmãos, 52171-900 Recife, Pernambuco (Brazil); Silva, Wagner E. [Unidade Acadêmica do Cabo de Santo Agostinho, Universidade Federal Rural de Pernambuco, 54510-000 Cabo de Santo Agostinho, Pernambuco (Brazil); Silva, Juliana A.B. da [Centro Acadêmico do Agreste, Universidade Federal de Pernambuco, 55002-970 Caruaru, Pernambuco (Brazil)

2016-02-15

Using as precursor the mononuclear lanthanide (Ln) macrocyclic complex, based on the 15-crown-5 ether (C) ligand and coordinated water (W) molecules, [LnCW{sub 4}]{sup 3+}, four novel analogous complexes for each of the three Ln(III) ions (Ln=Eu, Tb and Gd) were synthesized through systematic substitution of water molecules by the antenna-type ligands: 2,2′-dipyridyl (D), 1,10-phenanthroline (P) and 2,2′;6',2′′-terpyridine (T). The corresponding formulae of the complexes, obtained in a trichloride salt form, were the following: [LnCW{sub 4}]{sup 3+}, [LnCP{sub 2}]{sup 3+}, [LnCDW]{sup 3+}, [LnCDP]{sup 3+}, and [LnCT]{sup 3+}. The compounds were characterized by elemental analysis, UV and infrared spectroscopy and investigated through luminescence spectroscopy. For the Eu(III) and Tb(III) complex series, the most luminescent ones were [EuCDP]{sup 3+} and [TbCT]{sup 3+}, respectively. Motivated by this fact, two dinuclear analogous Eu(III) and Tb(III) complexes, based on the two-site coordinating macrocyclic ligand lariat-silacrown ether (S), as well as analogous Gd(III) complexes, were obtained as hexachloride salts with the following formulae: [Eu{sub 2}SD{sub 2}P{sub 2}]{sup 6+}, [Gd{sub 2}SD{sub 2}P{sub 2}]{sup 6+}, [Tb{sub 2}ST{sub 2}]{sup 6+} and [Gd{sub 2}ST{sub 2}]{sup 6+}. Also, [Eu{sub 2}SW{sub 8}]{sup 6+}, [Tb{sub 2}SW{sub 8}]{sup 6+} and [Gd{sub 2}SW{sub 8}]{sup 6+} complexes were prepared and used as reference non-antenna type dinuclear compounds. Comparing the luminescence between the antenna mononuclear complexes with the analogous dinuclear ones, for Eu(III) and Tb(III) ions, almost no change was observed. On the other hand, in the particular case of Eu(III), comparing the mono- and dinuclear non-antenna reference complexes [EuCW{sub 4}]{sup 3+} and [Eu{sub 2}SW{sub 8}]{sup 6+}, a surprisingly much higher luminescence intensity was observed for the dinuclear complex (~ one order of magnitude). The proposed cause for this behavior is the

Paramagnetic Nanocrystals: Remarkable Lanthanide-Doped Nanoparticles with Varied Shape, Size, and Composition.

Science.gov (United States)

Holmberg, Rebecca J; Aharen, Tomoko; Murugesu, Muralee

2012-12-20

Magnetic nanoparticles have been developed in recent years with applications in unique and crucial areas such as biomedicine, data storage, environmental remediation, catalysis, and so forth. NaYF4 nanoparticles were synthesized and isolated with lanthanide dopant percentages, confirmed by ICP-OES measurements, of Er, Yb, Tb, Gd, and Dy that were in agreement with the targeted ratios. SEM images showed a distinct variation in particle size and shape with dopant type and percentage. HRTEM and XRD studies confirmed the particles to be crystalline, possessing both α and β phases. Magnetic measurements determined that all of the nanoparticles were paramagnetic and did not exhibit a blocking temperature from 2 to 300 K. The multifunctional properties of these nanoparticles make them suitable for many applications, such as multimodal imaging probes, up-conversion fluorescent markers, as well as MRI contrast agents.

Spectrophotometric Study of Ternary Complex Forming Systems of Some Lanthanide Metal Ions with Eriochrome Cyanine R in Presence of Cetylpyridinium Bromide for Microdetermination

Directory of Open Access Journals (Sweden)

A. S. Dhepe

2011-01-01

Full Text Available Study of coordination compounds of lanthanide elements has received a great attention due to growing applications in science and technology. Number of chromogenic reagents form water soluble colored complexes with lanthanides. Eriochrome cyanine R (ECR a member of triphenylmethane type of dye has been reported to form green colored complexes with lanthanides and has been used for microdetermination of these metal ions. Addition of cationic surfactant, Cetylpyridinium bromide (CPB, a cationic surfactant sensitizes the color reactions of Gd(III, Tb(III, Dy(III, Ho(III and Lu(III with ECR. Formation of water soluble, highly colored ternary complexes with a considerable bathochromic shift of about 50 nm in presence of surfactant has been observed. Optimum reaction conditions and other analytical parameters were also evaluated. Stoichiometric ratio 1:3:3 of Ln: ECR: CPB are responsible for the observed rise in molar absorptivity and sensitivity. Beer’s law was obeyed between 0.50 to 13.00 ppm. Effective photometric range and molar absorptivity of these ternary complexes have been calculated. Effect of some common interfering ions on determination of these lanthanide metal ions was studied. A simple, rapid and highly sensitive spectrophotometeric method has been proposed for the determination of metal ions understudy.

Enhancement of CdSiO3: Tb3+ green long-lasting phosphors by co-doping with Re3+ (Re3+=Gd3+, Y3+, La3+) ions

International Nuclear Information System (INIS)

Zeng, Wei; Wang, Yuhua; Han, Shaochun; Chen, Wenbo; Li, Gen

2014-01-01

CdSiO 3 : Tb 3+ , Re 3+ long-lasting phosphors were synthesized by the conventional high temperature solid-state method. A green-light phosphorescence phenomenon, which was associated with the 5 D 4 → 7 F J (J=6, 5, 4, 3) transitions of the Tb 3+ ion, was observed. Introduction of Re 3+ (Re 3+ =Gd 3+ , Y 3+ , La 3+ ) ions, which deepens the depth (E t ) or/and increases the density (n 0 ) of traps, greatly improved the afterglow properties of CdSiO 3 : Tb 3+ . Possible mechanism of CdSiO 3 : Tb 3+ , Re 3+ was discussed in this work. - Highlights: • CdSiO 3 : Tb 3+ , Re 3+ samples enrich the color of long-lasting afterglow phosphors in CdSiO 3 host. • Both the afterglow intensity and the lasting time are greatly enhanced for the co-doped samples, especially for Cd 0.96 SiO 3 : Tb 0.03 3+ , La 0.01 3+ . • Introduction of Re 3+ (Re 3+ =Gd 3+ , Y 3+ , La 3+ ) ions, which deepens the depth (E t ) or increase density(n 0 ) of traps, greatly improved the afterglow properties of CdSiO 3 : Tb 3+

Synthesis, crystal structure and luminescence properties of lanthanide coordination polymers with a new semirigid bridging thenylsalicylamide ligand

International Nuclear Information System (INIS)

Song, Xue-Qin; Wang, Li; Zhao, Meng-Meng; Wang, Xiao-Run; Peng, Yun-Qiao; Cheng, Guo-Quan

2013-01-01

Two new lanthanide coordination polymers based on a semirigid bridging thenylsalicylamide ligand ([Ln 2 L 3 (NO 3 ) 6 ]·(C 4 H 8 O 2 ) 2 ) ∞ were obtained and characterized by elemental analysis, X-ray diffraction, IR and TGA measurements. The two compounds are isostructure and possess one dimensional trapezoid ladder-like chain built up from the connection of isolated LnO 3 (NO 3 ) 3 polyhedra (distorted monocapped antisquare prism) through the ligand. The photoluminescence analysis suggest that there is an efficient ligand-to-Ln(III) energy transfer in Tb(III) complex and the ligand is an efficient “antenna” for Tb(III). From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarge the arsenal for developing excellent luminescent lanthanide coordination polymers. - Graphical abstract: We present herein one dimensional lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display interesting structures but also possess strong luminescence properties. Display Omitted - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit interesting structures. • The luminescent properties of Tb(III) complexes are discussed in detail

Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

Energy Technology Data Exchange (ETDEWEB)

Liu, Baoxia [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Huang, Yankai [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Xu; Hao, Yuanqiang [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Ding, Yujie [College of Biochemical Engineering, Anhui Polytechnic University, Wuhu 241000 (China); Wei, Wei; Wang, Qi [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Qu, Peng, E-mail: qupeng0212@163.com [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xu, Maotian, E-mail: xumaotian@sqnc.edu.cn [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

2016-03-17

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg{sup 2+} detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb{sup 3+} from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg{sup 2+} into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg{sup 2+}. As a kind of Hg{sup 2+} nanosensor, the probe exhibited excellent selectivity for Hg{sup 2+} and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg{sup 2+} in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg{sup 2+} was achieved based on time-resolved spectroscopy.

Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

International Nuclear Information System (INIS)

Liu, Baoxia; Huang, Yankai; Zhu, Xu; Hao, Yuanqiang; Ding, Yujie; Wei, Wei; Wang, Qi; Qu, Peng; Xu, Maotian

2016-01-01

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg"2"+ detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb"3"+ from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg"2"+ into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg"2"+. As a kind of Hg"2"+ nanosensor, the probe exhibited excellent selectivity for Hg"2"+ and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg"2"+ in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg"2"+ was achieved based on time-resolved spectroscopy.

Lanthanide complexes of macrocyclic polyoxovanadates by VO4 units: synthesis, characterization, and structure elucidation by X-ray crystallography and EXAFS spectroscopy.

Science.gov (United States)

Nishio, Masaki; Inami, Shinnosuke; Katayama, Misaki; Ozutsumi, Kazuhiko; Hayashi, Yoshihito

2012-01-16

Reactions of a tetravanadate anion, [V(4)O(12)](4-), with a series of lanthanide(III) salts yield three types of lanthanide complexes of macrocyclic polyoxovanadates: (Et(4)N)(6)[Ln(III)V(9)O(27)] [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6)], (Et(4)N)(5)[(H(2)O)Ho(III)(V(4)O(12))(2)] (7), and (Et(4)N)(7)[Ln(III)V(10)O(30)] [Ln = Er (8), Tm (9), Yb (10), Lu (11)]. Lanthanide complexes 1-11 are isolated and characterized by IR, elemental analysis, single-crystal X-ray diffraction, and extended X-ray absorption fine structure spectroscopy (EXAFS). Lanthanide complexes 1-6 are composed of a square-antiprism eight-coordinated Ln(III) center with a macrocyclic polyoxovanadate that is constructed from nine VO(4) tetrahedra through vertex sharing. The structure of 7 is composed of a seven-coordinated Ho(III) center, which exhibits a capped trigonal-prism coordination environment by the sandwiching of two cyclic tetravanadates with a capping H(2)O ligand. Lanthanide complexes 8-11 have a six-coordinated Ln(III) center with a 10-membered vanadate ligand. The structural trend to adopt a larger coordination number for a larger lanthanide ion among the three types of structures is accompanied by a change in the vanadate ring sizes. These lanthanide complexes are examined by EXAFS spectroscopies on lanthanide L(III) absorption edges, and the EXAFS oscillations of each of the samples in the solid state and in acetonitrile are identical. The Ln-O and Ln···V bond lengths obtained from fits of the EXAFS data are consistent with the data from the single-crystal X-ray studies, reflecting retention of the structures in acetonitrile.

Cloud point extraction: an alternative to traditional liquid-liquid extraction for lanthanides(III) separation.

Science.gov (United States)

Favre-Réguillon, Alain; Draye, Micheline; Lebuzit, Gérard; Thomas, Sylvie; Foos, Jacques; Cote, Gérard; Guy, Alain

2004-06-17

Cloud point extraction (CPE) was used to extract and separate lanthanum(III) and gadolinium(III) nitrate from an aqueous solution. The methodology used is based on the formation of lanthanide(III)-8-hydroxyquinoline (8-HQ) complexes soluble in a micellar phase of non-ionic surfactant. The lanthanide(III) complexes are then extracted into the surfactant-rich phase at a temperature above the cloud point temperature (CPT). The structure of the non-ionic surfactant, and the chelating agent-metal molar ratio are identified as factors determining the extraction efficiency and selectivity. In an aqueous solution containing equimolar concentrations of La(III) and Gd(III), extraction efficiency for Gd(III) can reach 96% with a Gd(III)/La(III) selectivity higher than 30 using Triton X-114. Under those conditions, a Gd(III) decontamination factor of 50 is obtained.

Coordination chemistry of several radius-sensitive complexones and applications to lanthanide-actinide separations

Energy Technology Data Exchange (ETDEWEB)

Potter, M.W.

1981-10-01

The relationships between the lanthanide complex formation equilibria and the lanthanide-actinide separation application of three radius sensitive ligands have been studied. The consecutive stepwise formation constants of the 1:1, 2:1, and 3:1 chelate species formed by the interaction of DHDMB and the tripositive lanthanides and yttrium were determined potentiometrically at 0.1 M ionic strength and 25/sup 0/C. Results indicate that three different coordination modes, one tridentate and two bidentate are in evidence. Tracer level /sup 241/Am - /sup 155/Eu cation-exchange experiments utilizing DHDMB eluents indicate that this dihydroxycarboxylate does not form a sufficiently strong americium complex to elute that actinide ahead of europium. The overall stability of the americium 3:1 complex appears intermediate between samarium and europium. Cation-exchange elutions of /sup 241/Am, /sup 155/Eu, and /sup 160/Tb mixtures with EEDTA solutions prove that the EEDTA ligand is capable of eluting americium ahead of all of the tripositive lanthanide cations. The minimum separation occurs with terbium, where the Am-Tb separation factor is 1.71. 1,5-diaminopentane-N,N,N',N'-tetraacetic acid (PMDTA) was synthesized using cation exchange. A mathematical method was developed for the formation constants of the protonated and unprotonated lanthanide-PMDTA complexes from potentiometry. Cation-exchange elutions of tracer quantities of Am, Eu, and Tb revealed that terbium is eluted ahead of both americium and europium.

Formation constants of lanthanide(III)- aminopolycarboxylate- ATP mixed ligand complexes and their systematics

International Nuclear Information System (INIS)

Verma, Sangeeta; Limaye, S.N.; Saxena, M.C.

1993-01-01

Formation constants (log Ksub(MAL)sup(MA), log Ksub(ML)sup(M) and log Ksub(ML)sup(ML) of mixed ligand lanthanide(III) complexes of the type [Ln(III).A.ATP[ 2 , where LN(III)=La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ or Dy 3+ ' A=NTA(nitrilotriacetate) or HEDTA (2-hydroxyethylethylenediamine triacetate) and ATP=adenosine 5'-triphosphate (L), and of the binary [Ln(III).ATP[ and [Ln(III).(ATP) 2 [ complexes have been determined by potentiometric pH titrations using the Irving-Rossotti approach at three temperatures 20, 30 and 40 degC and at a fixed ionic strength, I=0.2 mol dm -3 (NAclO 4 ). The solution stabilities (log Ksub(MAL)sup(MA) values) are influenced by the electrostatic effect involved in ternary complexation and increase with temperature. The enthalpy factor (ΔH) has been found to be small but unfavourable and the entropy factor (ΔS) large and favourable. The log Ksub(MAL)sup(MA) values lie in the order NTA>HEDTA with respect to A and La 3+ 3+ 3+ 3+ 3+ 3+ >Gd 3+ 3+ 3+ with respect to lanthanides. Tetrad effect is present in the formation constant values; its magnitude has been found to lie in the sequence f 7 >f 3 -f 4 ≅ f 10 -f 11 for the Ln(III) ions. Systematics in the formation constant values has been further studied by evaluating changes in the inter-electronic repulsion Racah parameters, extra stabilisation of specific 4f 9 -configurations and nephelauxetic ratio using experimental values of the formation constants. (author). 24 refs., 2 figs., 3 tabs

Novel open-framework architectures in lanthanide phosphonates

Science.gov (United States)

Groves, John A.; Stephens, Nicholas F.; Wright, Paul A.; Lightfoot, Philip

2006-03-01

Two novel three-dimensional lanthanide coordination polymers have been prepared hydrothermally with the phosphonic acid N,N-piperazine bis(methylenephosphonic acid), H 2O 3PCH 2N(C 2H 4) 2NCH 2PO 3H 2 ( LH 4). The structures of Gd 2( LH 2) 3ṡ3H 2O (I) and Nd 2( LH 2) 3ṡ9H 2O (II) have been characterised by single crystal X-ray techniques. One-dimensional 'lanthanide-phosphate' chains are a key feature in both structures, although there are major structural differences between the chains, with (I) displaying octahedral GdO 6 coordination and (II) showing eight-coordinate NdO 8 polyhedra. In each case, three-dimensional connectivity is completed by coordination of the phosphonate group resulting in open framework structures encapsulating loosely bound water molecules. Isostructural Y 3+ and Yb 3+ analogues of (I) have been prepared, suggesting that cation size is a key factor in controlling the differing reaction products. In the case of Y 2( LH 2) 3ṡ5H 2O, isostructural to (I), it is shown that the extra-framework water molecules may be removed reversibly without framework collapse. Structural relationships to other known lanthanide phosphonates are discussed.

Synthesis and magnetism of μ-oxamido-bridged Cu2IILnIII - type heterotrinuclear complexes (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er)

International Nuclear Information System (INIS)

Li, Y.T.; Yan, C.W.

2001-01-01

Eight new Cu 2 II Ln III - type (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er) heterotrinuclear complexes bridged by N,N'-bis (2-aminopropyl)oxamidocopper(II) [Cu(oxdn)], namely Cu 2 (oxdn)Ln(NO 3 ) 3 , have been synthesized and characterized by elemental analyses, molar conductivity measurements and spectroscopic (IR, UV, ESR) studies. Magnetic susceptibility measurements (4.2 ∼300 K) and studies of Cu 2 (oxdn)Gd(NO 3 ) 3 complex have revealed that the central gadolinium(III) and terminal copper(II) ions are ferromagnetically coupled with the exchange integral J (Cu-Gd) = +2.98 cm -1 , while an antiferromagnetic coupling is detected between the terminal copper(II) metal ions with the exchange integral J' (Cu-Gd) = -0.75 cm -1 , on the basis of the spin Hamiltonian operator [H -2J(S Cu1 -S Gd +S Cu2 +S Gd )-2J'(S Cu1 S Cu2 )]. (author)

Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln = Nd, Gd, Er) at high pressure.

Science.gov (United States)

Turner, Katlyn M; Tracy, Cameron L; Mao, Wendy L; Ewing, Rodney C

2017-11-09

Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln=Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare it to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant property that influences their compression response. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the bond in stannate pyrochlore is more covalent than the bonds in titanates, zirconate, and hafnates. In stannates, the pyrochlore cation and anion sublattices begin to disorder at 0.3 GPa. The extent of sublattice disorder vs. pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to a cotunnite-like structure (Pnma) at ~28 GPa; similar transitions have been observed in titanate, zirconate, and hafnate pyrochlore at varying pressures with cation radius ratio. The extent of the phase transition vs. pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multiscale defect-fluorite + weberite structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlore treated to similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B0, of stannates varies linearly and inversely with cation radius ratio. The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates, and suggest that the size of the Ln3+ cation is a primary determining factor of B0. Additionally, when normalized to rA/rB, the bulk moduli of stannates are comparable to those of zirconates and hafnates, which vary from titanates. Our results suggest that the cation radius ratio strongly influences the bulk moduli of stannates as well as

Preparation and studies of Eu3+ and Tb3+ co-doped Gd2O3 and Y2O3 sol-gel scintillating films

International Nuclear Information System (INIS)

Morales Ramirez, A. de J; Garcia Murillo, A.; Carrillo Romo, F. de J; Ramirez Salgado, J.; Le Luyer, C.; Chadeyron, G.; Boyer, D.; Moreno Palmerin, J.

2009-01-01

Eu 3+ (2.5 at.%) and Tb 3+ (0.005-0.01 at.%) co-doped gadolinium and yttrium oxide (Gd 2 O 3 and Y 2 O 3 ) powders and films have been prepared using the sol-gel process. High density and optical quality thin films were prepared with the dip-coating technique. Gadolinium (III) 2,4-pentadionate and yttrium (III) 2,4-pentadionate were used as precursors, and europium and terbium in their nitrate forms were used as doping agents. Chemical and structural analyses (infrared spectroscopy, X-ray diffraction and high-resolution transmission electron microscopy) were conducted on both sol-gel precursor powders and dip-coated films. The morphology of thin films heat-treated at 700 o C was studied by means of atomic force microscopy. It was shown that the highly dense and very smooth films had a root mean roughness (RMS) of 2 nm ± 0.2 (A = 0.0075 Tb 3+ ) and 24 nm ± 3.0 (B = 0.01 Tb 3+ ). After treatment at 700 o C, the crystallized films were in the cubic phase and presented a polycrystalline structure made up of randomly oriented crystallites with grain sizes varying from 20 to 60 nm. The X-ray induced emission spectra of Eu 3+ - and Tb 3+ -doped Gd 2 O 3 and Y 2 O 3 powders showed that Tb 3+ contents of 0.005, 0.0075 and 0.01 at.% affected their optical properties. Lower Tb 3+ concentrations (down to 0.005 at.%) in both systems enhanced the light yield.

Tb3+ and Eu3+ luminescence in imidazolium ionic liquids

International Nuclear Information System (INIS)

Hopkins, Todd; Goldey, Matt

2009-01-01

The luminescence properties of Tb 3+ and Eu 3+ dissolved in ionic liquids are studied. Solutes in this study include simple lanthanide compounds (e.g., EuBr 3 , TbCl 3 ) and lanthanide complexes (e.g., Eu(dpa) 3 3- where dpa = 2,6 pyridine dicarboxylate dianion) dissolved in a 1-butyl-3-methylimidazolium bromide(BMIBr)/water mixture. Emission, excitation, and time-resolved emission measurements are utilized to characterize the spectroscopic properties. It is well established in the literature that the solubility and spectroscopic properties of lanthanides in ionic liquids are highly dependent upon environmental factors including purity, and water content [K. Binnemans, Chemical Reviews (2007); I. Billard, S. Mekki, C. Gaillard, P. Hesemann, C. Mariet, G. Moutiers, A. Labet, J.-C.G. Buenzli, European Journal of Inorganic Chemistry 6 (2004) 1190-1197; S. Samikkanu, K. Mellem, M. Berry, P.S. May, Inorganic Chemistry 46 (2007) 7121-7128]. The water in this ionic liquid system acts as a co-solvent to facilitate solubility of Tb 3+ and Eu 3+ compounds. The observed spectroscopic properties of Eu 3+ and Tb 3+ salts are expectedly impacted by the high water content, but unexpectedly impacted by the BMIBr ionic liquid. However, the spectroscopy of Eu(dpa) 3 3- is unaffected by the presence of BMIBr.

The isolation and the separation of Sm, Gd, Dy by extraction

International Nuclear Information System (INIS)

Biyantoro, D.; Lahagu, F.; Basuki, K.T.; Handini, T.; Rosyidin

1996-01-01

The isolation of yttrium and separation of Sm, Gd, y with extraction has been investigated. The steps of the process include of this research were the production the concentrate of lanthanide, the dilution, the isolation of yttrium, and the separation of the Sm, Gd, Dy. The first step was the digestion of xenotime sand, the extraction, the dilution, the filtration, the precipitation, the baking production a lanthanide oxide. The step was the separation of yttrium, the stripping, and the calcination production of yttrium oxide. And the third process was the separation of Sm, Gd, Dy by extraction process using method liquid-liquid extraction with extractant of D 2 EHPA and a solvent of dodecane. From the result have been found concentration of yttrium oxide = 88,71 %. The optimum condition of the separation of Gd/Dy have been found : the concentration of HNO 3 = 0,5 M, time of extraction = 15 minutes, and the concentration of extractant = 30 % D 2 EHPA in dodecane. The results of this condition were the distribution coefficient of Gd = 2,226, the distribution coefficient of Dy = 3,762, and the separation factor of Gd/Dy = 0,592. (author)

A role of copper(II) ions in the enhancement of visible and near-infrared lanthanide(III) luminescence

Energy Technology Data Exchange (ETDEWEB)

Eliseeva, Svetlana V., E-mail: svetlana.eliseeva@cnrs-orleans.fr [Centre de Biophysique Moléculaire CNRS UPR 4301, Rue Charles Sadron, 45071 Orléans Cedex 2 (France); Le Studium, Loire Valley Institute for Advanced Studies, 1 Rue Dupanloup, 45000 Orléans (France); Golovach, Iurii P.; Liasotskyi, Valerii S. [I.I.Mechnikov Odessa National University, 2 Dvoryanska street, 65082 Odessa (Ukraine); Antonovich, Valery P. [A.V. Bogatsky Physico-Chemical Institute of the National Academy of Sciences of Ukraine, 86 Lustdorfskaya doroga, 65080 Odessa (Ukraine); Petoud, Stéphane, E-mail: stephane.petoud@inserm.fr [Centre de Biophysique Moléculaire CNRS UPR 4301, Rue Charles Sadron, 45071 Orléans Cedex 2 (France); Meshkova, Svetlana B., E-mail: s_meshkova@ukr.net [A.V. Bogatsky Physico-Chemical Institute of the National Academy of Sciences of Ukraine, 86 Lustdorfskaya doroga, 65080 Odessa (Ukraine)

2016-03-15

Most of the existing optical methods for Cu{sup II} detection rely on a “turn-off” approach using visible lanthanide(III) luminescence. In this work we present an innovative molecular systems where the podands bis(2-hydrazinocarbonylphenyl) ethers of ethylene glycol (L1) and diethylene glycol (L2) have been designed, synthesised and tested with an ultimate goal to create a 'turn-on' lanthanide(III)-based molecular probe for the specific detection of Cu{sup II} ions based on both visible (Tb{sup III}, Eu{sup III}) and near-infrared (Nd{sup III}, Yb{sup III}) emission. Quantum yields of the characteristic Ln{sup III} emission signals increases by at least two-orders of magnitude upon addition of Cu{sup II} into water/acetonitrile (9/1) solutions of LnL (L=L1, L2) complexes. A detailed investigation of ligand-centred photophysical properties of water/acetonitrile (9/1) solutions of CuL, GdL and GdCuL complexes revealed that the presence of Cu{sup II} ions does not significantly affect the energy positions of the singlet (32,260 cm{sup −1}) and triplet (25,640–25,970 cm{sup −1}) states, but partially or fully eliminates the singlet state quenching through an electron transfer mechanism. This effect increases the probability of intersystem crossing leading to enhanced triplet-to-singlet emission ratio and to longer triplet state lifetimes. The redox activity of hydrazine moieties and their ability to reduce Cu{sup II} to Cu{sup I} has been indicated by a qualitative assay with neocuproine. Finally, the probe demonstrates a good selectivity towards Cu{sup II} over other transition metal ions: the addition of divalent Zn{sup II}, Cd{sup II}, Pd{sup II}, Ni{sup II}, Co{sup II} or trivalent Fe{sup III}, Ga{sup III}, In{sup III} ion salts into solutions of TbL either does not affect emission intensity or increases it to a maximum of 2–3 times, while, under similar experimental conditions, the presence of Cu{sup II} results in a 20- to 30-times

Nuclear magnetic resonance study of (Y[sub 1-x]R[sub x])[sub 2]Co[sub 14]B compounds (R=Gd, Tb)

Energy Technology Data Exchange (ETDEWEB)

Myojin, T. (Takamatsu National Coll. of Technology, Takamatsu (Japan)); Hayashi, M. (Takamatsu Coll. (Japan)); Ohno, T. (Faculty of Engineering, Tokushima Univ. (Japan)); Imaeda, Y. (Faculty of Engineering, Tokushima Bunri Univ., Shido (Japan)); Ushida, T. (Faculty of Engineering, Tokushima Bunri Univ., Shido (Japan)); Tsujimura, A. (Faculty of Engineering, Tokushima Bunri Univ., Shido (Japan)); Hihara, T. (Faculty of Integrated Arts and Sciences, Hiroshima Univ. (Japan))

1993-03-15

Influence of the Gd spin on the Co hyperfine field has been studied by [sup 59] Co nuclear magnetic resonance (NMR) in (Y[sub 1-x]Gd[sub x])[sub 2]Co[sub 14]B compounds. It is shown that the hyperfine coupling constants from the Gd spin for 8j[sub 1] and 8j[sub 2] sites are negative while those for 16k[sub 1] and 16k[sub 2] sites are positive. The dependence of the spin orientation temperature on the non-magnetic Y concentration in (Y[sub 1-x]Tb[sub x])[sub 2]Co[sub 14]B is also investigated by magnetization and [sup 59]Co NMR measurements. A spin phase diagram for this compound is proposed. (orig.)

Effect of lanthanide on the microstructure and structure of LnMn0.5Fe0.5O3 nanoparticles with Ln=La, Pr, Nd, Sm and Gd prepared by the polymer precursor method

International Nuclear Information System (INIS)

Romero, Mariano; Faccio, Ricardo; Martínez, Javier; Pardo, Helena; Montenegro, Benjamín; Plá Cid, Cristiani Campos; Pasa, André A.

2015-01-01

The synthesis of LnMn 0.5 Fe 0.5 O 3 perovskite nanoparticles by the polymer precursor method showed a strong intrinsic dependence with different lanthanides (Ln=La, Pr, Nd, Sm and Gd). The polymerization level reached in the polymer precursor was proportional to the atomic number of lanthanide with exception of samarium, which showed the formation of a different precursor based in a citrate chelate with ethyleneglycol bonded as adduct. The increasing level of polymerization of the polymer precursors showed the formation of large-size perovskite nanoparticles after its calcination. SAXS and TEM analyses suggested that nanoparticles obtained, using this method, have a squared-like microstructure in connection with the polymer precursor microstructure. Structural analysis showed an orthorhombic structure with a slight decline in the Jahn–Teller distortion when the atomic number of lanthanide increases. Mössbauer spectroscopy showed the presence of a majority site in agreement with the Pbnm orthorhombic structure best fitted with Rietveld refinements and in some cases, a more distorted site attributed to local inhomogeneities and oxygen vacancies. - Highlights: • Precursor polymerization level is lower in the presence of lighter lanthanides. • Lighter lanthanide perovskite nanoparticles after calcination are lower-sized. • Nanoparticles obtained by this method have lamellae microstructure. • Jahn–Teller distortion declines for heavier lanthanide perovskites. • Oxygen vacancy phase was observed in lighter lanthanide perovskites

Synthesis, crystal structures, and luminescent properties of two series' of new lanthanide (III) amino-carboxylate-phosphonates.

Science.gov (United States)

Zhou, Tian-Hua; Yi, Fei-Yan; Li, Pei-Xin; Mao, Jiang-Gao

2010-02-01

Hydrothermal reactions of lanthanide(III) chlorides with 4-HOOC-C(6)H(4)-CH(2)NHCH(2)PO(3)H(2) (H(3)L) at different ligand-to-metal (L/M) ratios afforded nine new lanthanide(III) carboxylate-phosphonates with two types of 3D network structures, namely, LnCl(HL)(H(2)O)(2) (Ln = Sm, 1; Eu, 2; Gd, 3; Tb, 4; Dy, 5; Er, 6) and [Ln(2)(HL)(H(2)L)(L)(H(2)O)(2)].4H(2)O (Ln = Nd, 7; Sm, 8; Eu, 9). Compounds 1-6 are isostructural and feature a 3D network in which the LnO(7)Cl polyhedra are interconnected by bridging CPO(3) tetrahedra into 2D inorganic layers parallel to the bc plane. These layers are further cross-linked by organic groups of the carboxylate-phosphonate ligands via the coordination of the carboxylate groups into a pillared-layered architecture. Compounds 7-9 are also isostructural and feature a 3D open-framework composed of 1D lanthanide(III) phosphonate inorganic slabs which are further bridged by organic groups of the carboxylate-phosphonate liagnds via the coordination of the carboxylate groups, forming large 1D tunnels along the b-axis which are filled by lattice water molecules. Luminescent measurements indicate that compounds 2, 4, and 5 show strong emission bands in red, green, and yellow light region, respectively. Magnetic properties of 2, 3, 5, and 7 have also been studied.

Complexes of light lanthanides with 2,4-dimethoxybenzoic acid

Directory of Open Access Journals (Sweden)

WIESLAWA FERENC

2000-01-01

Full Text Available The complexes of light lanthanides with 2,4-dimethoxybenzoic acid of the formula: Ln(C9H9O43·nH2O where Ln = La(III, Ce(III, Pr(III, Nd(III, Sm(III, Eu(III, Gd(IIII, and n = 3 for La(III, Gd(III, n = 2 for Sm(III, Eu(III, and n = 0 for Ce(III, Pr(III, Nd(III have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric studies and X-ray diffraction measurements. The complexes have colours typical for Ln3+ ions (La, Ce, Eu, Gd-white, Sm-cream, Pr-green, Nd-violet. The carboxylate group in these complexes is a symmetrical, bidentate, chelating ligand. They are crystalline compounds characterized by various symmetry. On heating in air to 1273 K the 2,4-dimethoxybenzoates of the light lanthanides decompose in various ways. The hydrated complexes decompose in two or three steps while those of anhydrous ones only in one or two. The trihydrate of lanthanum 2,4-dimethoxybenzoate first dehydrates to form the anhydrous salt, which then decomposes to La2O3via the intermediate formation of La2O2CO3. The hydrates of Sm(III, Eu(III, Gd(III decompose in two stages. First, they dehydrate forming the anhydrous salts, which then decompose directly to the oxides of the respective metals. The anhydrous complexes of Ce(III, Pr(III decompose in one step, while that of Nd(III in two. The solubilities of the 2,4-dimethoxybenzoates of the light lanthanides in water and ethanol at 293 K are in the order of: 10-3 mol dm-3 and 10-4-10-3 mol dm-3, respectively.

A study on the photographic characteristics related to the morphology of phosphor layers in the ca wo4 and gd2o2s : Tb screen

International Nuclear Information System (INIS)

Lee, In Ja; Huh, Joon

1993-01-01

Recently, various screen film system have been introduced in diagnostic radiology. There are two kinds of screen film system : blue emitting Ca WO 4 screen has been largely used in these days. However, it tends to be changed to use green emitting Gd 2 O 2 S : Tb screen. In this study, photographic characteristics of Ca WO 4 , and Gd 2 O 2 S : Tb screen were investigated with luminescence, spectroscopy. The morphology of Ca WO 4 , and Gd 2 O 2 S : Tb were also observed by using scanning electron microscope. The result obtained were as follows: 1. There was small difference in the thickness of phosphor layers for the front and back screen of blue emitting system, but little difference in those of green emitting system. 2. There was no difference in the size of phosphor particles between the front and back screen for each screen. However, the particle size was different for the various kinds of screens. 3. The shape of phosphor particle was round with many faces for all the screens. 4. In the exposure of X - ray with the same intensity, luminescent intensity of a green emitting system was 6∼7 times larger than that of a blue emitting system. 5. The thickness of phosphor layers does not affect on the sensitivity of the screens exposed by X - ray

Synthesis and characterization of metal soaps of lanthanides (III)

International Nuclear Information System (INIS)

Payolla, Filipe Boccato; Ribeiro, Sidney Jose Lima; Massbni, Antonio Carlos

2015-01-01

The present study describes synthesis and partial characterization of Eu"3"+, Nd"3"+, Dy"3"+, Tb"3"+ and Yb"3"+ behenate complexes. The compounds were analyzed using IR-Spectroscopy, TG-DTG, DSC, elemental analysis, XRD, luminescence and SEM. The results show the purity of the compounds. The XRD analysis and the SEM images show the high crystallinity of the complexes. TG-DTG and DSC analyses do not show a liquid crystal behavior, as occurs with other lanthanide metallic soaps. The mass loses until 1000° C show that the compounds lose ligand fragments at specific temperatures. XRD of the residues are compatible with the respective lanthanide oxides. The luminescence analysis shows that the Eu"3"+, Nd"3"+ and Tb"3"+ complexes presents appreciable emission. The Judd-Ofelt parameters obtained are compatible with the values found in the literature. It was not possible to obtain the complexes in a glass-form because it is difficult to prevent the crystallization of the complexes even using liquid nitrogen. The XDR data indicate that one of the complexes axis has 52 Å of length, agreeing with a structure containing behenate-lanthanide ion-behenate. The structures of the complexes were not fully elucidated and more analyses are necessary. The complexes presented a molar ratio of 3:1 (L:M) and were formulated as Bh_3Eu, Bh_3Nd, Bh_3Dy, Bh_3Tb e Bh_3Yb (Bh = behenate anion). (author)

New intermetallic compounds Ln(Ag, AL)4 (Ln-Y, Gd, Tb, Dy) and their structure

International Nuclear Information System (INIS)

Kuz'ma, Yu.B.; Stel'makhovich, B.M.

1990-01-01

By the methods of X-ray analysis crystal structure of compounds Ln(Ag,Al) 4 , where Ln-Y, Gd, Tb, Dy, posessing rhombic structure, is determined. The intermetallics have been prepared for the first time. Ways of atom distribution and their coordinates in DyAg 0.55 Al 3.45 structure (a=0.4296(1), b=04179(1), c=0.9995(3), R=0.093) are specified. Other compounds are formed in case of LnAgAl 3 compositions. Interatomic distances in Dy(Ag,Al) 4 structure are considered. A supposition is made on the formation in Ln-Ag-Al systems of a greater number of intermetallic compounds

Inkjet printing lanthanide doped nanorods test paper for visual assays of nitroaromatic explosives

International Nuclear Information System (INIS)

Hong, Liang; Mei, Qingsong; Yang, Lei; Zhang, Cheng; Liu, Renyong; Han, Mingyong; Zhang, Ruilong; Zhang, Zhongping

2013-01-01

Graphical abstract: -- Highlights: •A test paper was used for visualization of explosive 2,4,6-trinitrophenol (TNP) by the naked eye. •TNP can strongly quench the phosphorescence of NaGdF 4 :Ce/Tb nanorods. •Polyethylenimine (PEI) molecules facilitate the formation of uniform NaGdF 4 nanorods. •PEI molecules provide specific recognized sites for TNP by the acid–base pairing interaction. -- Abstract: The facile and sensitive strategies for detections of nitroaromatic explosives are highly desirable in many challenging environments, especially for homeland security against terrorism. Here, we inkjet printed polyethylenimine (PEI)-coated Ce, Tb co-doped NaGdF 4 nanorods (NaGdF 4 :Ce/Tb NRs) onto common filter paper to construct test paper for visual and instant detections of a typical explosive 2,4,6-trinitrophenol (TNP). Polyethylenimine molecules not only facilitate the formation of uniform NaGdF 4 nanorods but also provide specific recognized sites for TNP by the acid–base pairing interaction. The resultant TNP bound at the surface of PEI-coated NaGdF 4 :Ce/Tb NRs can strongly quench the phosphorescence with a remarkably high quenching constant by the charge transfer mechanism from NaGdF 4 :Ce/Tb NRs to TNP. By printing of the probe on a piece of filter paper, trace amounts of TNP can be visually detected by the appearance of a dark color against a bright green background under a UV lamp. This test paper can detect TNP as low as 0.45 ng mm −2 by the naked eye, which provides a potential application in the rapid, on-line detections of explosives

Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln==Sm, Eu, Gd) and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln==Tb, Dy, Ho)

Energy Technology Data Exchange (ETDEWEB)

Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian, E-mail: jiadingxian@suda.edu.cn

2013-10-15

Solvothermal reactions of Ln{sub 2}O{sub 3}, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln{sub 2}O{sub 3} oxides were converted to [Ln(dien){sub 2}]{sup 3+} complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS{sub 4} unit. In 1−3, the AsS{sub 4} units interconnect the [Ln(dien){sub 2}]{sup 3+} cations via Ln−S bonds as tridentate μ-1κ,2κ{sup 2}-AsS{sub 4} bridging ligands, resulting in the neutral coordination polymers [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln1). In 4−6, the AsS{sub 4} units coordinate with the Ln{sup 3+} ion of [Ln(dien){sub 2}]{sup 3+} as 1κ{sup 2}-AsS{sub 4} chelating ligands to form neutral coordination compounds [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln2). The Ln{sup 3+} ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln{sup 3+} ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] were prepared by solvothermal methods and the soft Lewis basic AsS{sub 4}{sup 3–} ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS{sub 4} ligand coordinate Ln{sup 3+} ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors

Inkjet printing lanthanide doped nanorods test paper for visual assays of nitroaromatic explosives

Energy Technology Data Exchange (ETDEWEB)

Hong, Liang [Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Mei, Qingsong [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Yang, Lei [Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Cheng; Liu, Renyong [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Han, Mingyong, E-mail: my-han@imre.a-star.edu.sg [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); ASTAR, Inst Mat Res and Engn, Singapore 117602 (Singapore); Zhang, Ruilong [Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zhang, Zhongping, E-mail: zpzhang@iim.ac.cn [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2013-11-13

Graphical abstract: -- Highlights: •A test paper was used for visualization of explosive 2,4,6-trinitrophenol (TNP) by the naked eye. •TNP can strongly quench the phosphorescence of NaGdF{sub 4}:Ce/Tb nanorods. •Polyethylenimine (PEI) molecules facilitate the formation of uniform NaGdF{sub 4} nanorods. •PEI molecules provide specific recognized sites for TNP by the acid–base pairing interaction. -- Abstract: The facile and sensitive strategies for detections of nitroaromatic explosives are highly desirable in many challenging environments, especially for homeland security against terrorism. Here, we inkjet printed polyethylenimine (PEI)-coated Ce, Tb co-doped NaGdF{sub 4} nanorods (NaGdF{sub 4}:Ce/Tb NRs) onto common filter paper to construct test paper for visual and instant detections of a typical explosive 2,4,6-trinitrophenol (TNP). Polyethylenimine molecules not only facilitate the formation of uniform NaGdF{sub 4} nanorods but also provide specific recognized sites for TNP by the acid–base pairing interaction. The resultant TNP bound at the surface of PEI-coated NaGdF{sub 4}:Ce/Tb NRs can strongly quench the phosphorescence with a remarkably high quenching constant by the charge transfer mechanism from NaGdF{sub 4}:Ce/Tb NRs to TNP. By printing of the probe on a piece of filter paper, trace amounts of TNP can be visually detected by the appearance of a dark color against a bright green background under a UV lamp. This test paper can detect TNP as low as 0.45 ng mm{sup −2} by the naked eye, which provides a potential application in the rapid, on-line detections of explosives.

Competing exchange interactions and their relevance for the magnetisation process in RMn6-xCrxSn6 powders (R=Y, Gd, Tb, Dy, Ho, Er)

International Nuclear Information System (INIS)

Brabers, J.H.V.J.; Zhou, G.F.; Colpa, J.H.P.; Buschow, K.H.J.; De Boer, F.R.

1994-01-01

The free-powder magnetisation of RMn 6-x Cr x Sn 6 compounds has been measured for compounds with R=Y, Gd, Tb, Dy, Ho, Er in fields up to 38 T, and interpreted in terms of a simple model, which is also outlined in this paper. From the measurements, estimates for the R-3d mean-field coupling constant (n RT ) could be derived for the cases where R=Gd, Tb, Dy, Ho, Er. In turn, the n RT values can be related to the microscopic spin-coupling constant (J RT ). In the case of YMn 6 Sn 6 the high-field measurement presents evidence for a very weak antiferromagnetic coupling between the Mn layers. Furthermore, values for the Mn moments (μ Mn ) were also derived from the magnetisation measurements. The estimated μ Mn values are of the order of 2.0 μ B . ((orig.))

Versatile lanthanide-azide complexes with azide/carboxylate/hydroxy mixed bridged chain exhibiting magnetic and luminescent properties

International Nuclear Information System (INIS)

Wang Haichao; Xue Min; Guo Qian; Zhao Jiongpeng; Liu Fuchen; Ribas, Joan

2012-01-01

Two new lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb for 1 and Tb for 2, isonic=isonicotinate), were obtained in hydrothermal condition. X-ray diffraction analysis indicated the two complexes are isomorphic chain structure in which the Ln III ions are mixed bridged by the azide anions, hydroxyl anions and carboxylate groups of the isonicotinate ligands. Further studies indicated weak antiferromagnetic interactions between the Ln III ions in 1 and 2, and complex 2 exhibit green sensitized Luminescent character of Tb III ion. - Graphical abstract: Two new 1D lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb III for 1 and Tb III for 2, isonic=isonicotinate), were synthesized by hydrothermal reaction and exhibit interesting magnetism and fluorescence properties. Highlights: ► The research provided a new method for synthesizing lanthanide-azide complexes. ► The complexes have an interesting azide/hydroxyl/carboxylate mixed bridged1D chain structure. ► The antiferromagnetic coupling between the complexes and 2 displays green luminescence.

Yb3+ can be much better than Dy3+: SMM properties and controllable self-assembly of novel lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes.

Science.gov (United States)

Gavrikov, Andrey V; Efimov, Nikolay N; Ilyukhin, Andrey B; Dobrokhotova, Zhanna V; Novotortsev, Vladimir M

2018-05-01

The first representatives of the binuclear lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes, namely isostructural compounds [Ln(dnbz)(acac)2(H2O)(EtOH)]2 (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), and Yb (8); dnbz - 3,5-dinitrobenzoate anion; acac - acetylacetonate (pentane-2,4-dionate) anion) were prepared and characterized. The SMM behavior of the Yb compound 8 was shown to be surprisingly less sensitive to the composition of the Yb3+ coordination environment in comparison with that of the Dy derivative. For Yb compound 8, the anisotropy barrier is Δeff/kB = 26 K under the dc field of 2000 Oe. This value is the highest one currently known for binuclear Yb complexes.

Crystal structure of RCoIn5 (R - Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y) and R2CoIn8 (R - Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Y) compounds

International Nuclear Information System (INIS)

Kalychak, Ya.M.; Zaremba, V.I.; Baranyak, V.M.; Bruskov, V.A.; Zavalij, P.Yu.

1989-01-01

Usng X-ray diffraction method of monocrystal, crystal structure of HoCoIn 5 compound belonging to the HoCoGa 5 structural type is determined. Using the method of powder belonging of CeCoIn 5 structure to the HoCoGa 5 structural type is confirmed. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Tb, Dy are detected. Their lattice periods are determined. Using the method of powder belonging of Ce 2 CoIn 8 compound structure to Ho 2 CoGa 8 structural type is determined. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm are detected and their lattice periods are determined

Thermal decomposition of RE(C2H5CO2)3·H2O (RE = Dy, Tb, Gd, Eu and Sm)

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2014-01-01

The thermal decomposition of Dy(III), Tb(III), Gd(III), Eu(III), and Sm(III) propionate monohydrates was studied in argon by means of simultaneous differential thermal analysis and thermogravimetry, infrared-spectroscopy, X-ray diffraction, and optical microscopy. After dehydration, which takes......, an intermediate stage involving a RE2O(C2H5CO2)4 composition was evidenced in the case of the Eu- and Sm-propionates. For all compounds, further decomposition of RE2O2CO3 into the corresponding sesquioxides (RE2O3) is accompanied by the release of CO2. The thermal decomposition of Dy- and Tb-propionates occurs...

Structural and magnetic properties of two branches of the tripod-kagome-lattice family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb)

Science.gov (United States)

Dun, Z. L.; Trinh, J.; Lee, M.; Choi, E. S.; Li, K.; Hu, Y. F.; Wang, Y. X.; Blanc, N.; Ramirez, A. P.; Zhou, H. D.

2017-03-01

We present a systematic study of the structural and magnetic properties of two branches of the rare-earth tripod-kagome-lattice (TKL) family A2R3Sb3O14 (A = Mg, Zn; R = Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb; here, we use abbreviation A-R, as in MgPr for Mg2Pr3Sb3O14 ), which complements our previously reported work on MgDy, MgGd, and MgEr [Z. L. Dun et al., Phys. Rev. Lett. 116, 157201 (2016), 10.1103/PhysRevLett.116.157201]. The present susceptibility (χdc, χac) and specific-heat measurements reveal various magnetic ground states, including the nonmagnetic singlet state for MgPr, ZnPr; long-range orderings (LROs) for MgGd, ZnGd, MgNd, ZnNd, and MgYb; a long-range magnetic charge ordered state for MgDy, ZnDy, and potentially for MgHo; possible spin-glass states for ZnEr, ZnHo; the absence of spin ordering down to 80 mK for MgEr, MgTb, ZnTb, and ZnYb compounds. The ground states observed here bear both similarities as well as striking differences from the states found in the parent pyrochlore systems. In particular, while the TKLs display a greater tendency towards LRO, the lack of LRO in MgHo, MgTb, and ZnTb can be viewed from the standpoint of a balance among spin-spin interactions, anisotropies, and non-Kramers nature of single-ion state. While substituting Zn for Mg changes the chemical pressure, and subtly modifies the interaction energies for compounds with larger R ions, this substitution introduces structural disorder and modifies the ground states for compounds with smaller R ions (Ho, Er, Yb).

Hetero-metallic {3d-4f-5d} complexes: preparation and magnetic behavior of trinuclear [(L(Me2)Ni-Ln){W(CN)(8)}] compounds (Ln = Gd, Tb, Dy, Ho, Er, Y; L(Me2) = Schiff base) and variable SMM characteristics for the Tb derivative.

Science.gov (United States)

Sutter, Jean-Pascal; Dhers, Sébastien; Rajamani, Raghunathan; Ramasesha, S; Costes, Jean-Pierre; Duhayon, Carine; Vendier, Laure

2009-07-06

Assembling bimetallic {Ni-Ln}(3+) units and {W(CN)(8)}(3-) is shown to be an efficient route toward heteronuclear {3d-4f-5d} compounds. The reaction of either the binuclear [{L(Me2)Ni(H(2)O)(2)}{Ln(NO(3))(3)}] complexes or their mononuclear components [L(Me2)Ni] and Ln(NO(3))(3) with (HNBu(3))(3){W(CN)(8)} in dmf followed by diffusion of tetrahydrofuran yielded the trinuclear [{L(Me2)NiLn}{W(CN)(8)}] compounds 1 (Ln = Y), 2a,b (Gd), 3a,b (Tb), 4 (Dy), 5 (Ho), and 6 (Er) as crystalline materials. All of the derivatives possess the trinuclear core resulting from the linkage of the {W(CN)(8)} to the Ni center of the {Ni-Ln} unit. Differences are found in the solvent molecules acting as ligands and/or in the lattice depending on the crystallization conditions. For all the compounds ferromagnetic {Ni-W} and {Ni-Ln} (Ln = Gd, Tb, Dy, and Er} interactions are operative resulting in high spin ground states. Parameterization of the magnetic behaviors for the Y and Gd derivatives confirmed the strong cyano-mediated {Ni-W} interaction (J(NiW) = 27.1 and 28.5 cm(-1)) compared to the {Ni-Gd} interaction (J(NiGd) = 2.17 cm(-1)). The characteristic features for slow relaxation of the magnetization are observed for two Tb derivatives, but these are modulated by the crystal phase. Analysis of the frequency dependence of the alternating current susceptibility data yielded U(eff)/k(B) = 15.3 K and tau(0) = 4.5 x 10(-7) s for one derivative whereas no maxima of chi(M)'' appear above 2 K for the second one.

Kinetics of electrophilic exchange of lanthanide(3) and copper(2) ions in aqueous solutions of ethylenediaminetetraacetates. [Rare earths: La,Pr,Nd,Eu,Gd,Tb,Er,Yb

Energy Technology Data Exchange (ETDEWEB)

Nikitenko, S.I.; Martynenko, L.I.; Pechurova, N.I.; Spitsyn, V.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

1984-05-01

Electrophilic exchange in the MA/sup -/ - Cu/sup 2 +/ (M/sup 3 +/=La/sup 3 +/, PUPSILON/sup 3 +/, Nd/sup 3 +/, Eu/sup 3 +/, Gd/sup 3 +/, Tb/sup 3 +/, Er/sup 3 +/, Yb/sup 3 +/, A/sup 4 -/=ethylenediaminetetraacetate) systems is studied. Copper is chosen as a constituent cation, because the stability of the CuA/sup 2 +/- complex is higher than that of the MA/sup -/ complex, besides the CuA/sup 2 -/, is characterized by a high extinction coefficient E/sub 280/=3200. Electrophilic exchange in the systems is shown to be realized through the acid dissociation mechanism and through the association mechanism. Consideration of the acid dissociation mechanism assumes that the exchange is limited by a break in the metal-oxygen bond in the intermediate protonated complex. In case of the association mechanism it is limited by a break in the metal-nitrogen bond in the intermediate binuclear complex. Rate constants of the limiting stage are calculated. Dependences of the rate constants of exchange on the stability of the complexes, the order number of the element, acidity of medium, Cu/sup 2 +/ concentration are given. Differences are shown to exist between the exchange mechanisms in the studied: systems for the REE of cerium and yttrium subgroups.

X-ray absorption and magnetic studies of trivalent lanthanide ions sorbed on pristine and phosphate-modified boehmite surfaces

International Nuclear Information System (INIS)

Yoon, Soh-Joung; Helmke, Philip A.; Amonette, James E.; Bleam, William F.

2002-01-01

The feasibility of immobilizing radionuclides on mineral surfaces was examined in the absence and the presence of phosphate anions, using trivalent lanthanide ions (Eu3+, Gd3+, and Dy3+) as chemical analogues of trivalent actinide radionuclides. The amount of the lanthanide ions (Ln3+) sorbed on boehmite (gamma-AlOOH) surfaces dramatically increased on the presence of phosphate below pH 5. The structure of the sorbed lanthanide was determined by X-ray absorption spectroscopy, magnetic susceptibility measurements, and electron paramagnetic resonance spectroscopy. We proved Dy3+ forms precipitates on boehmite surfaces in the presence of phosphate, and Gd3+ both in the presence and absence of phosphate. In the presence of phosphate, however, these rare-earth cations react to from ultrafine particles of LnPO4 surface precipitates on boehmite surfaces

A thermodynamical and structural study on the complexation of trivalent lanthanides with a polycarboxylate based concrete superplasticizer.

Science.gov (United States)

Fröhlich, Daniel R; Maiwald, Martin M; Taube, Franziska; Plank, Johann; Panak, Petra J

2017-03-21

The complexation of trivalent lanthanides with a commercial polycarboxylate based concrete superplasticizer (Glenium® 51) is investigated using different spectroscopic techniques. Time-resolved laser fluorescence spectroscopy (TRLFS) in combination with a charge neutralization model is used to determine temperature dependent conditional stability constants (log β'(T)) for the complexation of Eu(iii) with Glenium® 51 in 0.1 mol kg -1 NaCl solution in the temperature range of 20-90 °C. Only one complex species is observed, and log β'(T) (given in kg per mol eq) shows a very slight increase with temperature from 7.5 to 7.9. The related conditional molar reaction enthalpy (Δ r H' m ) and entropy (Δ r S' m ) obtained using the Van't Hoff equation show that the complexation reaction is slightly endothermic and entropy driven. The thermodynamic investigations are complemented by structural data for complexes formed with Gd(iii) or Tb(iii) and Glenium® 51 using extended X-ray absorption fine structure (EXAFS) spectroscopy. The results imply a non-chelate coordination of the trivalent metals through approximately three carboxylic functions of the polycarboxylate comb polymer which are attached predominantly in a bidentate fashion to the lanthanide under the given experimental conditions.

Synthesis and magnetic properties of CoFe2O4 spinel ferrite nanoparticles doped with lanthanide ions

International Nuclear Information System (INIS)

Kahn, Myrtil L.; Zhang, Z. John

2001-01-01

Lanthanide ions have been doped into cobalt spinel ferrites using an oil-in-water micellar method to form CoLn 0.12 Fe 1.88 O 4 nanoparticles with Ln=Ce, Sm, Eu, Gd, Dy, or Er. Doping with lanthanide ions (Ln III ) modulates the magnetic properties of cobalt spinel ferrite nanoparticles. In particular cases of Gd 3+ or Dy 3+ ions, a dramatic increase in the blocking temperature and coercivity is observed. Indeed, the introduction of only 4% of Gd 3+ ions increases the blocking temperature ∼100 K and the coercivity 60%. Initial studies on the magnetic properties of these doped nanoparticles clearly demonstrate that the relationship between the modulation of magnetic properties and the nature of doped Ln III ions is interesting but very complex. [copyright] 2001 American Institute of Physics

Rethinking Sensitized Luminescence in Lanthanide Coordination Polymers and MOFs: Band Sensitization and Water Enhanced Eu Luminescence in [Ln(C15H9O5)3(H2O)3]n (Ln = Eu, Tb).

Science.gov (United States)

Einkauf, Jeffrey D; Kelley, Tanya T; Chan, Benny C; de Lill, Daniel T

2016-08-15

A coordination polymer [Ln(C15H9O9)3(H2O)3]n (1-Ln = Eu(III), Tb(III)) assembled from benzophenonedicarboxylate was synthesized and characterized. The organic component is shown to sensitize lanthanide-based emission in both compounds, with quantum yields of 36% (Eu) and 6% (Tb). Luminescence of lanthanide coordination polymers is currently described from a molecular approach. This methodology fails to explain the luminescence of this system. It was found that the band structure of the organic component rather than the molecular triplet state was able to explain the observed luminescence. Deuterated (Ln(C15H9O9)3(D2O)3) and dehydrated (Ln(C15H9O9)3) analogues were also studied. When bound H2O was replaced by D2O, lifetime and emission increased as expected. Upon dehydration, lifetimes increased again, but emission of 1-Eu unexpectedly decreased. This reduction is reasoned through an unprecedented enhancement effect of the compound's luminescence by the OH/OD oscillators in the organic-to-Eu(III) energy transfer process.

Magnetic properties of Aurivillius lanthanide-bismuth (LnFeO3nBi4Ti3O12 (n = 1,2 layered titanates

Directory of Open Access Journals (Sweden)

Tartaj, J.

2008-06-01

Full Text Available Bismuth titanates of Aurivillius layer-structure (BiFeO3nBi4Ti3O12, are of great technological interest because of their applications as non-volatile ferroelectric memories and high-temperature piezoelectric materials. The synthesis and crystallographic characterization of a new family of compounds (LnFeO3nBi4Ti3O12 was recently reported, in which the layers consist of LnFeO3 perovskites with a lanthanide Ln3+ substituting diamagnetic Bi3+. We report herein the magnetic properties of bulk samples, with Ln = Nd, Eu, Gd and Tb, and n = 1 and 2. Single-layer materials are paramagnetic, similar to non-substituted bismuth titanate Bi5FeTi3O15, and show crystal field effects due to the crystallographic environment of Eu3+ and Tb3+. Several anomalies are detected in the magnetization M(T of double-layer (LnFeO32Bi4Ti3O12 compounds, related to the strong magnetism of Tb and Gd, since they weakly appear for Nd and they are absent in the VanVleck Eu3+ ion and in the parent Bi6Fe2Ti3O18 compound.Los titanatos de hierro y bismuto con estructura laminar tipo Aurivillius, (BiFeO3nBi4Ti3O12, tienen un gran interés tecnológico debido a sus aplicaciones como memorias ferroeléctricas no volátiles y como piezoeléctrico cerámico de alta temperatura. La síntesis y la caracterización cristalina de una nueva familia de compuestos (LnFeO3nBi4Ti3O12 han sido recientemente reportadas, en la que el catión diamagnético Bi3+ ha sido sustituido por los paramagnéticos Ln3+ en los bloques de perovskita. Se estudian las propiedades magnéticas de muestras cerámicas en volumen con Ln = Nd, Eu, Gd y Tb, y n = 1 y 2. Los materiales con n=1 son paramagnéticos y similares al no sustituido Bi5FeTi3O15, y muestran efectos de campo cristalino debido al entorno cristalino de Eu3+ y Tb3+. Se han detectado algunas anomalías en la magnetización M(T de los compuestos n=2 (LnFeO32Bi4Ti3O12 que están relacionadas con el fuerte magnetismo de Tb y Gd, que aparecen d

Estimation of ultraviolet radiation dose using CaF2:Tb phosphor

International Nuclear Information System (INIS)

Fukuda, Y.; Ohtaki, H.; Owaki, S.

1996-01-01

To observe and estimate the dose of ultraviolet (UV) radiation in sunlight, the available thermoluminescence (TL) materials were studied. Several kinds of lanthanide elements were doped in pure CaF 2 powdered crystal and the properties of the Tl for UV were observed. The TL intensity from CaF 2 :Tb was the highest among the samples doped with various lanthanide elements, and form the TL emission spectra (380-540 nm) the TL is estimated to be due to inner transition of Tb 3+ . The peak wavelength of the TL excitation light was located approximately at 235 nm and light of a longer wavelength than 320 nm was unable to excite the TL. The ultraviolet response of CaF 2 :Tb depended on its sintering temperature. Even without γ ray pre-irradiation the CaF 2 :Tb sample with 1 h exposure to sunlight has enough sensitivity to estimate the change of UV. Seasonal change of UV intensity in sunlight was measured with this TLD during four months in 1993. The results agreed with that of other institutes in Japan. (author)

Novel room temperature ionic liquid for fluorescence enhancement of Eu3+ and Tb3+

International Nuclear Information System (INIS)

Shyamala Devi, V.; Maji, S.; Viswanathan, K.S.

2011-01-01

The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu 3+ and Tb 3+ . The fluorescence enhancement resulted from a sensitization of the lanthanide fluorescence by the benzoate anion of the ionic liquid, [bmim][BA], and a reduction in the non-radiative channels in the non-aqueous environment provided by the ionic liquid. However, the fluorescence enhancement of the lanthanides in the ionic liquid was limited due to the operation of the inner filter effect, which resulted from the strong absorption of the benzoate. The inner filter effect was minimized by observing the Eu 3+ fluorescence using a front face geometry and also by diluting the lanthanide-[bmim][BA] system, using another ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf 2 N]), as a solvent. In the case of Tb 3+ , the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb 3+ emission was therefore observed using delayed gated detection, where an appropriate delay was used to discriminate against the short lived emission from the ionic liquid. The large fluorescence enhancement due to ligand sensitized fluorescence observed with [bmim][BA] diluted in [bmim][Tf 2 N], leads to nanomolar detection of the lanthanides. This is, to the best of our knowledge, the first report of an ionic liquid being employed for ligand sensitized fluorescence enhancement of lanthanides. - Research highlights: →The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu 3+ and Tb 3+ is discussed in this paper. → This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. → The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. → The first point is achieved by the use of an anion capable

Fixation of carbon dioxide by macrocyclic lanthanide(III) complexes under neutral conditions producing self-assembled trimeric carbonato-bridged compounds with μ3-η2:η2:η2 bonding.

Science.gov (United States)

Bag, Pradip; Dutta, Supriya; Biswas, Papu; Maji, Swarup Kumar; Flörke, Ulrich; Nag, Kamalaksha

2012-03-28

A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+).

Preparation and photophysical properties of luminescent nanoparticles based on lanthanide doped fluorides (LaF3:Ce3+, Gd3+, Eu3+), obtained in the presence of different surfactants

International Nuclear Information System (INIS)

Runowski, Marcin; Lis, Stefan

2014-01-01

Highlights: • Synthesis of nanocrystalline lanthanide fluorides doped with Eu 3+ ions. • Inorganic nanomaterials exhibiting bright red luminescence. • Luminescence enhancement by energy transfer (ET) from Ce 3+ → Gd 3+ to Eu 3+ ions. • Decreased agglomeration and morphology control using organic modifiers/surfactants. • Absolute and relative quantum yield (QY) comparison. - Abstract: A series of nanomaterials composed of LaF 3 :Ce 3+ 10%, Gd 3+ 30%, Eu 3+ 1% was synthesized via a facile co-precipitation approach. The reaction between appropriate lanthanide (Ln 3+ ) and fluoride ions resulted in the formation of crystalline, Ln 3+ doped fluorides and was performed in the presence of a series of organic modifiers, acting as surfactants and anti-agglomeration agents. Modifiers such as polyacrylic acid (PAA), ethylenediaminetetraacetic acid (EDTA), citric acid and oleylamine most significantly influenced the morphology and spectroscopic properties of the products. The product obtained in the presence of PAA was composed of the smallest nanoparticles (ca. 5–6 nm), with narrow size/shape distribution. All fluorides synthesized exhibited intensive, bright red luminescence under UV irradiation (λ ex ≈ 250 nm), because of the presence of Eu 3+ ions in their structure. The efficient intensity of luminescence was a result of indirect excitation, via energy transfer (ET) phenomena occurring in the system (Ce 3+ → Gd 3+ → Eu 3+ ). The structure and morphology of the obtained nanomaterials were established by powder X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) measurements. Optical properties of the obtained compounds were studied and discussed on the basis of excitation emission spectra and luminescence decay curves. On the basis of the performed measurements, luminescence quantum yield (absolute and relative) and radiative lifetimes were calculated and analyzed. FT-IR spectroscopy was applied to examine the presence of molecules of

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

Energy Technology Data Exchange (ETDEWEB)

Mishra, A; Singh, M P; Singh, V K

1982-05-01

The nitrato-complexes, (Y(PyBzH)/sub 2/(NO/sub 3/)/sub 2/)NO/sub 3/.H/sub 2/O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole) are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm/sup -1/cm/sup 2/mol/sup -1/) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the positive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C/sub 2/v) and uncoordinated (D/sub 3/h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms.

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

International Nuclear Information System (INIS)

Mishra, A.; Singh, M.P.; Singh, V.K.

1982-01-01

The nitrato-complexes, [Y(PyBzH) 2 (NO 3 ) 2 ]NO 3 .H 2 O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole] are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm -1 cm 2 mol -1 ) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the terpositive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C 2 v) and uncoordinated (D 3 h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms. (author)

Hard X-ray MCD in GdNi/sub 5/ and TbNi/sub 5/ single crystals

CERN Document Server

Galera, R M

1999-01-01

XMCD experiments have been performed at the R L/sub 2,3/ and Ni K- edges on magnetically saturated single crystals of GdNi/sub 5/ and Tb Ni/sub 5/ ferromagnetic compounds. The spectra present huge and well structured dichroic $9 signals at both the R L/sub 2,3/ and the Ni K- edges. Structures from the quadrupolar (2p to 4f) transitions are clearly observed at the R L/sub 2,3/-edges. Though Ni is not magnetic, large intensities, up to 0.4, are measured at the $9 Ni K- edge. The Ni K-edge XMCD shows a three-peak structure which intensities dependent on the rare earth. (7 refs).

Determination of stability constants of lanthanides (III) with amino acids (Preprint No. AL-07)

International Nuclear Information System (INIS)

Patel, N.M.; Patel, P.M.; Patel, M.N.; Joshi, J.D.

1989-01-01

The present paper reports the stability constants of La(III), Ce(III), Pr(III), Nd(III), Sm(III) and Gd(III) with amino acids valine, serine, threonine, methionine and aspartic acid. The coordination of valine and aspartic acid have been discussed. The stability constants of trivalent lanthanide amino acid complexes were found to be in the order, La < Ce < Pr < Nd < Sm < Gd. (author). 5 refs

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

International Nuclear Information System (INIS)

Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

2007-01-01

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

Luminescence studies on Sb3+ co-doped Y2Sn2O7: Tb nanoparticles

International Nuclear Information System (INIS)

Nigam, Sandeep; Sudarsan, V.; Vatsa, R.K.

2008-01-01

Pyrochlore-type oxides (A 2 B 2 O 7 ) have emerged as important host matrices for lanthanide doped luminescent materials due to their good thermal stability. Due to the higher symmetry around the A and B cations in the lattice lanthanide ions like Eu 3+ and Tb 3+ when incorporated at the A or B sites give very poor luminescence. One way to circumvent this problem is to incorporate ions like Sb 3+ or Bi 3+ in the lattice so that the lattice get distorted and luminescent intensity from the lanthanide ions increases. The present study deals with the synthesis and characterisation of Sb 3+ co-doped Y 2 Sn 2 O 7 :Tb nanoparticles prepared by the hydrolysis of Y 3+ , Sn 4+ , Tb 3+ and Sb 3+ in ethylene glycol medium followed by heating at 700 deg C for 4 hours. From XRD studies it is confirmed that as prepared sample is amorphous and heat treatment at 700 deg C results in the formation of highly crystalline Y 2 Sn 2 O 7 phase having pyrochlore structure

Benchmarking Pt and Pt-lanthanide sputtered thin films for oxygen electroreduction

DEFF Research Database (Denmark)

Zamburlini, Eleonora; Jensen, Kim Degn; Stephens, Ifan E.L.

2017-01-01

Platinum-lanthanide alloys are very promising as active and stable catalysts for the oxygen reduction reaction (ORR) in low-temperature fuel cells. We have fabricated Pt and Pt5Gd metallic thin films via (co-)sputtering deposition in an ultra-high vacuum (UHV) chamber. The electrochemical ORR...

Luminescent Lanthanide Metal Organic Frameworks for cis-Selective Isoprene Polymerization Catalysis

Directory of Open Access Journals (Sweden)

Samantha Russell

2015-11-01

Full Text Available In this study, we are combining two areas of chemistry; solid-state coordination polymers (or Metal-Organic Framework—MOF and polymerization catalysis. MOF compounds combining two sets of different lanthanide elements (Nd3+, Eu3+/Tb3+ were used for that purpose: the use of neodymium was required due to its well-known catalytic properties in dienes polymerization. A second lanthanide, europium or terbium, was included in the MOF structure with the aim to provide luminescent properties. Several lanthanides-based MOF meeting these criteria were prepared according to different approaches, and they were further used as catalysts for the polymerization of isoprene. Stereoregular cis-polyisoprene was received, which in some cases exhibited luminescent properties in the UV-visible range.

Polymerization of lanthanide acrylonitrile complexes.

Science.gov (United States)

el-Mossalamy, El-Sayed H; Khalil, Ahmed A

2002-01-01

The molecular complexes of some lanthanides scandium (Sc3+), yttrium (Y3+), lanthanum (La3+), gadolinium (Gd3+), cerium (Ce3+) and ytterbium (Yb3) have been studies in dimethyl formamide (DMF) spectrophtometrically equilibrium constants (K), molar extintion coefficient (epsilon), energy of transition (E) and free energy (delta G*) were calculated. The polymerization of acrylonitrile has been studied and investigated in the presence of Sc3+, Y3+, La3+, Gd3+, Ce3+, and Yb3+ ions. The IR spectra of the formed AN-M (III) Br3 polymer complexes show the absence of the C identical to N band and the presence of two new bands corresponding to NH2 and OH groups. Magnetic moment values and the thermal stabilities of homopolymer and the polymer complexes were studied by means of thermogravimetric analysis and the activation energies for degradation were calculated.

Luminescent hybrid materials functionalized with lanthanide ethylenodiaminotetraacetate complexes containing β-diketonate as antenna ligands

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Franklin P.; Costa, Israel F.; Espínola, José Geraldo P.; Faustino, Wagner M.; Moura, Jandeilson L. [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Brito, Hermi F.; Paolini, Tiago B. [Departamento de Química Fundamental-Instituto de Química da Universidade de São Paulo, 05508-900 São Paulo, SP (Brazil); Felinto, Maria Cláudia F.C. [Instituto de Pesquisas energéticas e Nucleares-IPEN, 05508-900 São Paulo, SP (Brazil); Teotonio, Ercules E.S., E-mail: teotonioees@quimica.ufpb.br [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)

2016-02-15

Three organic–inorganic hybrid materials based on silica gel functionalized with (3-aminopropyl)trimethoxysilane (APTS), [3-(2-aminoetilamino)-propil]-trimetoxissilano (DAPTS) and 3-[2-(2-aminoetilamino)etilamino] propiltrimetoxysilane (TAPTS) and subsequently modified with EDTA derivative were prepared by nonhomogeneous route and were then characterized. The resulting materials named SilXN-EDTA (X=1 for APTS, 2 for DAPTS and 3 for TAPTS) were used to obtain new lanthanide Ln{sup 3+}-β-diketonate (Ln{sup 3+}=Eu{sup 3+}, Gd{sup 3+} and Tb{sup 3+}) complexes covalently linked to the functionalized silica gel surfaces (named SilXN-EDTALn-dik, dik=tta, dbm, bzac and acac). The photophysical properties of the new luminescent materials were investigated and compared with those with similar system presenting water molecules coordinated to the lanthanide ions, SilXN-EDTALn-H{sub 2}O. The SilXN-EDTAEu-dik and SilXN-EDTATb-dik systems displayed characteristic red and green luminescence when excited by UV radiation. Furthermore, the quantitative results showed that the emission quantum efficiency (η), experimental intensity parameters Ω{sub 2} and Ω{sub 4}, and Einstein's emission coefficient (A{sub 0J}) of the SilXN-EDTAEu-dik materials were largely dependent on the ligands. Based on the luminescence data, the most efficient intramolecular energy transfer processes were found to the SilXN-EDTAEu-dik (dik: tta and dbm) and SilXN-EDTATb-acac materials, which exhibited more pure emission colors. These materials are promising red and green phosphors, respectively. - Highlights: • New highly luminescent hybrid materials containing lanthanide-EDTA complexes. • The effect of three silylanting agent on the adsorption and luminescent properties has been studied. • The luminescence sensitizing by different β-diketonate ligands have been investigated.

Structural trends in a series of isostructural lanthanide-copper metallacrown sulfates (Ln(III) = Pr, Nd, Sm, Eu, Gd, Dy and Ho): hexaaquapentakis[μ3-glycinehydroxamato(2-)]sulfatopentacopper(II)lanthanide(III) heptaaquapentakis[μ3-glycinehydroxamato(2-)]sulfatopentacopper(II)lanthanide(III) sulfate hexahydrate.

Science.gov (United States)

Pavlishchuk, Anna V; Kolotilov, Sergey V; Fritsky, Igor O; Zeller, Matthias; Addison, Anthony W; Hunter, Allen D

2011-07-01

The seven isostructural complexes, [Cu(5)Ln(C(2)H(4)N(2)O(2))(5)(SO(4))(H(2)O)(6.5)](2)(SO(4))·6H(2)O, where Ln(III) = Pr, Nd, Sm, Eu, Gd, Dy and Ho, are representatives of the 15-metallacrown-5 family. Each dianion of glycinehydroxamic acid (GlyHA) links two Cu(II) cations forming a cyclic [CuGlyHA](5) frame. The Ln(III) cations are located at the centre of the [CuGlyHA](5) rings and are bound by the five hydroxamate O atoms in the equatorial plane. Five water molecules are coordinated to Cu(II) cations, and one further water molecule, located close to an inversion centre between two adjacent [Cu(5)Ln(GlyHA)(5)](2+) cations, is disordered around this inversion centre and coordinated to a Cu(II) cation of either the first or second metallacrown ether. Another water molecule and one of the two crystallographically independent sulfate anions are coordinated, the latter in a bidentate fashion, to the Ln(III) cation in the axial positions. The second sulfate anion is not coordinated to the cation, but is located in an interstitial position on a crystallographic inversion centre, thus leading to disorder of the O atoms around the centre of inversion. The Ln-O bond distances follow the trend of the lanthanide contraction. The apical Ln-O bond distances are very close to the sums of the ionic radii. However, the Ln-O distances within the metallacrown units are slightly compressed and the Ln(III) cations protrude significantly from the plane of the otherwise flat metallacrown ligand, thus indicating that the cavity is somewhat too small to accommodate the Ln(III) ions comfortably. This effect decreases with the size of the lanthanide cation from complex (I) (Ln(III) = Pr; 0.459) to complex (VII) (Ln(III) = Ho; 0.422), which indicates that the smaller lanthanide cations fit the cavity of the pentacopper metallacrown ring better than the larger ones. The diminished contraction of Ln-O distances within the metallacrown planes leads to an aniostropic contraction of the unit

Study on the fabrication and photoluminescence characteristics of LiPO3 glass scintillators with the lanthanides activators

International Nuclear Information System (INIS)

Jeong, S. Z.; Lee, J. M.; Hwang, J. H.; Choi, S. H.

2001-01-01

In this syudy, LiPO 3 glass scintillators were fabricated, and lanthanides (except Pm) oxides or chlorides were used as an activator. For the fabrication of LiPO 3 glasses, optimum heating conditions were obtained, and the photoluminescence of the glasses was measured by the monochromator. For the best transparency of the glass samples, optimum heating temperature and time is 950 .deg. C and 90 min, respectively. As the result of photoluminescence analysis, it was impossible to apply Pr, Nd, Gd, Ho, Er, Tm, Yb, and Lu to activator. Because emission spectrum of samples with them was equal to that of sample without activator. In case of samples with Europium, the peak of emission spectrum of Eu(II) and Eu(III) is 420 nm and 620 nm, separately. And Samples with Ce(III) are about 380 nm, and Tb(III) are about 550 nm. On the fabrication of LiPO 3 glass samples, PL intensity was increased by adding sugar as reductant, and using Ar reduction atmosphere. And the optimum reduction conditions were differed as to the kinds of activators. Samples with Eu(II) and Tb(III) have the best PL intensity in the Ar reduction atmosphere, and sample with Ce(III) have the best intensity by added sugar

High-pressure syntheses of lanthanide polysulfides and polyselenides LnX_1_._9 (Ln = Gd-Tm, X = S, Se)

International Nuclear Information System (INIS)

Mueller, Carola J.; Schwarz, Ulrich; Doert, Thomas

2012-01-01

The polysulfides LnS_1_._9 and polyselenides LnSe_1_._9 of the lanthanide metals from gadolinium to thulium were prepared by high-pressure high-temperature synthesis. The compounds adopt the tetragonal CeSe_1_._9 structure type in space group P4_2/n (No. 86) with lattice parameters of 8.531 Aa ≤ a ≤ 8.654 Aa and 15.563 Aa ≤ c ≤ 15.763 Aa for the sulfides and 8.869 Aa ≤ a ≤ 9.076 Aa and 16.367 Aa ≤ c ≤ 16.611 Aa for the selenides. The atomic pattern consists of puckered double slabs [LnX]"+ and planar chalcogenide layers with ten possible chalcogen positions, of which eight are occupied by chalcogen atoms forming dinuclear X_2"2"- dianions, one by a single X"2"- ion and one remaining vacant. This resembles a √5 x √5 x 2 superstructure of the ZrSSi aristotype. Structural relationships to the aristotype and the related lanthanide polychalcogenides LnX_2_-_δ (Ln = La-Tm, X = S-Te, δ = 0 - 0.3) are discussed. The samples synthesized under high-pressure conditions (p > 1 GPa) decompose slowly under release of sulfur or selenium at ambient conditions. The crystal structure of a partially degraded thulium-polysulfide sample can be described as an incommensurate variant of the original TmS_1_._9 motif. Additionally, the isostructural ternary compound Gd(S_1_-_xSe_x)_1_._9 was synthesized and characterized by powder X-ray diffraction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

X-ray excited photoluminescence near the giant resonance in solid-solution Gd1-xTbxOCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd1-xTbxF3

Science.gov (United States)

Waetzig, Gregory R.; Horrocks, Gregory A.; Jude, Joshua W.; Zuin, Lucia; Banerjee, Sarbajit

2015-12-01

Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb3+ centers upon X-ray excitation near the giant resonance of the host Gd3+ ions.Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism

New magnetic refrigeration materials for the liquefaction of hydrogen

International Nuclear Information System (INIS)

Gschneidner, K.A.; Takeya, H.; Moorman, J.O.; Pecharsky, V.K.; Malik, S.K.; Zimm, C.B.

1994-01-01

Five heavy lanthanide ferromagnetic intermetallic compounds were studied as potential magnetic refrigerants for the liquefaction of hydrogen gas. (Dy 0.5 Er 0.5 )Al 2 and TbNi 2 appear to be better refrigerants than GdPd for a Joule-Brayton cycle refrigerator, while (Gd 0.54 Er 0.46 )AlNi seems to be a suitable refrigerant for an Ericsson cycle refrigerator

Valence determination of rare earth elements in lanthanide silicates by L 3-XANES spectroscopy

International Nuclear Information System (INIS)

Kravtsova, Antonina N; Guda, Alexander A; Soldatov, Alexander V; Goettlicher, Joerg; Taroev, Vladimir K; Suvorova, Lyudmila F; Tauson, Vladimir L; Kashaev, Anvar A

2016-01-01

Lanthanide silicates have been hydrothermally synthesized using Cu and Ni containers. Chemical formulae of the synthesized compounds correspond to K 3 Eu[Si 6 O 15 ] 2H 2 O, HK 6 Eu[Si 10 O 25 ], K 7 Sm 3 [Si 12 O 32 ], K 2 Sm[AlSi 4 O 12 ] 0.375H 2 O, K 4 Yb 2 [Si 8 O 21 ], K 4 Ce 2 [Al 2 Si 8 O 24 ]. The oxidation state of lanthanides (Eu, Ce, Tb, Sm, Yb) in these silicates has been determined using XANES spectroscopy at the Eu, Ce, Tb, Sm, Yb, L 3 - edges. The experimental XANES spectra were recorded using the synchrotron radiation source ANKA (Karlsruhe Institute of Technology) and the X-ray laboratory spectrometer Rigaku R- XAS. By comparing the absorption edge energies and white line intensities of the silicates with the ones of reference spectra the oxidation state of lanthanides Eu, Ce, Tb, Sm, Yb has been found to be equal to +3 in all investigated silicates except of the Ce-containing silicate from the run in Cu container where the cerium oxidation state ranges from +3 (Ce in silicate apatite and in a KCe silicate with Si 12 O 32 layers) to +4 (starting CeO 2 or oxidized Ce 2 O 3 ). (paper)

Novel room temperature ionic liquid for fluorescence enhancement of Eu{sup 3+} and Tb{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Shyamala Devi, V.; Maji, S. [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.i [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

2011-04-15

The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu{sup 3+} and Tb{sup 3+}. The fluorescence enhancement resulted from a sensitization of the lanthanide fluorescence by the benzoate anion of the ionic liquid, [bmim][BA], and a reduction in the non-radiative channels in the non-aqueous environment provided by the ionic liquid. However, the fluorescence enhancement of the lanthanides in the ionic liquid was limited due to the operation of the inner filter effect, which resulted from the strong absorption of the benzoate. The inner filter effect was minimized by observing the Eu{sup 3+} fluorescence using a front face geometry and also by diluting the lanthanide-[bmim][BA]system, using another ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf{sub 2}N]), as a solvent. In the case of Tb{sup 3+}, the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb{sup 3+} emission was therefore observed using delayed gated detection, where an appropriate delay was used to discriminate against the short lived emission from the ionic liquid. The large fluorescence enhancement due to ligand sensitized fluorescence observed with [bmim][BA]diluted in [bmim][Tf{sub 2}N], leads to nanomolar detection of the lanthanides. This is, to the best of our knowledge, the first report of an ionic liquid being employed for ligand sensitized fluorescence enhancement of lanthanides. - Research highlights: {yields}The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu{sup 3+} and Tb{sup 3+} is discussed in this paper. {yields} This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. {yields} The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. {yields

Basic TRLFS data of some lanthanides using a tunable laser system and a red-optimized detection system

Energy Technology Data Exchange (ETDEWEB)

Heller, Anne [Dresden Technische Univ. (Germany). Inst. for Zoology, Molecular Cell Physiology and Endocrinology; Barkleit, Astrid [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Chemistry of the F-Elements; Geipel, Gerhard [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Biogeochemistry

2016-07-01

Lanthanides are crucial raw materials for modern high-tech products and used in medicine, especially as contrast enhancing agents for magnetic resonance imaging [1]. To study their interactions in the geo- and biosphere, Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS), which is a non-invasive, very sensitive, and versatile state of the art method, is used. Up to now, TRLFS is well established for actinides but only some lanthanides (especially Eu and Tb). To extent this scope, we investigate the basic luminescence properties of all lanthanide elements.

The low-energy β(-) and electron emitter (161)Tb as an alternative to (177)Lu for targeted radionuclide therapy.

Science.gov (United States)

Lehenberger, Silvia; Barkhausen, Christoph; Cohrs, Susan; Fischer, Eliane; Grünberg, Jürgen; Hohn, Alexander; Köster, Ulli; Schibli, Roger; Türler, Andreas; Zhernosekov, Konstantin

2011-08-01

The low-energy β(-) emitter (161)Tb is very similar to (177)Lu with respect to half-life, beta energy and chemical properties. However, (161)Tb also emits a significant amount of conversion and Auger electrons. Greater therapeutic effect can therefore be expected in comparison to (177)Lu. It also emits low-energy photons that are useful for gamma camera imaging. The (160)Gd(n,γ)(161)Gd→(161)Tb production route was used to produce (161)Tb by neutron irradiation of massive (160)Gd targets (up to 40 mg) in nuclear reactors. A semiautomated procedure based on cation exchange chromatography was developed and applied to isolate no carrier added (n.c.a.) (161)Tb from the bulk of the (160)Gd target and from its stable decay product (161)Dy. (161)Tb was used for radiolabeling DOTA-Tyr3-octreotate; the radiolabeling profile was compared to the commercially available n.c.a. (177)Lu. A (161)Tb Derenzo phantom was imaged using a small-animal single-photon emission computed tomography camera. Up to 15 GBq of (161)Tb was produced by long-term irradiation of Gd targets. Using a cation exchange resin, we obtained 80%-90% of the available (161)Tb with high specific activity, radionuclide and chemical purity and in quantities sufficient for therapeutic applications. The (161)Tb obtained was of the quality required to prepare (161)Tb-DOTA-Tyr3-octreotate. We were able to produce (161)Tb in n.c.a. form by irradiating highly enriched (160)Gd targets; it can be obtained in the quantity and quality required for the preparation of (161)Tb-labeled therapeutic agents. Copyright © 2011 Elsevier Inc. All rights reserved.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

Energy Technology Data Exchange (ETDEWEB)

Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

2007-10-15

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy; Investigacao do magnetismo local em compostos intermetalicos do tipo RZn (R = Ce, Gd, Tb, Dy) e GdCu pela espectroscopia de correlacao angular gama-gama perturbada

Energy Technology Data Exchange (ETDEWEB)

Santos, Brianna Bosch dos

2010-07-01

This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with {sup 111}In {yields} {sup 111}Cd and {sup 140}La {yields} {sup 140}Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei {sup 140}La {yields} {sup 140}Ce is interesting because Ce{sup +3} ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for {sup 111}Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with {sup 111}Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with {sup 111}Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

Analysis of green luminescent Tb3+:Ca4GdO(BO3)3 powder phosphor

International Nuclear Information System (INIS)

Vengala Rao, B.; Rambabu, U.; Buddhudu, S.

2007-01-01

This paper reports on the emission analysis of a green luminescent Tb 3+ :Ca 4 GdO(BO 3 ) 3 powder phosphor based on the measurements of excitation, emission and lifetimes. Besides this, we have also observed an intense green emission from this powder phosphor under an UV source. The emission transitions of ( 5 D 4 →7 F 3,4,5,6 ) with λ exci =257 nm have been measured. Particularly, the green emission transition ( 5 D 4 →7 F 5 ) at 553 nm has been found to be more prominent and intense. Such green strong emission displaying powder phosphor will find applications in the development of coated screens in certain electronic systems. Apart from the emission analysis of this phosphor, XRD, SEM and FTIR studies have also been carried out in order to understand the structural details of it

Preparation and studies of Eu{sup 3+} and Tb{sup 3+} co-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} sol-gel scintillating films

Energy Technology Data Exchange (ETDEWEB)

Morales Ramirez, A. de J, E-mail: amoralesra@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA) Unidad Altamira Instituto Politecnico Nacional Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Garcia Murillo, A.; Carrillo Romo, F. de J [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Ramirez Salgado, J. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas No. 152, CP 07730, Mexico D.F. (Mexico); Le Luyer, C. [LPCML, CNRS-UMR 5620/Universite Claude Bernard Lyon 1/69622 Villeurbanne Cedex (France); Chadeyron, G.; Boyer, D. [Laboratoire des Materiaux Inorganiques, CNRS-UMR 6002, Universite Blaise Pascal, 24 Ave des Landais F 63177 Aubiere Cedex (France); Moreno Palmerin, J. [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico)

2009-10-30

Eu{sup 3+} (2.5 at.%) and Tb{sup 3+} (0.005-0.01 at.%) co-doped gadolinium and yttrium oxide (Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3}) powders and films have been prepared using the sol-gel process. High density and optical quality thin films were prepared with the dip-coating technique. Gadolinium (III) 2,4-pentadionate and yttrium (III) 2,4-pentadionate were used as precursors, and europium and terbium in their nitrate forms were used as doping agents. Chemical and structural analyses (infrared spectroscopy, X-ray diffraction and high-resolution transmission electron microscopy) were conducted on both sol-gel precursor powders and dip-coated films. The morphology of thin films heat-treated at 700 {sup o}C was studied by means of atomic force microscopy. It was shown that the highly dense and very smooth films had a root mean roughness (RMS) of 2 nm {+-} 0.2 (A = 0.0075 Tb{sup 3+}) and 24 nm {+-} 3.0 (B = 0.01 Tb{sup 3+}). After treatment at 700 {sup o}C, the crystallized films were in the cubic phase and presented a polycrystalline structure made up of randomly oriented crystallites with grain sizes varying from 20 to 60 nm. The X-ray induced emission spectra of Eu{sup 3+}- and Tb{sup 3+}-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} powders showed that Tb{sup 3+} contents of 0.005, 0.0075 and 0.01 at.% affected their optical properties. Lower Tb{sup 3+} concentrations (down to 0.005 at.%) in both systems enhanced the light yield.

Synthesis, structure and luminescence properties of binary and ternary complexes of lanthanide (Eu{sup 3+}, Sm{sup 3+} and Tb{sup 3+}) with salicylic acid and 1,10-phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Shen, Chen-Qi; Yan, Tian-Lu; Wang, Yi-Ting; Ye, Zi-Jun; Xu, Cun-Jin, E-mail: cjxu@hznu.edu.cn; Zhou, Wen-Jun

2017-04-15

A series of binary and ternary complexes of lanthanide (Eu{sup 3+}, Sm{sup 3+} and Tb{sup 3+}) with salicylic acid (Hsal) and 1,10-phenanthroline (phen) were synthesized, and characterized by element analysis, coordination titration analysis, IR, UV and TG-DTA. Their compositions were (NH{sub 4})[Ln(sal){sub 4}(H{sub 2}O){sub 2}] (Ln=Eu (1), Sm (2), Tb (3)) and (NH{sub 4})[Ln(sal){sub 4}(phen){sub 2}] (Ln=Eu (4), Sm (5), Tb (6)), respectively. In particular, the ternary complex of Eu{sup 3+}, 4, was characterized by X-ray diffraction, and luminescence intensities of binary and ternary complexes were compared. In case of Eu{sup 3+} and Sm{sup 3+} complexes, ternary complexes emitted stronger luminescence than corresponding binary complexes of salicylic acid and Ln{sup 3+}. On the other hand, the ternary Tb{sup 3+} complex had weaker luminescence than the binary complex because of back energy transfer from Tb{sup 3+} to phen. The CIE coordinates of 1–6 were calculated as (0.65, 0.35), (0.52, 0.48), (0.33, 0.59), (0.67, 0.33), (0.62, 0.38) and (0.36, 0.58), respectively, which enable these complexes to be promising candidates for red, green, or yellow component in OLEDs.

La(3+) and Gd(3+) induce shape change of giant unilamellar vesicles of phosphatidylcholine.

Science.gov (United States)

Tanaka, Tomoki; Tamba, Yukihiro; Masum, Shah Md; Yamashita, Yuko; Yamazaki, Masahito

2002-08-19

Lanthanides such as La(3+) and Gd(3+) are well known to have large effects on the function of membrane proteins such as mechanosensitive ionic channels and voltage-gated sodium channels, and also on the structure of phospholipid membranes. In this report, we have investigated effects of La(3+) and Gd(3+) on the shape of giant unilamellar vesicle (GUV) of dioleoylphosphatidylcholine (DOPC-GUV) and GUV of DOPC/cholesterol by the phase-contrast microscopy. The addition of 10-100 microM La(3+) (or Gd(3+)) through a 10-microm diameter micropipette near the DOPC-GUV (or DOPC/cholesterol-GUV) triggered several kinds of shape changes. We have found that a very low concentration (10 microM) of La(3+) (or Gd(3+)) induced a shape change of GUV such as the discocyte via stomatocyte to inside budded shape transformation, the two-spheres connected by a neck to prolate transformation, and the pearl on a string to cylinder (or tube) transformation. To understand the effect of these lanthanides on the shape of the GUV, we have also investigated phase transitions of 30 microM dipalmitoylphosphatidylcholine-multilamellar vesicle (DPPC-MLV) by the ultra-sensitive differential scanning calorimetry (DSC). The chain-melting phase transition temperature and the L(beta') to P(beta') phase transition temperature of DPPC-MLV increased with an increase in La(3+) concentration. This result indicates that the lateral compression pressure of the membrane increases with an increase in La(3+) concentration. Thereby, the interaction of La(3+) (or Gd(3+)) on the external monolayer membrane of the GUV induces a decrease in its area (A(ex)), whereas the area of the internal monolayer membrane (A(in)) keeps constant. Therefore, the shape changes of the GUV induced by these lanthanides can be explained reasonably by the decrease in the area difference between two monolayers (DeltaA=A(ex)-A(in)).

Optical emission, vibrational feature, and shear-thinning aspect of Tb3+-doped Gd2O3 nanoparticle-based novel ferrofluids irradiated by gamma photons

Science.gov (United States)

Paul, Nibedita; Hazarika, Samiran; Saha, Abhijit; Mohanta, Dambarudhar

2013-10-01

The present work reports on the spectroscopic and rheological properties of un-exposed and gamma (γ-) irradiated rare earth (RE) oxide nanoparticle-based ferrofluids (FFs). The FFs were produced by dispersing surfactant coated terbium (Tb3+)-doped gadolinium oxide (Gd2O3) nanoparticles in the ethanol medium and later on they were subjected to energetic γ-irradiation (1.25 MeV) at select doses (97 Gy and 2.635 kGy). The synthesized RE oxide nanoparticles were of ˜7 nm size and having a cubic crystal structure, as predicted from transmission electron microscopy and x-ray diffraction studies. Fourier transformed infra-red (FT-IR) spectra showed an adequate blue shift of the Gd-O vibrational stretching mode from a wavenumber value of ˜558 cm-1, for the un-irradiated sample to a value of ˜540 cm-1 corresponding to the irradiated sample (2.635 kGy). In contrast, photoluminescence spectra have revealed modification of defect states along with Tb3+ assisted radiative transitions. The rheology measurements have illustrated unusual shear thinning behavior of the FFs, with an apparently improved power index (s) value from 0.34 to 0.50, obtained for increasing γ-dose cases. The variation of the decay parameter with irradiation dose, as predicted from the nature of apparent viscosity curves, is attributed to the defect formation, role of impurity ions (Tb3+), and weakening of inter nanoparticle bonding. The unusual properties of the novel RE oxide based FFs may find scope in sealing and shielding elements in the radiation environment including accelerator and other related zones.

Construction of three lanthanide metal-organic frameworks: Synthesis, structure, magnetic properties and highly selective sensing of metal ions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiu-Mei, E-mail: zhangxiumeilb@126.com; Li, Peng; Gao, Wei; Liu, Feng; Liu, Jie-Ping

2016-12-15

Three lanthanide metal-organic frameworks (Ln-MOFs), [Ln(TZI)(H{sub 2}O){sub 4}]·3H{sub 2}O (Ln=Gd (1) and Tb (2) and Dy (3), H{sub 3}TZI=5-(1H-tetrazol-5-yl)isophthalic acid), have been synthesized under hydrothermal conditions. Single crystal X-ray diffraction reveals that 1–3 are isostructural and display a 1D double chain based on dinuclear motifs with (μ-COO){sub 2} double bridges. Magnetic studies indicate antiferromagnetic interactions in 1, ferromagnetic interactions in 2 and 3. Furthermore, compound 3 displays a slow relaxation behavior. Compound 2 exhibits intense characteristic green emission of Tb(III) ions in the solid state, which can be observed by the naked eye under UV light. Interestingly, 2 can selectively sense Pb{sup 2+} and Fe{sup 3+} ions through luminescence enhancement and quenching, respectively. The luminescence quenching mechanisms have been investigated in detail. The study on luminescence Ln-MOFs as a probe for sensing Pb{sup 2+} and Fe{sup 3+} ions is exceedingly rare example. - Graphical abstract: Three Ln-MOFs were successfully synthesized using a 5-(1H-tetrazol-5-yl)isophthalic acid ligand. They displays different magnetic behavior. Especially, the Dy(III) compound slow relaxation behavior. Interestingly, the Tb(III) compound can selectively sense Pb{sup 2+} and Fe{sup 3+} ions through luminescence enhancement and quenching, respectively. - Highlights: • Three Ln-MOFs with tetrazolate dicarboxylate ligand. • Dy(III) compound displays slow relaxation behavior. • The Tb(III) compound shows highly selective luminescence sensing of the Fe{sup 3+} and Pb{sup 2+} ions.

Photoluminescence and cathodoluminescence properties of Sr{sub 2}Gd{sub 8}Si{sub 6}O{sub 26}:RE{sup 3+}(RE{sup 3+}=Tb{sup 3+}or Sm{sup 3+}) phosphors

Energy Technology Data Exchange (ETDEWEB)

Hussain, Sk. Khaja [Department of Electronics and Radio Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Rao, Gattupalli Manikya [Department of Physics, College of Science and Technology, Andhra University, Visakhapatanam, Andhra Pradesh 53003 (India); Raju, G. Seeta Rama; Krishna Bharat, L. [Department of Electronics and Radio Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Subba Rao, P.S.V., E-mail: raopsvs@rediffmail.com [Department of Physics, College of Science and Technology, Andhra University, Visakhapatanam, Andhra Pradesh 53003 (India); Yu, Jae Su, E-mail: jsyu@khu.ac.kr [Department of Electronics and Radio Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

2016-10-15

Trivalent terbium (Tb{sup 3+}) or samarium (Sm{sup 3+}) ions individually activated green and orange emitting Sr{sub 2}Gd{sub 8}Si{sub 6}O{sub 26} (SGSO) phosphors were synthesized by a citrate sol–gel method. The X-ray diffraction patterns of SGSO:Tb{sup 3+} and SGSO:Sm{sup 3+} phosphors exhibited the characteristic diffraction peaks of oxyapatite in a hexagonal lattice structure. The photoluminescence (PL) properties at ultraviolet (UV) or near-UV excitation wavelengths were measured for Tb{sup 3+} or Sm{sup 3+} ions doped SGSO phosphors as a function of its respective concentration. The PL spectra of SGSO:Tb{sup 3+} phosphors revealed the characteristic emission peaks of both Gd{sup 3+} and Tb{sup 3+} ions which are associated with 4f–4f transitions under 274 nm of excitation wavelength. When the concentration of Tb{sup 3+} ions increased over 0.05 mol (5 mol%), the emission intensities of {sup 5}D{sub 3} transitions decreased due to the well-known cross-relaxation process. However, based on the intensities of {sup 5}D{sub 4} transitions, the optimum concentration of Tb{sup 3+} ions was found to be 0.05 mol. Under 404 nm of excitation wavelength, the SGSO:Sm{sup 3+} phosphors exhibited the characteristic orange emission at 600 nm due to the {sup 4}G{sub 5/2}→{sup 6}H{sub 7/2} electronic transition. The optimum concentration of SGSO:Sm{sup 3+} phosphors was found to be 0.02 mol. The decay curves of the optimized SGSO:Tb{sup 3+} and SGSO:Sm{sup 3+} phosphors were well fitted to single exponential functions and their lifetimes were calculated. Furthermore, the optimized phosphor samples showed good thermal stability. Likewise, cathodoluminescence properties were also studied for the optimized samples as a function of filament current and accelerating voltage. The Commission International de I-Eclairage chromaticity coordinates were calculated for the SGSO:Tb{sup 3+} and SGSO:Sm{sup 3+} phosphors.

Hydrothermal synthesis and photoluminescent properties of hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower-like clusters

Science.gov (United States)

Amurisana, Bao.; Zhiqiang, Song.; Haschaolu, O.; Yi, Chen; Tegus, O.

2018-02-01

3D hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower clusters were successfully prepared on glass slide substrate by a simple, economical hydrothermal process with the assistance of disodium ethylenediaminetetraacetic acid (Na2H2L, where L4- = (CH2COO)2N(CH2)2N(CH2COO)24-). In this process, Na2H2L was used as both a chelating agent and a structure-director. The hierarchical flower clusters have an average diameter of 7-12 μm and are composed of well-aligned microrods. The influence of the molar ratio of Na2H2L/Gd3+ and reaction time on the morphology was systematically studied. A possible crystal growth and formation mechanism of hierarchical flower clusters is proposed based on the evolution of morphology as a function of reaction time. The self-assembled GdPO4·H2O:Ln3+ superstructures exhibit strong orange-red (Eu3+, 5D0 → 7F1), green (Tb3+, 5D4 → 7F5) and near ultraviolet emissions (Ce3+, 5d → 7F5/2) under ultraviolet excitation, respectively. This study may provide a new channel for building hierarchically superstructued oxide micro/nanomaterials with optical and new properties.

The effect of core and lanthanide ion dopants in sodium fluoride-based nanocrystals on phagocytic activity of human blood leukocytes

Energy Technology Data Exchange (ETDEWEB)

Sojka, Bartlomiej [Wroclaw University of Science and Technology, Department of Experimental Physics (Poland); Liskova, Aurelia; Kuricova, Miroslava [Slovak Medical University, Medical Faculty, Department of Immunology and Immunotoxicology (Slovakia); Banski, Mateusz; Misiewicz, Jan [Wroclaw University of Science and Technology, Department of Experimental Physics (Poland); Dusinska, Maria [Norwegian Institute for Air Research, Health Effects Laboratory, Department of Environmental Chemistry (Norway); Horvathova, Mira; Ilavska, Silvia; Szabova, Michaela [Slovak Medical University, Medical Faculty, Department of Immunology and Immunotoxicology (Slovakia); Rollerova, Eva [Slovak Medical University, Faculty of Public Health, Department of Toxicology (Slovakia); Podhorodecki, Artur, E-mail: artur.p.podhorodecki@pwr.edu.pl [Wroclaw University of Science and Technology, Department of Experimental Physics (Poland); Tulinska, Jana, E-mail: jana.tulinska@szu.sk [Slovak Medical University, Medical Faculty, Department of Immunology and Immunotoxicology (Slovakia)

2017-02-15

Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of <10-nm NPs was performed according to our variation of patent pending ligand exchange method that resulted in meso-2,3-dimercaptosuccinic acid (DMSA) molecules on their surface. Y-core-based NCs were doped with Eu ions, which enabled them to be excited with UV light wavelengths. Cultures of human peripheral blood (n = 8) were in vitro treated with five different concentrations of eight NPs for 24 h. In summary, neither type of nanoparticles is found toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples.

The effect of core and lanthanide ion dopants in sodium fluoride-based nanocrystals on phagocytic activity of human blood leukocytes

International Nuclear Information System (INIS)

Sojka, Bartlomiej; Liskova, Aurelia; Kuricova, Miroslava; Banski, Mateusz; Misiewicz, Jan; Dusinska, Maria; Horvathova, Mira; Ilavska, Silvia; Szabova, Michaela; Rollerova, Eva; Podhorodecki, Artur; Tulinska, Jana

2017-01-01

Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of <10-nm NPs was performed according to our variation of patent pending ligand exchange method that resulted in meso-2,3-dimercaptosuccinic acid (DMSA) molecules on their surface. Y-core-based NCs were doped with Eu ions, which enabled them to be excited with UV light wavelengths. Cultures of human peripheral blood (n = 8) were in vitro treated with five different concentrations of eight NPs for 24 h. In summary, neither type of nanoparticles is found toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples.

DFTB{sup +} and lanthanides

Energy Technology Data Exchange (ETDEWEB)

Hourahine, B [Department of Physics, SUPA, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Aradi, B; Frauenheim, T, E-mail: benjamin.hourahine@strath.ac.u [BCCMS, Universitaet Bremen, Am Fallturm 1, 28359 Bremen (Germany)

2010-07-01

DFTB{sup +} is a recent general purpose implementation of density-functional based tight binding. One of the early motivators to develop this code was to investigate lanthanide impurities in nitride semiconductors, leading to a series of successful studies into structure and electrical properties of these systems. Here we describe our general framework to treat the physical effects needed for these problematic impurities within a tight-binding formalism, additionally discussing forces and stresses in DFTB. We also present an approach to evaluate the general case of Slater-Koster transforms and all of their derivatives in Cartesian coordinates. These developments are illustrated by simulating isolated Gd impurities in GaN.

Platinum triangles in the Pt/Al framework of the intermetallic REPt6Al3 (RE = Ce-Nd, Sm, Gd, Tb) series

International Nuclear Information System (INIS)

Eustermann, Fabian; Stegemann, Frank; Renner, Konstantin; Janka, Oliver

2017-01-01

The compounds of the REPt 6 Al 3 series (RE = Ce-Nd, Sm, Gd, Tb) were obtained by reaction of the elements via arc-melting. They were characterized by powder and single-crystal X-ray diffraction (NdPt 6 Al 3 : wR = 0.0432, 759 F 2 values, 33 variables) as well as by magnetic susceptibility measurements. The isostructural compounds crystallize with a new structure type in the trigonal crystal system with space group R anti 3c, twelve formula units in the unit cell, and lattice parameters of a = 752-755 and c = 3882-3945 pm. The crystal structure can be described by different slabs stacked along [001]. One layer features Pt 3 triangles, centering the cavities of a flat honeycomb RE layer that are arranged in a..ABCA ' B ' C ' .. sequence. The other layer consists of condensed hexagonal [Pt 6 Al 6 ] prisms, centered by Pt atoms, separating the before mentioned slabs. Magnetic measurements revealed that all rare-earth atoms are in the trivalent oxidation state, however, due to the low lanthanoide content magnetic ordering phenomena were observed only at low temperatures [SmPt 6 Al 3 : T C = 5.0(1) K; GdPt 6 Al 3 : T C = 7.3(1) K; TbPt 6 Al 3 : T N = 3.6(1) K]. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lanthanide ions (III) as sensitizers of melatonin oxidation in reaction mixtures providing reactive species of oxygen and nitrogen

Energy Technology Data Exchange (ETDEWEB)

Kaczmarek, Małgorzata, E-mail: mkaczmar@amu.edu.pl

2015-06-15

Chemiluminescence (CL) of the reactive systems providing strong oxidants (reactive species of oxygen and nitrogen) containing lanthanide ions (III) and melatonin, was studied. Kinetic curves of emission decay and spectral distributions of chemiluminescence were obtained. Analysis of differences in the intensity of chemiluminescence and CL spectra proved that excitation of Tb(III) and Dy(III) ions takes place with the energy transfer from the products of melatonin oxidation: N{sup 1}-acetyl-N{sup 2}-formyl-5-methoxykynuramine (AFMK) and N{sup 1}-acetyl-5-methoxykynuramine (AMK) to the lanthanide ions. In the system Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) a linear correlation was established between the integrated CL intensity and melatonin concent. - Highlights: • Chemiluminescence (CL) of melatonin (Mel) oxidation by reactive species of oxygen and nitrogen. • Tb(III) and Dy(III) ions as sensitizers of a melatonin oxidation process. • New CL method for determination of melatonin in pharmaceutical preparations based on CL of Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) system.

Contribution for study on positron annihilation in tris (dipivaloilmethanates) lanthanides (III)

International Nuclear Information System (INIS)

Ribeiro e Silva, M.E.S.

1988-01-01

Some data on life time of positron and annihilation by Doppler effect in tris (dipivaloilmethanates) lanthanides (III), Ln (dpm) 3 , and Ln = Eu, Gd, Dy, Ho, Er, Tm and Yb are shown. Some results from positronium (Ps) in complexes except Eu (dpm) 3 , chemical aspects and properties of positron and positronium are evaluated. (M.J.C.) [pt

3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

Energy Technology Data Exchange (ETDEWEB)

Sturzbecher-Hoehne, Manuel; Ng Pak Leung, Clara; Daleo, Anthony; Kullgren, Birgitta; Prigent, Anne-Laure; Shuh, David K.; Raymond, Kenneth N.; Abergel, Rebecca J.

2011-07-13

The spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) was investigated for its ability to act as an antennae that sensitizes the emission of Sm{sup III}, Eu{sup III}, and Tb{sup III} in the Visible range (Φ{sub tot} = 0.2 - 7%) and the emission of Pr{sup III}, Nd{sup III}, Sm{sup III}, and Yb{sup III} in the Near Infra-Red range, with decay times varying from 1.78 μs to 805 μs at room temperature. The particular luminescence spectroscopic properties of these lanthanide complexes formed with 3,4,3-LI(1,2-HOPO) were used to characterize their respective solution thermodynamic stabilities as well as those of the corresponding La{sup III}, Gd{sup III}, Dy{sup III}, Ho{sup III}, Er{sup III}, Tm{sup III}, and Lu{sup III} complexes. The remarkably high affinity of 3,4,3-LI(1,2-HOPO) for lanthanide metal ions and the resulting high complex stabilities (pM values ranging from 17.2 for La{sup III} to 23.1 for Yb{sup III}) constitute a necessary but not sufficient criteria to consider this octadentate ligand an optimal candidate for in vivo metal decorporation. The in vivo lanthanide complex stability and decorporation capacity of the ligand were assessed, using the radioactive isotope {sup 152}Eu as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results and demonstrated the great potential of 3,4,3-LI(1,2-HOPO) as a therapeutic metal chelating agent.

Coupling of the 4f Electrons in Lanthanide Molecules

Energy Technology Data Exchange (ETDEWEB)

Kazhdan, Daniel [Univ. of California, Berkeley, CA (United States)

2008-09-01

(C₅Me₅)₂LnOTf where Ln = La, Ce, Sm, Gd, and Yb have been synthesized and these derivatives are good starting materials for the synthesis of (C₅Me₅)₂LnX derivatives. (C₅Me₅)₂Ln(2,2'-bipyridine), where Ln = La, Ce, Sm, and Gd, along with several methylated bipyridine analogues have been synthesized and their magnetic moments have been measured as a function of temperature. In lanthanum, cerium, and gadolinium complexes the bipyridine ligand ligand is unequivocally the radical anion, and the observed magnetic moment is the result of intramolecular coupling of the unpaired electron on the lanthanide fragment with the unpaired electron on the bipyridine along with the intermolecular coupling between radicals. Comparison with the magnetic moments of the known compounds (C₅Me₅)₂Sm(2,2'-bipyridine) and (C₅Me₅)₂Yb(2,2'-bipyridine) leads to an understanding of the role of the Sm^II/Sm^III and Yb^II/Yb^III couple in the magnetic properties of (C₅Me₅)₂Sm(2,2'-bipyridine) and (C₅Me₅)₂Yb(2,2'-bipyridine). In addition, crystal structures of (C₅Me₅)₂Ln(2,2'-bipyridine) and [(C₅Me₅)₂Ln(2,2'-bipyridine)][BPh4](Ln= Ce and Gd), where the lanthanide is unequivocally in the +3 oxidation state, give the crystallographic characteristics of bipyridine as an anion and as a neutral ligand in the same coordination environment, respectively. Substituted bipyridine ligands coordinated to (C₅Me₅)₂Yb are studied to further understand how the magnetic coupling in (C5Me5)2Yb(2,2'-bipyridine) changes with substitutions. In the cases of (C₅Me₅)₂Yb(5,5&apos

Highly Luminescent, Water-Soluble Lanthanide Fluorobenzoates: Syntheses, Structures and Photophysics, Part I: Lanthanide Pentafluorobenzoates.

Science.gov (United States)

Kalyakina, Alena S; Utochnikova, Valentina V; Bushmarinov, Ivan S; Ananyev, Ivan V; Eremenko, Igor L; Volz, Daniel; Rönicke, Franziska; Schepers, Ute; Van Deun, Rik; Trigub, Alexander L; Zubavichus, Yan V; Kuzmina, Natalia P; Bräse, Stefan

2015-12-01

Highly luminescent, photostable, and soluble lanthanide pentafluorobenzoates have been synthesized and thoroughly characterized, with a focus on Eu(III) and Tb(III) complexes as visible emitters and Nd(III) , Er(III) , and Yb(III) complexes as infrared emitters. Investigation of the crystal structures of the complexes in powder form and as single crystals by using X-ray diffraction revealed five different structural types, including monomeric, dimeric, and polymeric. The local structure in different solutions was studied by using X-ray absorption spectroscopy. The photoluminescence quantum yields (PLQYs) of terbium and europium complexes were 39 and 15 %, respectively; the latter value was increased almost twice by using the heterometallic complex [Tb0.5 Eu0.5 (pfb)3 (H2 O)] (Hpfb=pentafluorobenzoic acid). Due to the effectively utilized sensitization strategy (pfb)(-) →Tb→Eu, a pure europium luminescence with a PLQY of 29 % was achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trace diffusion of different nuclear reactions products in polycrystalline tantalum

International Nuclear Information System (INIS)

Beyer, G.J.; Fromm, W.D.; Novgorodov, A.F.

1976-07-01

Measurements of the lattice diffusion coefficients for carrier free isotopes of Hf, Lu, Yb, Tm, Tb, Gd, Eu, Ba, Cs, Y, Sr, Rb and As in polycrystalline tantalum were made over the temperature range 1700 Fsub(As)>Fsub(lanthanides)>Fsub(Sr)>Fsub(Ba)>Fsub(Hf)>Fsub(Rb)>Fsub(Cs). The data indicate, that the Arrhenius relation was obeyed over the entire temperature range. Within the lanthanide-group no differences in the diffusion velocities could be detected, this fact points to a diffusion mechanism of Me 3+ -ions of lanthanides, Me 2+ -ions of earth alkaline elements and Me + -ions of alkaline elements. (author)

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Permanent link: https://www.ias.ac.in/article/fulltext/boms/039/03/0603-0611. Keywords. Predominance area diagram; Kellogg diagram; lanthanide oxychloride; rare-earth mineral processing; thermodynamic properties. Abstract. Isothermal stability field diagrams for Ln−O−Cl systems (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, ...

Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

International Nuclear Information System (INIS)

Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

2011-01-01

Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en) 2 (dien)(η 2 -SbSe 4 )] (Ln=Ce(1a), Nd(1b)), [Ln(en) 2 (dien)(SbSe 4 )] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)(μ-η 1 ,η 2 -SbSe 4 )] ∞ (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)(η 2 -SbSe 4 )] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe 4 ] 3- acts as a monodentate ligand mono-SbSe 4 , a bidentate chelating ligand η 2 -SbSe 4 or a tridentate bridging ligand μ-η 1 ,η 2 -SbSe 4 to the lanthanide(III) center depending on the Ln 3+ ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E g between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: → Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. → The [SbSe 4 ] 3- anion acts as a mono-SbSe 4 , a η 2 -SbSe 4 or a μ-η 1 ,η 2 -SbSe 4 ligand to the Ln 3+ ions. → The soft base ligand [SbSe 4 ] 3- can be controlled to coordinate to the Ln 3+ ions with en+dien and en+trien as co-ligands.

IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

Energy Technology Data Exchange (ETDEWEB)

Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warszawa (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warszawa (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

2015-06-15

This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts.

Science.gov (United States)

Sugimoto, Masumi; Liu, Xin-Ling; Tsunega, Seiji; Nakajima, Erika; Abe, Shunsuke; Nakashima, Takuya; Kawai, Tsuyoshi; Jin, Ren-Hua

2018-05-02

Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu 2 O 3 or Tb 2 O 3 ) nanoparticles (guests) were encapsulated into chiral non-helical SiO 2 nanofibres (host) through calcination of chiral SiO 2 hybrid nanofibres, trapping Eu 3+ (or Tb 3+ ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu 3+ and 545 nm for Tb 3+ . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of alpha-R2MoO6 and R2Mo2O7 (R = rare earths) by using a dielectric chemical bond method.

Science.gov (United States)

Li, Huaiyong; Zhang, Siyuan; Zhou, Shihong; Cao, Xueqiang

2009-09-01

Theoretical researches are performed on the alpha-R2MoO6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore-type R2Mo2O7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10(-6)/K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the alpha-R2MoO6 series; while in the R2Mo2O7 series, the LTEC ranges from 6.80 to 6.61 10(-6)/K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. Copyright 2008 Wiley Periodicals, Inc.

Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, Er) at high pressure

Science.gov (United States)

Turner, Katlyn M.; Tracy, Cameron L.; Mao, Wendy L.; Ewing, Rodney C.

2017-12-01

Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare their response to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant feature that influences their response on compression. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the 〈Sn-O〉 bond in stannate pyrochlore is more covalent than the 〈B-O〉 bonds in titanates, zirconate, and hafnates. In stannates, based on in situ Raman spectroscopy, pyrochlore cation and anion sublattices begin to disorder with the onset of compression, first measured at 0.3 GPa. The extent of sublattice disorder versus pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to an orthorhombic, cotunnite-like structure at ~28 GPa similar transitions have been observed in titanate, zirconate, and hafnate pyrochlores at varying pressures (18-40 GPa) with cation radius ratio. The extent of the phase transition versus pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multi-scale defect-fluorite  +  weberite-type structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlores under similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B 0, of stannates varies linearly and inversely with cation radius ratio from 1 1 1 GPa (Nd2Sn2O7) to 251 GPa (Er2Sn2O7). The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates and suggest that the size of the Ln3+ cation is the primary determining factor of B 0. Additionally, when normalized to r A

Stabilization of actinides and lanthanides in unusually high oxidation states

International Nuclear Information System (INIS)

Eller, P.G.; Penneman, R.A.

1986-01-01

Chemical environments can be chosen which stabilize actinides and lanthanides in unusually high or low oxidation states and in unusual coordination. In many cases, one can rationalize the observed species as resulting from strong charge/size influences provided by specific sites in host lattices (e.g., Tb(IV) in BaTbO 3 or Am(IV) in polytungstate anions). In other cases, the unusual species can be considered from an acid-base viewpoint (e.g., U(III) in AsF 5 /HF solution or Pu(VII) in Li 5 PuO 6 ). In still other cases, an interplay of steric and redox effects can lead to interesting comparisons (e.g., instability of double fluoride salts of Pu(V) and Pu(VI) relative to U, Np, and Am analogues). Generalized ways to rationalize compounds containing actinides and lanthanides in unusual valences (particularly high valences), including the above and numerous other examples, will form the focus of this paper. Recently developed methods for synthesizing high valent f-element fluorides using superoxidizers and superacids at low temperatures will also be described. 65 refs., 8 figs., 9 tabs

A Coordination Chemistry Approach to Fine-Tune the Physicochemical Parameters of Lanthanide Complexes Relevant to Medical Applications.

Science.gov (United States)

Le Fur, Mariane; Molnár, Enikő; Beyler, Maryline; Kálmán, Ferenc K; Fougère, Olivier; Esteban-Gómez, David; Rousseaux, Olivier; Tripier, Raphaël; Tircsó, Gyula; Platas-Iglesias, Carlos

2018-03-02

The geometric features of two pyclen-based ligands possessing identical donor atoms but different site organization have a profound impact in their complexation properties toward lanthanide ions. The ligand containing two acetate groups and a picolinate arm arranged in a symmetrical fashion (L1) forms a Gd 3+ complex being two orders of magnitude less stable than its dissymmetric analogue GdL2. Besides, GdL1 experiences a much faster dissociation following the acid-catalyzed mechanism than GdL2. On the contrary, GdL1 exhibits a lower exchange rate of the coordinated water molecule compared to GdL2. These very different properties are related to different strengths of the Gd-ligand bonds associated to steric effects, which hinder the coordination of a water molecule in GdL2 and the binding of acetate groups in GdL1. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Organometallic complex chemistry of plutonium and selected lanthanides

International Nuclear Information System (INIS)

Seemann, U.

1987-01-01

This study deals with the metallo-organic chemistry of plutonium and also with that of some lanthanides. For plutonium, the conversion of Cs 2 PuCl 6 with four equivalents KCp is investigated. In the series Sm, Gd, Dy and Er, compounds of the type Cp 2 LnX and the base adducts with acetonitrile are analysed. The ligand X passes the series Cl, N 3 , NCS and NCO. Both, the thermal and the vibrational spectroscopic behaviour is investigated. In addition, the effect of a changed ligand sphere on the optical spectrum is discussed. The adduct-free compounds are described by a ternary reaction not yet known from literature. For the first time, force constant calculations are carried out on metallo-organic compounds of lanthanides. With the exception of Cp 2 LnCl compounds, all compouds are presented for the first time in the framework of this study. (orig.) [de

Doping Lanthanide into Perovskite Nanocrystals: Highly Improved and Expanded Optical Properties.

Science.gov (United States)

Pan, Gencai; Bai, Xue; Yang, Dongwen; Chen, Xu; Jing, Pengtao; Qu, Songnan; Zhang, Lijun; Zhou, Donglei; Zhu, Jinyang; Xu, Wen; Dong, Biao; Song, Hongwei

2017-12-13

Cesium lead halide (CsPbX 3 ) perovskite nanocrystals (NCs) have demonstrated extremely excellent optical properties and great application potentials in various optoelectronic devices. However, because of the anion exchange, it is difficult to achieve white-light and multicolor emission for practical applications. Herein, we present the successful doping of various lanthanide ions (Ce 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Er 3+ , and Yb 3+ ) into the lattices of CsPbCl 3 perovskite NCs through a modified hot-injection method. For the lanthanide ions doped perovskite NCs, high photoluminescence quantum yield (QY) and stable and widely tunable multicolor emissions spanning from visible to near-infrared (NIR) regions are successfully obtained. This work indicates that the doped perovskite NCs will inherit most of the unique optical properties of lanthanide ions and deliver them to the perovskite NC host, thus endowing the family of perovskite materials with excellent optical, electric, or magnetic properties.

Surface-Supported Robust 2D Lanthanide-Carboxylate Coordination Networks.

Science.gov (United States)

Urgel, José I; Cirera, Borja; Wang, Yang; Auwärter, Willi; Otero, Roberto; Gallego, José M; Alcamí, Manuel; Klyatskaya, Svetlana; Ruben, Mario; Martín, Fernando; Miranda, Rodolfo; Ecija, David; Barth, Johannes V

2015-12-16

Lanthanide-based metal-organic compounds and architectures are promising systems for sensing, heterogeneous catalysis, photoluminescence, and magnetism. Herein, the fabrication of interfacial 2D lanthanide-carboxylate networks is introduced. This study combines low- and variable-temperature scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) experiments, and density functional theory (DFT) calculations addressing their design and electronic properties. The bonding of ditopic linear linkers to Gd centers on a Cu(111) surface gives rise to extended nanoporous grids, comprising mononuclear nodes featuring eightfold lateral coordination. XPS and DFT elucidate the nature of the bond, indicating ionic characteristics, which is also manifest in appreciable thermal stability. This study introduces a new generation of robust low-dimensional metallosupramolecular systems incorporating the functionalities of the f-block elements. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adducts of some hydrated lanthanide methanesulphonates and N, N - dimethyl - diphenylphosphinamide (DDPA)

International Nuclear Information System (INIS)

Felicissimo, A.M.P.; Oliveira, W. de

1987-01-01

The addition compounds of hydrated lanthanide methanesulphonates (MS) with DDPA is analysed. The compounds with composition Ln (MS) 3 . 2 DDPA (Ln = Ce - Gd) were characterized by elemental analysis, infrared spectra, emission spectrum of the europium compound and molar electrolytic conductance in methanol. The ligand DDPA, was prepared by treating diphenylphosphoryl chloride with dimethylamine in benzene solutions. (M.J.C.) [pt

Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout

Energy Technology Data Exchange (ETDEWEB)

Censi, P., E-mail: censi@unipa.it [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); En.Bio.Tech. - Via Aquileia, 35 90100 Palermo (Italy); Tamburo, E. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); Speziale, S. [Deutsches GeoForschungsZentrum, Telegrafenberg, Potsdam, 14473 (Germany); Zuddas, P. [Institut Genie de l' Environnement et Ecodeveloppement and Departement Sciences de la Terre, UMR 5125, Universite Claude Bernard Lyon 1, 2 rue R. Dubois, Bat GEODE 69622 Villeurbanne Cedex (France); Randazzo, L.A. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); En.Bio.Tech. - Via Aquileia, 35 90100 Palermo (Italy); Institut Genie de l' Environnement et Ecodeveloppement and Departement Sciences de la Terre, UMR 5125, Universite Claude Bernard Lyon 1, 2 rue R. Dubois, Bat GEODE 69622 Villeurbanne Cedex (France); Punturo, R. [Dipartimento di Scienze Geologiche, Universita di Catania, Corso Italia, 55 - 95129 Catania (Italy); Cuttitta, A. [I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); Arico, P. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy)

2011-02-28

Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corresponding to the depletion of elements from Nd to Tb when compared to the variable enrichments of heavy lanthanides, Y, La and Ce. These features and concurrent thermodynamic simulations suggest that phosphate precipitation can occur in lungs due to interactions between volcanic particles and fluids. We propose that patterns of yttrium and lanthanides can represent a viable explanation of some pathology observed in patients after prolonged exposure to atmospheric fallout and are suitable to become a diagnostic parameter of chemical environmental stresses.

Development of a ratiometric time-resolved luminescence sensor for pH based on lanthanide complexes

International Nuclear Information System (INIS)

Liu Mingjing; Ye Zhiqiang; Xin Chenglong; Yuan Jingli

2013-01-01

Highlights: ► A lanthanide complex-based ratiometric luminescent pH sensor was developed. ► The sensor can luminously respond to pH in weakly acidic to neutral media. ► The sensor can be used for monitoring pH with time-resolved luminescence mode. ► The sensor can be also used for monitoring pH with absorbance mode. ► The utility of the sensor for the luminescent cell imaging was demonstrated. - Abstract: Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4′-hydroxy-2,2′:6′,2′′-terpyridine-6,6′′-diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu 3+ and Tb 3+ complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA–Eu 3+ is strongly dependent on the pH values in weakly acidic to neutral media (pK a = 5.8, pH 4.8–7.5), while that of HTTA–Tb 3+ is pH-independent. This unique luminescence response allows the mixture of HTTA–Eu 3+ and HTTA–Tb 3+ (the HTTA–Eu 3+ /Tb 3+ mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb 3+ emission at 540 nm to its Eu 3+ emission at 610 nm, I 540nm /I 610nm , as a signal. Moreover, the UV absorption spectrum changes of the HTTA–Eu 3+ /Tb 3+ mixture at different pHs (pH 4.0–7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A 290nm /A 325nm , as a signal. This feature enables the HTTA–Eu 3+ /Tb 3+ mixture to have an additional function for the pH detection with the absorption spectrometry technique. For loading the complexes into the

TAILORING X-RAY BEAM ENERGY SPECTRUM TO ENHANCE IMAGE QUALITY OF NEW RADIOGRAPHY CONTRAST AGENTS BASED ON GD OR OTHER LANTHANIDES.

Energy Technology Data Exchange (ETDEWEB)

DILMANIAN,F.A.; WEINMANN,H.J.; ZHONG,Z.; BACARIAN,T.; RIGON,L.; BUTTON,T.M.; REN,B.; WU,X.Y.; ZHONG,N.; ATKINS,H.L.

2001-02-17

Gadovist, a 1.0-molar Gd contrast agent from Schering AG, Berlin Germany, in use in clinical MPI in Europe, was evaluated as a radiography contrast agent. In a collaboration with Brookhaven National Laboratory (BNL), Schering AG is developing several such lanthanide-based contrast agents, while BNL evaluates them using different x-my beam energy spectra. These energy spectra include a ''truly'' monochromatic beam (0.2 keV energy bandwidth) from the National Synchrotron Light Source (NSLS), BNL, tuned above the Gd K-edge, and x-ray-tube beams from different kVp settings and beam filtrations. Radiographs of rabbits' kidneys were obtained with Gadovist at the NSLS. Furthermore, a clinical radiography system was used for imaging rabbits' kidneys comparing Gadovist and Conray, an iodinated contrast agent. The study, using 74 kVp and standard Al beam filter for Conray and 66 kVp and an additional 1.5 mm Cu beam filter for Gadovist, produced comparable images for Gadovist and Conray; the injection volumes were the same, while the radiation absorbed dose for Gadovist was slightly smaller. A bent-crystal silicon monochromator operating in the Laue diffraction mode was developed and tested with a conventional x-ray tube beam; it narrows the energy spectrum to about 4 keV around the anode tungsten's Ku line. Preliminary beam-flux results indicate that the method could be implemented in clinical CT if x-ray tubes with {approximately} twice higher output become available.

Slow magnetic relaxation in carbonato-bridged dinuclear lanthanide(III) complexes with 2,3-quinoxalinediolate ligands.

Science.gov (United States)

Vallejo, Julia; Cano, Joan; Castro, Isabel; Julve, Miguel; Lloret, Francesc; Fabelo, Oscar; Cañadillas-Delgado, Laura; Pardo, Emilio

2012-08-11

The coordination chemistry of the 2,3-quinoxalinediolate ligand with different lanthanide(III) ions in basic media in air affords a new family of carbonato-bridged M(2)(III) compounds (M = Pr, Gd and Dy), the Dy(2)(III) analogue exhibiting slow magnetic relaxation behaviour typical of single-molecule magnets.

Multi-quasiparticle excitations in 145Tb

International Nuclear Information System (INIS)

Zheng Yong; Zhou Xiaohong; Zhang Yuhu; Liu Minliang; Guo Yingxiang; Lei Xiangguo; Kusakari, H.; Sugawara, M.

2004-01-01

High-spin states in 145 Tb have been populated using the 118 Sn( 32 S, 1p4n) reaction at a beam energy of 165 MeV. The level scheme of 145 Tb has been established for the first time. The level scheme shows characteristics of spherical or slightly oblate nucleus. Based on the systematic trends of the level structure in the neighboring N=80 isotones, the level structure in 145 Tb below 2 MeV excitation is well explained by coupling an h 11/2 valence proton to the even-even 144 Gd core. Above 2 MeV excitation, most of the yrast levels are interpreted with multi-quasiparticle shell-model configurations. (authors)

Rare-earth organic frameworks involving three types of architecture tuned by the lanthanide contraction effect: hydrothermal syntheses, structures and luminescence.

Science.gov (United States)

Deng, Zhao-Peng; Kang, Wei; Huo, Li-Hua; Zhao, Hui; Gao, Shan

2010-07-21

The first example of rare-earth organic frameworks with 3-aminopyrazine-2-carboxylic acid (Hapca) was synthesized under hydrothermal conditions and characterized by elemental analysis, IR, PL, TG, powder and single-crystal X-ray diffraction. These ten complexes exhibit three different structure types with decreasing lanthanide radii: [La(apca)(3)](n) () for type I, {[Ln(apca)(ox)(H(2)O)(2)].H(2)O}(n) (Ln = Pr (2), Nd (3), ox = oxalate) for type II, and [Ln(2)(apca)(4)(OH)(2)(H(2)O)(2)](n) (Ln = Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Y (10)) for type III. The structure of type I consists of 1D "snowflake" chains along a-axis, which are further interconnected by hydrogen bonds to produce a 3D sra net topology containing infinite (-C-O-La-)(n) rod-shaped SBU. Type II has 2D Ln-apca-ox 4(4)-net, in which a planar udud water tetramers (H(2)O)(4) are formed by coordinated and free water molecules. Type III also comprises of 2D 4(4)-layer network constructed from Ln-apca-OH. The structure diversity is mainly caused by the variation of coordinated ligand and lanthanide contraction effect. Remarkably, the oxalate in type II was in situ synthesized from 3-aminopyrazine-2-carboxylic acid through an oxidation-hydrolysis reaction. The luminescent investigations reveal that complex exhibits strong blue emission and complex exhibits characteristic luminescence of Eu(3+).

The kinetics of lanthanide complexation by EDTA and DTPA in lactate media.

Science.gov (United States)

Nash, K L; Brigham, D; Shehee, T C; Martin, A

2012-12-28

The interaction of trivalent lanthanide and actinide cations with polyaminopolycarboxylic acid complexing agents in lactic acid buffer systems is an important feature of the chemistry of the TALSPEAK process for the separation of trivalent actinides from lanthanides. To improve understanding of metal ion coordination chemistry in this process, the results of an investigation of the kinetics of lanthanide complexation by ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) and diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) in 0.3 M lactic acid/0.3 M ionic strength solution are reported. Progress of the reaction was monitored using the distinctive visible spectral changes attendant to lanthanide complexation by the colorimetric indicator ligand Arsenazo III, which enables the experiment but plays no mechanistic role. Under the conditions of these experiments, the reactions occur in a time regime suitable for study by stopped-flow spectrophotometric techniques. Experiments have been conducted as a function of EDTA/DTPA ligand concentration, total lactic acid concentration, and pH. The equilibrium perturbation reaction proceeds as a first order approach to equilibrium over a wide range of conditions, allowing the simultaneous determination of complex formation and dissociation rate constants. The rate of the complexation reaction has been determined for the entire lanthanide series (except Pm(3+)). The predominant pathway for lanthanide-EDTA and lanthanide-DTPA dissociation is inversely dependent on the total lactate concentration; the complex formation reaction demonstrates a direct dependence on [H(+)]. Unexpectedly, the rate of the complex formation reaction is seen in both ligand systems to be fastest for Gd(3+). Correlation of these results indicates that in 0.3 M lactate solutions the exchange of lanthanide ions between lactate complexes and the polyaminopolycarboxylate govern the process.

Observation of divergent La3+ ion dilute effect in two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RExLa1−x–EBTC (RE3+=Eu3+ or Tb3+; EBTC4−=1,1′-ethynebenzene-3,3′,5,5′-etracarboxylate)

International Nuclear Information System (INIS)

Zhai, Lu; Zhang, Wen-Wei; Ren, Xiao-Ming; Zuo, Jing-Lin

2015-01-01

The lanthanide metal-organic frameworks (MOFs) [Ln 2 (EBTC) 1.5 (CH 3 OH) 4 ]·6H 2 O are isostructural to each other, where EBTC 4− =1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate; Ln 3+ =La 3+ , Eu 3+ and Tb 3+ ; and the corresponding MOF is abbreviated as Ln–EBTC. MOFs Eu–EBTC and Tb–EBTC emit intense red and green luminescence (visible by bare eyes), respectively. The molecular alloys of Eu x La 1−x –EBTC and Tb x La 1−x –EBTC have been successfully prepared by mixing Eu 3+ /Tb 3+ and La 3+ salts with the desired molar ratio in the starting material. Two series of Eu x La 1−x –EBTC and Tb x La 1−x –EBTC molecular alloys are isomorphic to the parent Ln–EBTC MOFs, while exhibit divergent La 3+ ion diluting effect, namely, with increasing the relative amount of La 3+ , the intensity of characteristic emission arising from Tb 3+ ion monotonely increases in Tb x La 1−x –EBTC molecular alloys, whereas that of Eu 3+ ion shows non-monotone decrease in Eu x La 1−x –EBTC molecular alloys. The possible origin is discussed for such a divergent behavior between Eu x La 1−x –EBTC and Tb x La 1−x –EBTC molecular alloys. - Graphical abstract: Two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RE x La 1−x –EBTC (RE 3+ =Eu 3+ or Tb 3+ ; EBTC 4− =1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate) have been successfully prepared by mixing Eu 3+ /Tb 3+ and La 3+ salts with the desired molar ratio in the starting material and showed photoluminescence property with divergent La 3+ ion dilute effect. - Highlights: • 3-D molecular alloys of Eu x La 1−x –EBTC and Tb x La 1−x –EBTC were prepared. • They are isomorphic to the parent Ln–EBTC MOFs. • They show photoluminescence property with divergent La 3+ ion diluting effect. • The possible origin is discussed for such a divergent behavior

Fluorescence Resonance Energy Transfer of the Tb(III)-Nd(III) Binary System in Molten LiCl-KCl Eutectic Salt

Energy Technology Data Exchange (ETDEWEB)

Kim, B. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yun, J. I. [KAIST, Daejeon (Korea, Republic of)

2015-05-15

The lanthanides act as a neutron poison in nuclear reactor with large neutron absorption cross section. For that reason, very low amount of lanthanides is required in the recovered U/TRU ingot product from pyrochemical process. In view of that, the investigation of thermodynamic properties and chemical behaviors of lanthanides in molten chloride salt are necessary to estimate the performance efficiency of pyrochemical process. However, there are uncertainties about knowledge and understanding of basic mechanisms in pyrochemical process, such as chemical speciation and redox behaviors due to the lack of in-situ monitoring methods for high temperature molten salt. The spectroscopic analysis is one of the probable techniques for in-situ qualitative and quantitative analysis. Recently, a few fluorescence spectroscopic measurements on single lanthanide element in molten LiCl-KCl eutectic have been investigated. The fluorescence intensity and the fluorescence lifetime of Tb(III) were decreased as increasing the concentration of Nd(III), demonstrating collisional quenching between donor ions and acceptor ions. The Forster distance (..0) of Tb(III)-Nd(III) binary system in molten LiCl-KCl eutectic was determined in the specific range of .... (0.1-1.0) and .. (1.387-1.496)

Synthesis and luminescence properties of BaTiO3:RE (RE = Gd , Dy ...

Indian Academy of Sciences (India)

thermoluminescence (TL) properties of BaTiO3 samples doped with Gd3+, Dy3+, Tb3+ and Lu3+ were investigated. ... electron microscope using an accelerating voltage of 20 kV. .... doping of 1% mole Gd3+ ion into the BaTiO3 compound.

Development of a ratiometric time-resolved luminescence sensor for pH based on lanthanide complexes.

Science.gov (United States)

Liu, Mingjing; Ye, Zhiqiang; Xin, Chenglong; Yuan, Jingli

2013-01-25

Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4'-hydroxy-2,2':6',2''-terpyridine-6,6''-diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu(3+) and Tb(3+) complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA-Eu(3+) is strongly dependent on the pH values in weakly acidic to neutral media (pK(a) = 5.8, pH 4.8-7.5), while that of HTTA-Tb(3+) is pH-independent. This unique luminescence response allows the mixture of HTTA-Eu(3+) and HTTA-Tb(3+) (the HTTA-Eu(3+)/Tb(3+) mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb(3+) emission at 540 nm to its Eu(3+) emission at 610 nm, I(540 nm)/I(610 nm), as a signal. Moreover, the UV absorption spectrum changes of the HTTA-Eu(3+)/Tb(3+) mixture at different pHs (pH 4.0-7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A(290 nm)/A(325 nm), as a signal. This feature enables the HTTA-Eu(3+)/Tb(3+) mixture to have an additional function for the pH detection with the absorption spectrometry technique. For loading the complexes into the living cells, the acetoxymethyl ester of HTTA was synthesized and used for loading HTTA-Eu(3+) and HTTA-Tb(3+) into the cultured HeLa cells. The luminescence imaging results demonstrated the practical utility of the new sensor for the time-resolved luminescence cell imaging application. Copyright © 2012 Elsevier B.V. All rights reserved.

Platinum triangles in the Pt/Al framework of the intermetallic REPt{sub 6}Al{sub 3} (RE = Ce-Nd, Sm, Gd, Tb) series

Energy Technology Data Exchange (ETDEWEB)

Eustermann, Fabian; Stegemann, Frank; Renner, Konstantin [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Janka, Oliver [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Institut fuer Chemie, Carl von Ossietzky Universitaet Oldenburg (Germany)

2017-12-13

The compounds of the REPt{sub 6}Al{sub 3} series (RE = Ce-Nd, Sm, Gd, Tb) were obtained by reaction of the elements via arc-melting. They were characterized by powder and single-crystal X-ray diffraction (NdPt{sub 6}Al{sub 3}: wR = 0.0432, 759 F{sup 2} values, 33 variables) as well as by magnetic susceptibility measurements. The isostructural compounds crystallize with a new structure type in the trigonal crystal system with space group R anti 3c, twelve formula units in the unit cell, and lattice parameters of a = 752-755 and c = 3882-3945 pm. The crystal structure can be described by different slabs stacked along [001]. One layer features Pt{sub 3} triangles, centering the cavities of a flat honeycomb RE layer that are arranged in a..ABCA{sup '}B{sup '}C{sup '}.. sequence. The other layer consists of condensed hexagonal [Pt{sub 6}Al{sub 6}] prisms, centered by Pt atoms, separating the before mentioned slabs. Magnetic measurements revealed that all rare-earth atoms are in the trivalent oxidation state, however, due to the low lanthanoide content magnetic ordering phenomena were observed only at low temperatures [SmPt{sub 6}Al{sub 3}: T{sub C} = 5.0(1) K; GdPt{sub 6}Al{sub 3}: T{sub C} = 7.3(1) K; TbPt{sub 6}Al{sub 3}: T{sub N} = 3.6(1) K]. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

Energy Technology Data Exchange (ETDEWEB)

Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

2017-10-16

The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Electromotive force measurement of lanthanides in Bi solution

International Nuclear Information System (INIS)

Sheng, Jiawei; Yamana, Hajimu; Moriyama, Hirotake

2000-01-01

The thermodynamic properties of Tb, Dy and Ho dissolved in liquid Bi were determined by the electromotive force (EMF) measurement method. The EMF of the following galvanic cell was measured in the range of 500-800degC over a wide range of solute concentration. Ln(solid)|KCl-LiCl|Ln-Bi (solution) There was observed a linear relationship between the EMFs and the lanthanide (Ln) concentrations in liquid Bi phase at a constant temperature, which agreed with the Nernst's equation. The obtained activity coefficients of lanthanides in liquid Bi solution were almost constant at a fixed temperature condition. Temperature effects on the activity coefficients could be expressed by the following equation: log γ=a+b/T, where a and b are experimental constants which correspond to the entropy and enthalpy of the formation of Ln-Bi compound in the melt, respectively. The thermodynamic quantities obtained were discussed in terms of their systematics along the 4f series. (author)

Organic derivatives of lanthanides containing metal in cycle

International Nuclear Information System (INIS)

Syutkina, O.P.; Rybakova, L.F.; Egorova, E.N.; Sigalov, A.B.; Beletskaya, I.P.

1983-01-01

The reaction of 2.2'-dilithium biphenyl with LnBr 3 (Ln=Pr, Sm, Gd, Ho, Yb here bromium atoms are comparatively easily replaced. Previously unknown organic derivatives of lanthanides containing metal in the cycle are obtained. It is established that a successful extraction of the compound requires reaction conditions, such as the use of ether as a solvent with the followinq addition of TGP, the order of addition of reagents. Compounds are extracted in the form of solvates containing TGP melecules. The complexes prepared are coloured, depending on the metal, beige (Pr, Sm) brown (Gd, Yb) and red-brown (Ho). They dissolve readily in TGP moderately in benzen toluene, CCl 4 . When stored their solubility in benzene and CCl 4 decreases considerably, and after 3-2 days, they are practically insoluhle. The compounds prepared are characterized by the elementary analysis, IR and PMR spectra

Half Life Measurements in 155Gd

International Nuclear Information System (INIS)

Malmskog, S.G.

1966-08-01

In the literature there exists a definite difference for the half life of the 86.5 keV level in Gd depending on whether 155 Eu or 155 Tb sources have been used. Using a good energy resolution electron-electron coincidence spectrometer and a 155 Eu source, a half life of 6.48 ± 0.26 nsec was obtained for the 86.5 keV level. This is in agreement with the values previously measured with 155 Tb sources. The half life of the 105.4 keV level was measured to be 1.12 ± 0.05 nsec

Advancing the scientific basis of trivalent actinide-lanthanide separations

International Nuclear Information System (INIS)

Nash, K.L.

2013-01-01

For advanced fuel cycles designed to support transmutation of transplutonium actinides, several options have been demonstrated for process-scale aqueous separations for U, Np, Pu management and for partitioning of trivalent actinides and fission product lanthanides away from other fission products. The more difficult mutual separation of Am/Cm from La-Tb remains the subject of considerable fundamental and applied research. The chemical separations literature teaches that the most productive alternatives to pursue are those based on ligand donor atoms less electronegative than O, specifically N- and S-containing complexants and chloride ion (Cl - ). These 'soft-donor' atoms have exhibited usable selectivity in their bonding interactions with trivalent actinides relative to lanthanides. In this report, selected features of soft donor reagent design, characterization and application development will be discussed. The roles of thiocyanate, aminopoly-carboxylic acids and lactate in separation processes are detailed. (authors)

Synthesis, structural and luminescence properties of Bi3+ co-doped Y2Sn2O7:Tb nanoparticles

International Nuclear Information System (INIS)

Nigam, S.; Sudarsan, V.; Vatsa, R.K.

2010-01-01

Full text: In recent years, advanced materials derived from Pyrochlore-type oxides (A 2 B 2 O 7 ) have been of extensive scientific and technological interest. Chemical substitution of A or B sites of pyrochlore oxide by rare earth ions is a widely used approach to prepare thermally stable, lanthanide ion doped luminescent materials. Due to the higher symmetry around the A and B sites in the lattice lanthanide ions like Eu 3+ and Tb 3+ when incorporated at the A or B sites give very poor luminescence. This problem can be avoided by incorporating other ions like Bi 3+ in the lattice so that the lattice gets distorted and luminescent intensity from the lanthanide ions increases. The present study deals with the synthesis and characterization of Bi 3+ co-doped Y 2 Sn 2 O 7 :Tb nanoparticles. For the preparation of Tb 3+ and Bi 3+ doped Y 2 Sn 2 O 7 nano-materials, Sn metal, Bi(NO 3 ) 3 , Tb 4 O 7 , Y 2 CO 3 , were used as starting materials. The solution containing Y 3+ , Sn 4+ ,and Bi 3+ -Tb 3+ in ethylene glycol medium was slowly heated up to 120 deg C and then subjected to urea hydrolysis. The obtained precipitate after washing was heated to 700 deg C. As prepared samples are amorphous in nature and 700 deg C heated sample showed well crystalline pyrochlore structure as revealed by the XRD studies. Average particles size is calculated from the width of the X-ray diffraction peaks and found to be ∼ 5 nm. TEM images of the nanoparticles obtained at 700 deg C shows very fine spherical particles having a diameter in the range of 2-5 nm. Luminescence measurements were carried out for as prepared and 700 deg C heated samples of 2.5%Tb doped Y 2 Sn 2 O 7 nanoparticles. Green emission characteristic 5 D 4 7 F 5 transition of Tb 3+ has been observed from as prepared sample but on heating to 700 deg C the emission characteristic of Tb 3+ ions got completely removed . However, there is a significant improvement in Tb 3+ emission from 2.5% Bi 3+ co-doped Y 2 Sn 2 O 7 :Tb 3

Synthesis and characterization of metal soaps of lanthanides (III); Sintese e caracterizacao de saboes metalicos de lantanidios (III)

Energy Technology Data Exchange (ETDEWEB)

Payolla, Filipe Boccato; Ribeiro, Sidney Jose Lima; Massbni, Antonio Carlos [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica; Centro Universitario de Araraquara (UNIARA), Araraquara, SP (Brazil)

2015-07-01

The present study describes synthesis and partial characterization of Eu{sup 3+}, Nd{sup 3+}, Dy{sup 3+}, Tb{sup 3+} and Yb{sup 3+} behenate complexes. The compounds were analyzed using IR-Spectroscopy, TG-DTG, DSC, elemental analysis, XRD, luminescence and SEM. The results show the purity of the compounds. The XRD analysis and the SEM images show the high crystallinity of the complexes. TG-DTG and DSC analyses do not show a liquid crystal behavior, as occurs with other lanthanide metallic soaps. The mass loses until 1000° C show that the compounds lose ligand fragments at specific temperatures. XRD of the residues are compatible with the respective lanthanide oxides. The luminescence analysis shows that the Eu{sup 3+}, Nd{sup 3+} and Tb{sup 3+} complexes presents appreciable emission. The Judd-Ofelt parameters obtained are compatible with the values found in the literature. It was not possible to obtain the complexes in a glass-form because it is difficult to prevent the crystallization of the complexes even using liquid nitrogen. The XDR data indicate that one of the complexes axis has 52 Å of length, agreeing with a structure containing behenate-lanthanide ion-behenate. The structures of the complexes were not fully elucidated and more analyses are necessary. The complexes presented a molar ratio of 3:1 (L:M) and were formulated as Bh{sub 3}Eu, Bh{sub 3}Nd, Bh{sub 3}Dy, Bh{sub 3}Tb e Bh{sub 3}Yb (Bh = behenate anion). (author)

X-ray powder diffraction data on miscellaneous lanthanide compounds

International Nuclear Information System (INIS)

Ferguson, I.F.; Hughes, T.E.

1978-08-01

Recent work on neutron absorbing materials has produced various new X-ray diffraction powder patterns of compounds of the lanthanides. Various inconsistencies in previously published data have been noted, and accurate measurements have been made of the lattice parameters of the rare earth oxides Sm 2 0 3 , Eu 2 0 3 , Gd 2 0 3 which have the monoclinic rare earth type B- structure, as well as Eu0. These data are recorded for reference. The optimum conditions for obtaining X-ray powder diffraction data from europium compounds are also noted. (author)

Synthesis and characterisation of some lanthanide perchlorate complexes of 4-nitrosoantipyrine

International Nuclear Information System (INIS)

Jayasankar, H.; Indrasenan, P.

1988-01-01

Seven lanthanide perchlorate complexes of 4-nitrosoantipyrine (NAP) of the general formula [Ln(NAP) 4 ClO 4 ](ClO 4 ) 2 (where Ln=La, Pr, Nd, Sm, Gd, Dy and Y), have been synthesised and characterised by elemental analyses, molecular weights, conductances, magnetic moments and infrared and electronic spectral data. In these nine-coordinated complexes, all the four NAP molecules are coordinated bidentately and one of the perchlorate groups is coordinated monodentately. (author). 12 refs

Factors Affecting the Efficiency of Excited-States Interactions of Complexes between Some Visible Light-Emitting Lanthanide Ions and Cyclophanes Containing Spirobiindanol Phosphonates

Directory of Open Access Journals (Sweden)

M. S. Attia

2007-01-01

Full Text Available The efficiency of excited-states interactions between lanthanide ions Tb3+ and Eu3+ and some new cyclophanes (I, II, and III has been studied in different media. High luminescence quantum yield values for terbium and europium complexes in DMSO and PMMA were obtained. The photophysical properties of the green and red emissive Tb3+ and Eu3+ complexes have been elucidated, respectively.

Radical-lanthanide ferromagnetic interaction in a T bIII bis-phthalocyaninato complex

Science.gov (United States)

Komijani, Dorsa; Ghirri, Alberto; Bonizzoni, Claudio; Klyatskaya, Svetlana; Moreno-Pineda, Eufemio; Ruben, Mario; Soncini, Alessandro; Affronte, Marco; Hill, Stephen

2018-02-01

Recent studies have highlighted the importance of organic ligands in the field of molecular spintronics, via which delocalized electron-spin density can mediate magnetic coupling to otherwise localized 4 f moments of lanthanide ions, which show tremendous potential for single-molecule device applications. To this end, high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy is employed to study a neutral terbium bis-phthalocyaninato metalorganic complex, [TbPc2 ] 0, with the aim of understanding the magnetic interaction between the Ising-like moment of the lanthanide ion and the unpaired spin density on the coordinating organic radical ligand. The measurements were performed on a previously unknown [TbPc2 ] 0 structural phase crystallizing in the Pnma space group. EPR measurements on powder samples of [TbPc2 ] 0 reveal an anisotropic spectrum, which is attributed to the spin-1/2 radical coupled weakly to the EPR-silent T bIII ion. Extensive double-axis rotation studies on a single crystal reveal two independent spin-1/2 signals with differently oriented (albeit identical) uniaxial g -tensors, in complete agreement with x-ray structural studies that indicate two molecular orientations within the unit cell. The easy-axis nature of the radical EPR spectra thus reflects the coupling to the Ising-like T bIII moment. This is corroborated by studies of the isostructural [YPc2 ] 0 analog (where Y is nonmagnetic yttrium), which gives a completely isotropic radical EPR signal. The experimental results for the terbium complex are well explained on the basis of an effective model that introduces a weak ferromagnetic Heisenberg coupling between an isotropic spin-1/2 and an anisotropic spin-orbital moment, J =6 , that mimics the known, strong easy-axis Tb ⋯P c2 crystal-field interaction.

Study of the luminescence of tris(2-thenoyltrifluoroacetonato)lanthanide(III) complexes covalently linked to 1,10-phenanthroline-functionalized hybrid sol-gel glasses

International Nuclear Information System (INIS)

Lenaerts, Philip; Ryckebosch, Eline; Driesen, Kris; Deun, Rik van; Nockemann, Peter; Goerller-Walrand, Christiane; Binnemans, Koen

2005-01-01

The solubility and uniform distribution of lanthanide complexes in sol-gel glasses can be improved by covalently linking the complexes to the sol-gel matrix. In this study, several lanthanide β-diketonate complexes (Ln=Nd, Sm, Eu, Tb, Er, Yb) were immobilized on a 1,10-phenanthroline functionalized sol-gel glass. For the europium(III) complex, a sol-gel material of diethoxydimethylsilane (DEDMS) with polymer-like properties was derived. For the other lanthanide complexes, the sol-gel glass was prepared by using a matrix of tetramethoxysilane (TMOS) and DEDMS. Both systems were prepared under neutral reaction conditions. High-resolution emission and excitation spectra were recorded. The luminescence lifetimes were measured

Synthesis, structure, luminescent, and magnetic properties of carbonato-bridged Zn(II)2Ln(III)2 complexes [(μ4-CO3)2{Zn(II)L(n)Ln(III)(NO3)}2] (Ln(III) = Gd(III), Tb(III), Dy(III); L(1) = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, L(2) = N,N'-bis(3-ethoxy-2-oxybenzylidene)-1,3-propanediaminato).

Science.gov (United States)

Ehama, Kiyomi; Ohmichi, Yusuke; Sakamoto, Soichiro; Fujinami, Takeshi; Matsumoto, Naohide; Mochida, Naotaka; Ishida, Takayuki; Sunatsuki, Yukinari; Tsuchimoto, Masanobu; Re, Nazzareno

2013-11-04

Carbonato-bridged Zn(II)2Ln(III)2 complexes [(μ4-CO3)2{Zn(II)L(n)Ln(III)(NO3)}2]·solvent were synthesized through atmospheric CO2 fixation reaction of [Zn(II)L(n)(H2O)2]·xH2O, Ln(III)(NO3)3·6H2O, and triethylamine, where Ln(III) = Gd(III), Tb(III), Dy(III); L(1) = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, L(2) = N,N'-bis(3-ethoxy-2-oxybenzylidene)-1,3-propanediaminato. Each Zn(II)2Ln(III)2 structure possessing an inversion center can be described as two di-μ-phenoxo-bridged {Zn(II)L(n)Ln(III)(NO3)} binuclear units bridged by two carbonato CO3(2-) ions. The Zn(II) ion has square pyramidal coordination geometry with N2O2 donor atoms of L(n) and one oxygen atom of a bridging carbonato ion at the axial site. Ln(III) ion is coordinated by nine oxygen atoms consisting of four from the deprotonated Schiff-base L(n), two from a chelating nitrate, and three from two carbonate groups. The temperature-dependent magnetic susceptibilities in the range 1.9-300 K, field-dependent magnetization from 0 to 5 T at 1.9 K, and alternating current magnetic susceptibilities under the direct current bias fields of 0 and 1000 Oe were measured. The magnetic properties of the Zn(II)2Ln(III)2 complexes are analyzed on the basis of the dicarbonato-bridged binuclear Ln(III)-Ln(III) structure, as the Zn(II) ion with d(10) electronic configuration is diamagnetic. ZnGd1 (L(1)) and ZnGd2 (L(2)) show a ferromagnetic Gd(III)-Gd(III) interaction with J(Gd-Gd) = +0.042 and +0.028 cm(-1), respectively, on the basis of the Hamiltonian H = -2J(Gd-Gd)ŜGd1·ŜGd2. The magnetic data of the Zn(II)2Ln(III)2 complexes (Ln(III) = Tb(III), Dy(III)) were analyzed by a spin Hamiltonian including the crystal field effect on the Ln(III) ions and the Ln(III)-Ln(III) magnetic interaction. The Stark splitting of the ground state was so evaluated, and the energy pattern indicates a strong easy axis (Ising type) anisotropy. Luminescence spectra of Zn(II)2Tb(III)2 complexes were observed, while those

Half Life Measurements in {sup 155}Gd

Energy Technology Data Exchange (ETDEWEB)

Malmskog, S G

1966-08-15

In the literature there exists a definite difference for the half life of the 86.5 keV level in Gd depending on whether {sup 155}Eu or {sup 155}Tb sources have been used. Using a good energy resolution electron-electron coincidence spectrometer and a {sup 155}Eu source, a half life of 6.48 {+-} 0.26 nsec was obtained for the 86.5 keV level. This is in agreement with the values previously measured with {sup 155}Tb sources. The half life of the 105.4 keV level was measured to be 1.12 {+-} 0.05 nsec.

Selective Lanthanides Sequestration Based on a Self-Assembled Organo-silica

Energy Technology Data Exchange (ETDEWEB)

Ahmad, M.; Reye, C.; Corriu, R.J. P. [Univ Montpellier, Inst Charles Gerhardt Montpellier, UMR 5253, Chim Mol and Org Solide, F-34095 Montpellier 5 (France); Besson, E. [ICSM Site Marcoule, UMR 5257, Inst Chim Separat Marcoule, F-30207 Bagnols Sur Ceze (France); Van der Lee, Arie [Univ Montpellier, Inst Europeen Membranes, UMR 5635, CNRS, F-34095 Montpellier 5 (France); Besson, E.; Chollet, H. [CEA Valduc, Dept Traitement Mat Nucl, F-21120 Is Sur Tille (France); Guilard, R. [Univ Bourgogne, Inst Chim Mol, CNRS, ICMUB, UMR 5260, F-21078 Dijon (France)

2010-07-01

In this paper, we investigate the cation-exchange properties of a self-assembled hybrid material towards trivalent ions, lanthanides (La{sup 3+}, Eu{sup 3+}, Gd{sup 3+}, Yb{sup 3+}) and Fe{sup 3+}. The bis-zwitterionic lamellar material was prepared by sol-gel process from only 3-aminopropyltriethoxysilane (APTES), succinic anhydride, and ethylenediamine. In ethanol heated under reflux, the exchange ethylenediammonium versus Ln{sup 3+} proved to be complete by complexometry measurements and elemental analyses, one Cl{sup -} ion per one Ln(III) remaining as expected for charge balance. In aqueous solution at 20 degrees C, the material was found to be selective towards lanthanide in spite of the similarity of their ionic radii. The cation uptake depends on the nature of the salt, the difference between two lanthanides reaching up to 20% in some cases. Finally, ion-exchange reaction with FeCl{sub 3} was chosen as a probe to get more information on the material after incorporation of trivalent ions. Based on Moessbauer spectroscopic investigations on the resulting material in conjunction with the XRD analysis of materials containing trivalent ions, a structural model was proposed to describe the incorporation of trivalent ions by exchange reaction within the original zwitterionic material. (authors)

Two series of reactant's ratio-dependent lanthanide organic frameworks derived from nicotinic acid N-oxide and oxalate: synthesis, crystal structures and luminescence properties.

Science.gov (United States)

Yu, Yanyan; Zhang, Lijuan; Zhou, Yunshan; Zuhra, Zareen

2015-03-14

Two series of lanthanide(III)–organic frameworks with the molecular formula [Ln2(NNO)2(OX)2(H2O)4]n (Ln = Eu 1, Tb 2, Sm 3, Dy 4, Gd 5) and [Ln2(NNO)4(OX)(H2O)2]n (Ln = Eu 6, Tb 7, Sm 8, Dy 9, Gd 10) were synthesized successfully under the same hydrothermal conditions with nicotinic N-oxide (HNNO) and oxalic acid (H2OX) as the mixed ligands merely through varying the molar ratio of the reactants. The compounds were characterized by IR, elemental analysis, UV, TG-DTA and powder X-ray diffraction (XRD). X-ray single-crystal diffraction analyses of compounds 1 and 7 selected as representatives and powder XRD analysis of the compounds revealed that both the series of compounds feature three-dimensional (3-D) open frameworks, and crystallize in the triclinic P1 space group while with different unit cell parameters. In compound 1, pairs of Eu(3+) ions and pairs of NNO(−) ligands connect with each other alternately to form a 1-D infinite Eu-NNO double chain, the adjacent 1-D double-chains are then joined together through OX(2−) ligands leading to a 2D layer, the 2-D layers are further ‘pillared’ by OX(2−) ligands resulting in a 3-D framework. In compound 7, the 1-D Tb-NNO infinite chain and its 2-D layer are formed in an almost similar fashion to that in compound 1. The difference between the structures of the two compounds 1 and 7 is that the adjacent 2-D layers in compound 7 are further connected by NNO(−) ligands resulting in a 3-D framework. The photoluminescence properties and energy transfer mechanism of the compounds were studied systematically. The energy level of the lowest triplet states of the HNNO ligand (23148 cm(−1)) was determined based on the phosphorescence spectrum of compound 5 at 77 K. The (5)D0 (Eu(3+)) and (5)D4 (Tb(3+)) emission lifetimes are 0.46 ms, 0.83 ms, 0.69 ms and 0.89 ms and overall quantum yields are 1.03%, 3.29%, 2.58% and 3.78% for the compounds 1, 2, 6 and 7, respectively.

Multicolor Tunable Luminescence Based on Tb3+/Eu3+ Doping through a Facile Hydrothermal Route.

Science.gov (United States)

Wang, Chao; Zhou, Ting; Jiang, Jing; Geng, Huiyuan; Ning, Zhanglei; Lai, Xin; Bi, Jian; Gao, Daojiang

2017-08-09

Ln 3+ -doped fluoride is a far efficient material for realizing multicolor emission, which plays an important part in full-color displays, biolabeling, and MRI. However, studies on the multicolor tuning properties of Ln 3+ -doped fluoride are mainly concentrated on a complicated process using three or more dopants, and the principle of energy transfer mechanism is still unclear. Herein, multicolor tunable emission is successfully obtained only by codoping with Tb 3+ and Eu 3+ ions in β-NaGdF 4 submicrocrystals via a facile hydrothermal route. Our work reveals that various emission colors can be obtained and tuned from red, orange-red, pink, and blue-green to green under single excitation energy via codoping Tb 3+ and Eu 3+ with rationally changed Eu 3+ /Tb 3+ molar ratio due to the energy transfer between Tb 3+ and Eu 3+ ions in the β-NaGdF 4 host matrix. Meanwhile, the energy transfer mechanism in β-NaGdF 4 : x Eu 3+ /y Tb 3+ (x + y = 5 mol %) submicrocrystals is investigated. Our results evidence the potential of the dopants' distribution density as an effective way for analyzing energy transfer and multicolor-controlled mechanism in other rare earth fluoride luminescence materials. Discussions on the multicolor luminescence under a certain dopant concentration based on single host and wavelength excitation are essential toward the goal of the practical applications in the field of light display systems and optoelectronic devices.

Thermal decomposition of lanthanide and actinide tetrafluorides

International Nuclear Information System (INIS)

Gibson, J.K.; Haire, R.G.

1988-01-01

The thermal stabilities of several lanthanide/actinide tetrafluorides have been studied using mass spectrometry to monitor the gaseous decomposition products, and powder X-ray diffraction (XRD) to identify solid products. The tetrafluorides, TbF 4 , CmF 4 , and AmF 4 , have been found to thermally decompose to their respective solid trifluorides with accompanying release of fluorine, while cerium tetrafluoride has been found to be significantly more thermally stable and to congruently sublime as CeF 4 prior to appreciable decomposition. The results of these studies are discussed in relation to other relevant experimental studies and the thermodynamics of the decomposition processes. 9 refs., 3 figs

Separation process for lanthanides based on solvation properties of non ionic surfactants

International Nuclear Information System (INIS)

Draye, M.; Favre-Reguillon, A.; Foos, J.; Cote, G.

2004-01-01

In the present study, cloud-point extraction is used with a lipophilic chelating agent (8-hydroxyquinoline) to extract and separate lanthanum (III) and gadolinium (III) from an aqueous solution. The methodology used is based on the formation of lanthanide (III) organic complexes that are soluble in a micellar phase of non-ionic surfactant. The lanthanide (III) complexes are then extracted into the surfactant-rich phase at a temperature above the cloud-point temperature. The cloud-point temperature, the structure of the lipophilic part of the nonionic surfactant and the chelating agent - metal molar ratio are identified as factors determining the extraction efficiency and selectivity. With Triton X-114, high selectivity and decontamination factor for Gd(III) is observed indicating that micelle mediated extraction involving cloud-point extraction is promising for the specific separation of actinide ions from nuclear waste solution. (authors)

Ternary gallides RE_4Rh_9Ga_5, RE_5Rh_1_2Ga_7 and RE_7Rh_1_8Ga_1_1 (RE=Y, La-Nd, Sm, Gd, Tb). Intergrowth structures with MgCu_2 and CaCu_5 related slabs

International Nuclear Information System (INIS)

Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer; Janka, Oliver

2017-01-01

Fourteen ternary gallides RE_4Rh_9Ga_5, RE_5Rh_1_2Ga_7 and RE_7Rh_1_8Ga_1_1 (RE=Y, La-Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce_4Rh_9Ga_5, Ce_5Rh_1_2Ga_7, Ce_7Rh_1_8Ga_1_1, Nd_5Rh_1_0_._4_4_(_4_)Ga_8_._5_6_(_4_), Nd_4Rh_9Ga_5 and Gd_4Rh_9Ga_5 were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE_2_+_n Rh_3_+_3_n Ga_1_+_2_n structure series in the Parthe intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu_2 (Mg_2Ni_3Si as ternary variant) and CaCu_5 (CeCo_3B_2 as ternary variant). Only the Nd_5Rh_1_0_._4_4_(_4_)Ga_8_._5_6_(_4_) crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y_4Rh_9Ga_5 and Curie-Weiss paramagnetism for Gd_4Rh_9Ga_5 and Tb_4Rh_9Ga_5. Low-temperature data show ferromagnetic ordering at T_C=78.1 (Gd_4Rh_9Ga_5) and 55.8 K (Tb_4Rh_9Ga_5).

A series of novel lanthanide carboxyphosphonates with a 3D framework structure: synthesis, structure, and luminescent and magnetic properties.

Science.gov (United States)

Chen, Kai; Dong, Da-Peng; Sun, Zhen-Gang; Jiao, Cheng-Qi; Li, Chao; Wang, Cheng-Lin; Zhu, Yan-Yu; Zhao, Yan; Zhu, Jiang; Sun, Shou-Hui; Zheng, Ming-Jing; Tian, Hui; Chu, Wei

2012-08-28

By introduction of 1,4-benzenedicarboxylic acid as the second organic ligand, a series of novel lanthanide carboxyphosphonates with a 3D framework structure, namely, [Ln(3)(H(2)L)(HL)(2)(bdc)(2)(H(2)O)]·7H(2)O (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8); H(3)L = H(2)O(3)PCH(2)NC(5)H(9)COOH; H(2)bdc = HOOCC(6)H(4)COOH) have been synthesized under hydrothermal conditions. Compounds are isostructural and feature a 3D framework in which Ln(III) polyhedra are interconnected by bridging {CPO(3)} tetrahedra into 2D inorganic layers parallel to the ab plane. The organic groups of H(2)L(-) are grafted on the two sides of the layer. These layers are further cross-linked by the bdc(2-) ligands from one layer to the Ln atoms from the other into a pillared-layered architecture with one-dimensional channel system along the a axis. The thermal stability of compounds has been investigated. Luminescent properties of compounds , and the magnetic properties of compound have also been studied.

Predicting Efficient Antenna Ligands for Tb(III) Emission

Energy Technology Data Exchange (ETDEWEB)

Samuel, Amanda P.S.; Xu, Jide; Raymond, Kenneth

2008-10-06

A series of highly luminescent Tb(III) complexes of para-substituted 2-hydroxyisophthalamide ligands (5LI-IAM-X) has been prepared (X = H, CH{sub 3}, (C=O)NHCH{sub 3}, SO{sub 3}{sup -}, NO{sub 2}, OCH{sub 3}, F, Cl, Br) to probe the effect of substituting the isophthalamide ring on ligand and Tb(III) emission in order to establish a method for predicting the effects of chromophore modification on Tb(III) luminescence. The energies of the ligand singlet and triplet excited states are found to increase linearly with the {pi}-withdrawing ability of the substituent. The experimental results are supported by time-dependent density functional theory (TD-DFT) calculations performed on model systems, which predict ligand singlet and triplet energies within {approx}5% of the experimental values. The quantum yield ({Phi}) values of the Tb(III) complex increases with the triplet energy of the ligand, which is in part due to the decreased non-radiative deactivation caused by thermal repopulation of the triplet. Together, the experimental and theoretical results serve as a predictive tool that can be used to guide the synthesis of ligands used to sensitize lanthanide luminescence.

Determination of lanthanides in rare earths concentrates by emission optical spectrography

International Nuclear Information System (INIS)

Friedmann, R.; Lordello, A.R.; Abrao, A.

1978-01-01

A spectrochemical method has been developed for the determination of Y, Pr, Sm, Eu, Gd and Dy in purified lanthanum oxide; Y, La, Nd, Sm, Gd and Dy in purified cerium oxide and Y, La, Sm, Eu, Gd and Dy in purified neodymium oxide. The technique consists of an almost total consumption of the sample in a 17 ampere direct current arc. The rare earth oxides are mixed with an equal amount by weight of spectrographic graphite and the electrodes are arced in an argon (80%)-oxygen (20%) atmosphere, inside a specially desingned chamber, to suppress cyanogen bands. The concentration ranges are approximatelly 0.002 - 2%, depending on the matrix and the elements to be analysed. The presicion, accuracy and acceptability of the method are calculated for all elements. The total error values are approximately in the range of 18-48%. The method was developed for quality control of the individual fractions held by pulsed and ion exchange columns in the lanthanide separations, in the Chemical Engineering Centre, Atomic Energy Institute, Sao Paulo [pt

Electron paramagnetic resonance and neutron activation study of lanthanide ions behaviour in fluorite. Application to the geochemical study of Montroc and Burc veins (Tarn)

International Nuclear Information System (INIS)

Meary, Alain

1983-01-01

In order to obtain a better understanding of fluorite deposits, rare earth impurities have been analyzed for a large number of samples taken from cross-sections of several low temperature hydrothermal veins; two types of measurements have been used: Electron Paramagnetic Resonance (EPR) and Neutron Activation Analysis (NAA). This enabled us to measure a 'deficit of spins' relative to the total lanthanide concentration, this deficit reveals that the paramagnetic center observed by EPR is not the only mode of incorporation. For Gd no marked deficit is observed; that is the ratio of spin concentrations to total concentration [Gd 3+ ]/[Gd total ] is close to 1 in all the samples; on the other hand, the ratios [Eu 2+ ]/[Eu total ], [Ce 3- F i - ]/[Ce total ], and [Yb 3+ ]/ [Yb total ] exhibit large variations. The first result suggests that the major part of the lanthanides in the samples is incorporated in the crystal lattice and that clustering of lanthanides ions is not important. Deficit of spins observed for Ce and Nd are probably due to the dissociation of paramagnetic complexes Ce 3+ -F i - and Nd 3+ -F i - ; for Eu, it may be attributed to the oxidized state Eu 3+ . Moreover, the sign and the amplitude of the anomaly exhibited by Eu in the normalized lanthanides spectra may be correlated with the majority valence state of Eu in the crystal: a marked positive anomaly belongs to a deficit of paramagnetic divalent Eu and, inversely, if divalent Eu is the majority valence state, the Eu anomaly appears to be negative. The results obtained for the Montroc vein are consistent with a model involving discontinuous injections of hydrothermal solutions. They may be connected to variations of oxygen fugacity arising from cooling of these solutions and from precipitation of sulfides during fluorite precipitation. (author) [fr

Synthesis, characterization and magnetic properties of novel μ-oxamido heterodinuclear copper(II) - lanthanide(III) complexes

International Nuclear Information System (INIS)

Li, Y.T.; Miao, M.M.; Liao, D.Z.; Jiang, Z.H.; Wang, G.L.

1995-01-01

Six novel μ-oxamido heterobinuclear complexes have been prepared and identified as Cu(oxpn)Ln(L) 2 (ClO 4 ) 3 , where oxpn denotes the N, N'-bis(3-aminopropyl)oxamido dianion, L, 1,10-phenanthroline (phen) and Ln stands for La, Nd, Gd, Tb, Ho, Er. The complexes Cu(oxpn)Gd(oxpn)Gd(phen) 2 (ClO 4 ) 3 were characterized with variable temperature magnetic susceptibility (4-300 K). The exchange integral J (Cu-Gd) was found to be 2.03 cm -1 . The result is commensurate with ferromagnetic interaction between the adjacent metal ions. One plausible mechanism that can cause a ferromagnetic coupling between Gd(III) and Cu(II) is also discussed in terms of spin polarized. (author). 32 refs, 3 figs, 3 tabs

Compensation scheme for online neutron detection using a Gd-covered CdZnTe sensor

Energy Technology Data Exchange (ETDEWEB)

Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr; Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim

2017-06-11

The development of portable and personal neutron dosimeters requires compact and efficient radiation sensors. Gd-157, Gd-155 and Cd-113 nuclei present the highest cross-sections for thermal neutron capture among natural isotopes. In order to allow for the exploitation of the low and medium-energy radiative signature of the said captures, the contribution of gamma background radiation, falling into the same energy range, needs to be cancelled out. This paper introduces a thermal neutron detector based on a twin-dense semiconductor scheme. The neutron-sensitive channel takes the form of a Gd-covered CdZnTe crystal, a high density and effective atomic number detection medium. The background compensation will be carried out by means of an identical CdZnTe sensor with a Tb cover. The setting of a hypothesis test aims at discriminating the signal generated by the signature of thermal neutron captures in Gd from statistical fluctuations over the compensation of both independent channels. The measurement campaign conducted with an integrated single-channel chain and two metal Gd and Tb covers, under Cs-137 and Cf-252 irradiations, provides first quantitative results on gamma-rejection and neutron sensitivity. The described study of concept gives grounds for a portable, online-compatible device, operable in conventional to controlled environments.

Triple energy transfer and color tuning in Tb3+ and Eu3+-coactivated apatite-type gadolinium-containing phosphors

Science.gov (United States)

Guo, Ning; Liang, Qimeng; Li, Shuo; Ouyang, Ruizhuo; Lü, Wei

2017-11-01

A family of apatite-type fluorophosphate phosphors with general formula Sr3Gd(1-m-n)Na(PO4)3F:mTb3+,nEu3+ (SGN:mTb3+,nEu3+) have been synthesized via the high-temperature solid-state reaction method. Triple energy transfer processes from Gd3+ in the host to both Tb3+ and Eu3+, as well as from Tb3+ to Eu3+ have been verified by the photoluminescence spectra. Under the excitation of UV light, both green line from the transitions of Tb3+ and red line origin from the transitions of Eu3+ have been simultaneously observed in a single phase phosphor, which makes a promise for tunable color emissions from yellowish-green through yellow and ultimately to reddish-orange by simply adjusting the Eu3+ content (n) in SGN:0.20Tb3+,nEu3+ phosphors. Additionally, the energy transfer from the Tb3+ to the Eu3+ ions has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism based on the Dexter's theoretical model, and the energy transfer efficiency increases with an increase in Eu3+ concentration.

Using lanthanide chelates and uranyl compounds for diagnostic by fluoroimmunoassays

International Nuclear Information System (INIS)

Santos, Elen G.; Tomiyama, Claudia S.; Kodaira, Claudia A.; Felinto, Maria C.F.C.; Lourenco, Ana V. S.; Brito, Hermi F.

2009-01-01

The importance of the luminescence of lanthanide ions and UO 2 2+ is related to its peculiar characteristics, e.g. long lifetime and line-like emission bands in the visible, which make these ions unique among the species that are known to luminescence. Recent developments in the field of supramolecular chemistry have allowed the design of ligands capable of encapsulating lanthanide ions, thus forming kinetically inert complexes. By introduction of chromophoric groups in these ligands, an intense luminescence of the ion can be obtained via the 'antenna effect', defined as a light conversion process involving distinct absorbing (ligand) and emitting (metal ion) components. In such a process, the quantities that contribute to the luminescence intensity are the efficiency of the absorption, the efficiency of the ligand-metal energy transfer, and the efficiency of the metal luminescence. Encapsulation of lanthanide ions with suitable ligands may therefore give rise to 'molecular devices' capable to emit strong, long-lived luminescence. Besides the intrinsic interest in their excited state properties, compounds of lanthanide ions, in particular of the Eu 3+ and Tb 3+ ions, and now UO 2 2+ are important for their potential use as luminescent labels for biological species in fluoroimmunoassays (FIAs). This is most interesting because fluorimetric labeling represents an alternative method to the use of radioactive labels, which has long been the most common way of quantifying immunoreactions. In this article we report information about luminescent materials, which gave a good signal to quantify biological molecules by TR-FIA, DELFIA , DSLFIA, RIA and FRET. (author)

Triheterometallic Lanthanide Complexes Prepared from Kinetically Inert Lanthanide Building Blocks

DEFF Research Database (Denmark)

Sørensen, Thomas Just; Tropiano, Manuel; Kenwright, Alan M.

2017-01-01

Three molecular structures, each containing three different lanthanide(III) centres, have been prepared by coupling three kinetically inert lanthanide(III) complexes in an Ugi reaction. These 2 kDa molecules were purified by dialysis and characterised by NMR and luminescence techniques. The photo...... and lanthanide(III) centres in these molecules inhibits the efficient sensitisation of europium. We conclude that the intramolecular collisions required for efficient Dexter energy transfer from the sensitiser to the lanthanide(III) centre can be prevented by steric congestion....

Synthesis, characterization and luminescent properties of lanthanide complexes with an unsymmetrical tripodal ligand

Energy Technology Data Exchange (ETDEWEB)

Yan Zhenzhong [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang Yu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)], E-mail: tangyu@lzu.edu.cn; Liu Weisheng; Tan Minyu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2008-09-15

Solid complexes of lanthanide nitrates with a new unsymmetrical tripodal ligand, bis[(2'-benzylaminoformyl)phenoxyl)ethyl](ethyl)amine (L) have been synthesized and characterized by elemental analysis, infrared spectra and molar conductivity measurements. At the same time, the luminescent properties of the Sm(III), Eu(III), Tb(III) and Dy(III) nitrate complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of central metal ions.

Lanthanide oxide and phosphate nanoparticles for thermometry and bimodal imaging =

Science.gov (United States)

Debasu, Mengistie Leweyehu

Nesta tese relatam-se estudos de fotoluminescencia de nanoparticulas de oxidos e fosfatos dopados com ioes trivalentes de lantanideos, respectivamente, nanobastonetes de (Gd,Eu)2O3 e (Gd,Yb,Er)2O3 e nanocristais de (Gd,Yb,Tb)PO4, demonstrando-se tambem aplicacoes destes materiais em revestimentos inteligentes, sensores de temperatura e bioimagem. Estuda-se a transferencia de energia entre os sitios de Eu3+ C2 e S6 dos nanobastonetes Gd2O3. A contribuicao dos mecanismos de transferencia de energia entre sitios para o tempo de subida 5D0(C2) e descartada a favor da relaxacao directa 5D1(C2) 5D0(C2) (i.e., transferencia de energia entre niveis). O maior tempo de decaimento do nivel 5D0(C2) nos nanobastonetes, relativamente ao valor medido para o mesmo material na forma de microcristais, e atribuido, quer a existencia de espacos livres entre nanobastonetes proximos (factor de enchimento ou fraccao volumica), quer a variacao do indice de refraccao efectivo do meio em torno dos ioes Eu3+. A dispersao de nanobastonetes de (Gd,Eu)2O3 em tres resinas epoxi comerciais atraves da cura por UV permite obter nanocompositos epoxi- (Gd,Eu)2O3. Relatam-se estudos cineticos e das propriedades termicas e de fotoluminescencia destes nanocompositos. Estes, preservam as tipicas propriedades de emissao do Eu3+, mostrando o potencial do metodo de cura por UV para obter revistimentos inteligentes e fotoactivos. Considera-se um avanco significativo a realizacao de uma nanoplataforma optica, incorporando aquecedor e termometro e capaz de medir uma ampla gama de temperaturas (300-2000 K) a escala nano, baseada em nanobastonetes de (Gd,Yb,Er)2O3 (termometros) cuja superficie se encontra revestida com nanoparticulas de ouro. A temperature local e calculada usando, quer a distribuicao de Boltzmann (300-1050 K) do racio de intensidades da conversao ascendente 2H11=2!4I15=2/4S3=2!4I15=2, quer a lei de Planck (1200-2000 K) para uma emissao de luz branca atribuida a radiacao do corpo negro

Lanthanide behavior in hypersaline evaporation ponds at Guerrero Negro, Baja California, Mexico - an environment with halophiles

Science.gov (United States)

Choumiline, K.; López-Cortés, A.; Grajeda-Muñoz, M.; Shumilin, E.; Sapozhnikov, D.

2013-12-01

Lanthanides are known, in some cases, to be sensitive to changes in water column or sediment chemistry, a fact that allows them to be used as environmental fingerprints. Nevertheless, the behavior of these elements in hypersaline environments is insufficiently understood, especially in those colonized by bacteria, archaea and eukarya halophiles. Extreme environments like the mentioned exist in the artificially-controlled ponds of the 'Exportadora de Sal' salt-producing enterprise located in Guerrero Negro (Baja California, Mexico). Sediment cores from various ponds were collected, subsampled and measured by ICP-MS and INAA. This allowed differencing the behavior of lanthanides and trace elements under a water column salinity gradient along the evaporation sequence of ponds. Sediment profiles (30 mm long), obtained in Pond 5, dominated by Ca and Mg precipitation and at the same time rich in organic matter due to bacterial mat presence, showed highs and lows of the shale-normalized patterns along different in-core depths. Two groups of elements could be distinguished with similar trends: set A (La, Ce, Pr and Nd) and set B (Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu). The first 'group A' had two prominent peaks at 15 mm and around 22 mm, whereas the 'group B' showed only slight increase at 15 mm and none at 22 mm. Microscopic analyses of prokaryotic cells of a stratified mat in Pond 5 (collected in 2004) showed filamentous bacteria and cyanobacteria with a cell abundance and morphotype richness maxima of prokaryotic cells in a chemocline from 3 mm to 7 mm depth which co-exists nine morphotypes of aerobic and anaerobic prokaryotes Microcoleus chthonoplastes, Leptolyngbya, Cyanothece, Geitlerinema, Spirulina, Chloroflexus, Beggiatoa, Chromatium and Thioploca. Below the 7 mm depth, oxygenic photosynthesis depletes and sulfur reducing compounds increase. The highs of the shale-normalized lanthanide contents of the 'group A' (at 15 mm depth) seem to correlate with the

Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology

Science.gov (United States)

Dezi, Anna; Monachesi, Elenasophie; D'Ignazio, Michela; Scalise, Lorenzo; Montalto, Luigi; Paone, Nicola; Rinaldi, Daniele; Mengucci, Paolo; Loudos, George; Bakas, Athanasios; Michail, Christos; Valais, Ioannis; Fountzoula, Christine; Fountos, George; David, Stratos

2017-11-01

Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE (Absolute efficiency) was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

Photocytotoxic lanthanide complexes

Indian Academy of Sciences (India)

Among many applications of lanthanides, gadolinium complexes are used as magnetic resonance imaging (MRI) contrast agents in clinical radiology and luminescent lanthanides for bioanalysis, imaging and sensing. The chemistry of photoactive lanthanide complexes showing biological applications is of recent origin.

Syntheses, structures, photoluminescence and photocatalysis of 2D layered lanthanide-carboxylates with 2, 2′-dithiodibenzoic acid

Energy Technology Data Exchange (ETDEWEB)

Ding, Ling; Zhong, Jie-Cen; Qiu, Xing-Tai; Sun, Yan-Qiong, E-mail: sunyq@fzu.edu.cn; Chen, Yi-Ping

2017-02-15

Two series of lanthanide-carboxylates, [Ln(2,2′-dtba)(2,2′-Hdtba)(EtOH)]{sub n} (I:Ln=Eu(1a), Dy(1b)) and [Ln(2,2′-dtba)(2,2′-Hdtba)(4,4′-bpy){sub 0.5}]{sub n} (II:Ln=Eu(2a), Dy(2b), Tb(2c) 2,2′-H{sub 2}dtba=2,2′-dithiodibenzoic acid, 4,4′-bpy=4,4′-bipyridine) have been synthesized under hydrothermal conditions. Interestingly, the H{sub 2}dtba organic ligand was generated by in situ S–S reaction of 2-mercaptobenzoic acid. Compounds I and II possess different 2D layered structures based on similar 1D [Ln(2,2′-dtba)]{sup +} chains. Photoluminescence studies reveal that compounds I and II exhibit strong lanthanide characteristic emission bands. Remarkably, Compounds 1b and 2a both exhibit good photocatalytic activity for degradation of Rhodamine-B (Rh-B) under the simulated sunlight irradiation. - Graphical abstract: Two series of lanthanide-carboxylates have been in situ synthesized under hydrothermal conditions. The lanthanide-carboxylates exhibit strong lanthanide characteristic emission bands and good photocatalytic activity for degradation of Rhodamine-B. - Highlights: • 2D layered lanthanide-carboxylates with 2,2′-dithiodibenzoic acid. • In situ S–S reaction of 2-mercaptobenzoic acid under hydrothermal condition. • The Emission spectra of I and II exhibit the characteristic transition of lanthanide ions. • Compounds 1b and 2a exhibit good photocatalytic activity for degradation of Rhodamine-B.

Effects of pressure and magnetic field on transport properties of Y1-xRxCo2 alloys (R=Gd, Tb, Dy, Ho and Er)

International Nuclear Information System (INIS)

Takaesu, Y; Nakama, T; Kinjyo, A; Yonamine, S; Hedo, M; Yagasaki, K; Uchima, K; Uwatoko, Y; Burkov, A T

2010-01-01

Electrical resistivity ρ and thermopower S of Y 1-x R x Co 2 (R=Gd, Tb, Dy, Ho and Er) Laves phase alloy systems were measured at temperatures from 1.5 K to 300 K in magnetic fields up to 15 T and under hydrostatic pressure up to 2 GPa. We show that there is a universal linear relation between the pressure and magnetic field derivatives of the resistivity, dρ/dP and dρ/dB, with gradient, determined by pressure derivative of the critical metamagnetic field of the cobalt 3d electron system. A similar scaling behavior was found for the thermopower dependencies on pressure and alloy composition.

Structural, luminescence and biological studies of trivalent lanthanide complexes with N,N Prime -bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine Schiff base ligand

Energy Technology Data Exchange (ETDEWEB)

Taha, Ziyad A., E-mail: tahaz33@just.edu.jo [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110 (Jordan); Ajlouni, Abdulaziz M. [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110 (Jordan); Al Momani, Waleed [Department of Allied Medical Sciences, Al Balqa Applied University (Jordan)

2012-11-15

New eight lanthanide metal complexes were prepared. These complexes were characterized by elemental analysis, molar conductivity measurements, spectral analysis ({sup 1}H NMR, FT-IR, UV-vis), luminescence and thermal gravimetric analysis. All Ln(III) complexes were 1:1 electrolytes as established by their molar conductivities. The microanalysis and spectroscopic analysis revealed eight-coordinated environments around lanthanide ions with two nitrate ligands behaving in a bidentate manner. The other four positions were found to be occupied with tetradentate L{sub III} ligand. Tb-L{sub III} and Sm-L{sub III} complexes exhibited characteristic luminescence emissions of the central metal ions and this was attributed to efficient energy transfer from the ligand to the metal center. The L{sub III} and Ln-L{sub III} complexes showed antibacterial activity against a number of pathogenic bacteria. - Highlights: Black-Right-Pointing-Pointer Ln(III) ion adopts an eight-coordinate geometry. Black-Right-Pointing-Pointer Luminescence spectra of Sm-L{sub III} and Tb-L{sub III} complexes display the metal centered line emission. Black-Right-Pointing-Pointer Energy transfer process from L{sub III} to Sm in Sm-L{sub III} complex is more efficient than to Tb in Tb-L{sub III} complex. Black-Right-Pointing-Pointer Ln(III) complexes may serve as models for biologically important species.

Fabrication and characterization of pixelated Gd{sub 2}O{sub 2}S:Tb scintillator screens for digital X-ray imaging applications

Energy Technology Data Exchange (ETDEWEB)

Kim, Jongyul, E-mail: kjongyul@kaist.ac.kr [Korea Advanced Institute of Science and Technology, 335 Gwahangno, Daejeon 305-701 (Korea, Republic of); Kyoung Cha, Bo; Hyung Bae, Jun; Lee, Chae-hun; Kim, Hyungtaek; Chang, Sungho; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, 335 Gwahangno, Daejeon 305-701 (Korea, Republic of); Sim, Cheulmuu; Kim, Taejoo [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Daejeon 305-353 (Korea, Republic of)

2011-05-15

X-ray imaging detectors in combination with scintillator screens have been widely used in digital X-ray imaging applications. Gd{sub 2}O{sub 2}S:Tb was used as scintillation material for pixelated scintillator screens based on silicon substrates (wafer) with a micropore array of various dimensions fabricated using the photolithography and deep reactive ion etching (DRIE) process. The relative light output and the modulation transfer function (MTF) of each fabricated scintillator screen were measured by a cooled CCD and compared with those of Lanex screens. The spatial resolution of our scintillator screens was higher but their light outputs were lower than those of Lanex screen probably due to the loss of light at the wall surfaces. Therefore further treatment of the wall surface, such as reflective coating, seems necessary to compensate the light loss.

Direct observation of the discrete energy spectrum of two lanthanide-based single-chain magnets by far-infrared spectroscopy

Science.gov (United States)

Haas, Sabrina; Heintze, Eric; Zapf, Sina; Gorshunov, Boris; Dressel, Martin; Bogani, Lapo

2014-05-01

The far-infrared optical transmission has been studied for two lanthanide-based single-chain magnets DyPhOPh and TbPhOPh in the frequency range between 3 and 80 cm-1. The spectra were acquired at temperatures between 2 and 80 K and magnetic fields up to 6 T. Based on their magnetic field dependence in DyPhOPh two of the observed absorption lines are identified as transitions inside the crystal field split Dy3+ ground multiplet 6H15/2, coupled to the neighboring spins. In TbPhOPh one transition was observed inside the crystal-field-split Tb3+ ground multiplet 7F6. The results allow a spectroscopic investigation of the role of single-ion anisotropy and exchange in Glauber dynamics.

A dynamic model to explain hydration behaviour along the lanthanide series

International Nuclear Information System (INIS)

Duvail, M.; Spezia, R.; Vitorge, P.

2008-01-01

An understanding of the hydration structure of heavy atoms, such as transition metals, lanthanides and actinides, in aqueous solution is of fundamental importance in order to address their solvation properties and chemical reactivity. Herein we present a systematic molecular dynamics study of Ln 3+ hydration in bulk water that can be used as reference for experimental and theoretical research in this and related fields. Our study of hydration structure and dynamics along the entire Ln 3+ series provides a dynamic picture of the CN behavioural change from light (CN=9 predominating) to heavy (CN=8 predominating) lanthanides consistent with the exchange mechanism proposed by Helm, Merbach and co-workers. This scenario is summarized in this work. The hydrated light lanthanides are stable TTP structures containing two kinds of water molecules: six molecules forming the trigonal prism and three in the centre triangle. Towards the middle of the series both ionic radii and polarizabilities decrease, such that first-shell water-water repulsion increases and water-cation attraction decreases. This mainly applies for molecules of the centre triangle of the nine-fold structure. Thus, one of these molecules stay in the second hydration sphere of the lanthanide for longer average times, as one progresses along the lanthanide series. The interchange between predominantly CN=9 and CN=8 is found between Tb and Dy. Therefore, we propose a model that determines the properties governing the change in the first-shell coordination number across the series, confirming the basic hypothesis proposed by Helm and Merbach. We show that it is not a sudden change in behaviour, but rather that it results from a statistical predominance of one first hydration shell structure containing nine water molecules over one containing eight. This is observed progressively across the series. (O.M.)

Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3)

International Nuclear Information System (INIS)

Philippini, V.

2007-12-01

Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An 3+ and Ln 3+ cations. The study of the solubility of double carbonates (AlkLn(CO 3 ) 2 ,xH 2 O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO 3 ) 4 5- whereas the heaviest (Eu and Dy) form Ln(CO 3 ) 3 3- in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO 3 ) 4 5- while Dy to Lu form Ln(CO 3 ) 3 3- . Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO 3 ) 3 3- complex, specially with Cs + . Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

Crystal structure and luminescence of complexes of Eu(III) and Tb(III) with furan-2,5-dicarboxylate

NARCIS (Netherlands)

Akerboom, S.; Fu, W.T.; Lutz, M.; Bouwman, E.

2012-01-01

Four new Ln(III) complexes (Ln = Eu, Tb) with furan-2,5-dicarboxylic acid (H2FDA) as a ligand have been synthesized and characterized in the solid state. Luminescence studies indicate that the compounds exhibit line-like luminescence characteristic of the lanthanide centre upon excitation in the

Tunable paramagnetic relaxation enhancements by [Gd(DPA)3]3- for protein structure analysis

International Nuclear Information System (INIS)

Yagi, Hiromasa; Loscha, Karin V.; Su, Xun-Cheng; Stanton-Cook, Mitchell; Huber, Thomas; Otting, Gottfried

2010-01-01

Paramagnetic relaxation enhancements (PRE) present a powerful source of structural information in nuclear magnetic resonance (NMR) studies of proteins and protein-ligand complexes. In contrast to conventional PRE reagents that are covalently attached to the protein, the complex between gadolinium and three dipicolinic acid (DPA) molecules, [Gd(DPA) 3 ] 3- , can bind to proteins in a non-covalent yet site-specific manner. This offers straightforward access to PREs that can be scaled by using different ratios of [Gd(DPA) 3 ] 3- to protein, allowing quantitative distance measurements for nuclear spins within about 15 A of the Gd 3+ ion. Such data accurately define the metal position relative to the protein, greatly enhancing the interpretation of pseudocontact shifts induced by [Ln(DPA) 3 ] 3- complexes of paramagnetic lanthanide (Ln 3+ ) ions other than gadolinium. As an example we studied the quaternary structure of the homodimeric GCN4 leucine zipper.

Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

Energy Technology Data Exchange (ETDEWEB)

Lapolli, Andre Luis

2006-07-01

Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

Energy Technology Data Exchange (ETDEWEB)

Lapolli, Andre Luis

2006-07-01

Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

Secret lanthanides.

Science.gov (United States)

Sturza, C M

2014-09-15

Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz.

Simulating the synthesis and thermodynamic characteristics of the desolvation of lanthanide borohydride tris-Tetrahydrofuranates

Science.gov (United States)

Gafurov, B. A.; Mirsaidov, I. U.; Nasrulloeva, D. Kh.; Badalov, A.

2013-10-01

Lanthanide borohydride tris-tetrahydrofuranates (Ln(BH4) · 3THF, where THF is tetrahydrofuran and Ln is La, Nd, Sm, Gd, Er, Yb, and Lu) is synthesized via the exchange reaction of lanthanide(III) chloride and sodium borohydride in THF. It is found that synthesis proceeds according to a stepwise mechanism and the product of the reaction (lanthanide borohydride) initiates the process. The two-step character of the desolvation of Ln(BH4)3 · 3THF under steady-state conditions in the temperature range of 300 to 400 K is determined through X-ray phase and chemical analyses, tensiometry, and gas volumetry. It is established that one mole and then two moles of THF are removed from the initial sample at the first and second steps, respectively. Equations for barograms are obtained and the thermodynamic characteristics of desolvation of Ln(BH4)3 · 3THF under study are calculated. Gibbs energy values of the stages of process are determined semi-empirically. The law of its change for the entire series of Ln(BH4)3 · 3THF is determined with the emergence of the tetrad effect.

Structural variability in uranyl-lanthanide hetero-metallic complexes with DOTA and oxalato ligands

International Nuclear Information System (INIS)

Thuery, P.

2009-01-01

Four novel 4f-5f hetero-metallic complexes could be obtained from the reaction of uranyl and lanthanide nitrates with DOTA (H 4 L) under hydrothermal conditions. In all cases, as in the previous examples reported, additional oxalato ligands are formed in situ. Variations in the stoichiometry of the final products and the presence of hydroxo ions in some cases appear to result in a large structural variability. In the two isomorphous complexes [(UO 2 ) 2 Ln 2 (L) 2 (C 2 O 4 )] with Ln = Sm(1) or Eu(2), the lanthanide ion is located in the N 4 O 4 site and is also bound to a carboxylate oxygen atom from a neighbouring unit, to give zigzag chains which are further linked to one another by [(UO 2 ) 2 (C 2 O 4 )] 2+ di-cations, resulting in the formation of a 3D framework. In [(UO 2 ) 4 Gd 2 (L) 2 (C 2 O 4 ) 3 (H 2 O) 6 ].2H 2 O (3), 2D bilayer subunits of the 'double floor' type with uranyl oxalate pillars are assembled into a 3D framework by other, disordered uranyl ions. [(UO 2 ) 2 Gd(L)(C 2 O 4 )(OH)].H 2 O (4) is a 2D assembly in which cationic {[(UO 2 ) 2 (C 2 O 4 )(OH)] + } n chains are linked to one another by the [Gd(L)] - groups. The most notable feature of this compound is the environment of the 4f ion, which is eight-coordinate and twisted square anti-prismatic (TSA'), instead of nine-coordinate mono-capped square anti-prismatic (SA), as generally observed in DOTA complexes of gadolinium(III) and similarly-sized ions. (author)

Lanthanide metal-organic frameworks

International Nuclear Information System (INIS)

Cheng, Peng

2015-01-01

This book contains the following nine chapters: lanthanide metal-organic frameworks: syntheses, properties, and potential applications (Stephen Fordham, Xuan Wang, Mathieu Bosch, Hong-Cai Zhou); 2. chiral lanthanide metal-organic frameworks (Weisheng Liu, Xiaoliang Tang); 3. Porous lanthanide metal-organic frameworks for gas storage and separation (Bin Li, Banglin Chen); 4. Luminescent lanthanide metal-organic frameworks (Xue-Zhi Song, Shu-Yan Song, Hong-Jie Zhang); 5. Metal-organic frameworks based on lanthanide clusters (Lian Chen, Feilong Jiang, Kang Zhou, Mingyan Wu, Maochun Hong); 6. metal-organic frameworks with d-f cyanide bridges: structural diversity, bonding regime, and magnetism (Marilena Ferbinteanu, Fanica Cimpoesu, Stefania Tanase); 7. transition-lanthanide heterometal-organic frameworks: synthesis, structures, and properties (Wei Shi, Ke Liu, Peng Cheng); 8: MOFs of uranium and the actinides (Juan Su, Jiesheng Chen); 9. Nanostructured and/or nanoscale lanthanide metal-organic frameworks (Zhonghao Zhang, Zhiping Zheng).

Lanthanide metal-organic frameworks

Energy Technology Data Exchange (ETDEWEB)

Cheng, Peng (ed.) [Nankai Univ., Tianjin (China). Dept. of Chemistry

2015-03-01

This book contains the following nine chapters: lanthanide metal-organic frameworks: syntheses, properties, and potential applications (Stephen Fordham, Xuan Wang, Mathieu Bosch, Hong-Cai Zhou); 2. chiral lanthanide metal-organic frameworks (Weisheng Liu, Xiaoliang Tang); 3. Porous lanthanide metal-organic frameworks for gas storage and separation (Bin Li, Banglin Chen); 4. Luminescent lanthanide metal-organic frameworks (Xue-Zhi Song, Shu-Yan Song, Hong-Jie Zhang); 5. Metal-organic frameworks based on lanthanide clusters (Lian Chen, Feilong Jiang, Kang Zhou, Mingyan Wu, Maochun Hong); 6. metal-organic frameworks with d-f cyanide bridges: structural diversity, bonding regime, and magnetism (Marilena Ferbinteanu, Fanica Cimpoesu, Stefania Tanase); 7. transition-lanthanide heterometal-organic frameworks: synthesis, structures, and properties (Wei Shi, Ke Liu, Peng Cheng); 8: MOFs of uranium and the actinides (Juan Su, Jiesheng Chen); 9. Nanostructured and/or nanoscale lanthanide metal-organic frameworks (Zhonghao Zhang, Zhiping Zheng).

Perturbing Tandem Energy Transfer in Luminescent Heterobinuclear Lanthanide Coordination Polymer Nanoparticles Enables Real-Time Monitoring of Release of the Anthrax Biomarker from Bacterial Spores.

Science.gov (United States)

Gao, Nan; Zhang, Yunfang; Huang, Pengcheng; Xiang, Zhehao; Wu, Fang-Ying; Mao, Lanqun

2018-06-05

Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

Synthesis, Structure, and Magnetism of Tris(amide) {Ln[N(SiMe3)2]3}1- Complexes of the Non-Traditional +2 Lanthanide Ions.

Science.gov (United States)

Ryan, Austin Jack; Darago, Lucy E; Balasubramini, Sree Ganesh; Chen, Guo P; Ziller, Joseph W; Furche, Filipp; Long, Jeffrey R; Evans, William J

2018-02-28

A new series of Ln2+ complexes has been synthesized that overturns two previous generalizations in rare-earth metal reduction chemistry: that amide ligands do not form isolable complexes of the highly-reducing non-traditional Ln2+ ions and that yttrium is a good model for the late lanthanides in these reductive reactions. Reduction of Ln(NR2)3 (R = SiMe3) complexes in THF under Ar with M = K or Rb in the presence of 2.2.2-cryptand (crypt) forms crystallographically-characterizable [M(crypt)][Ln(NR2)3] complexes not only for the traditional Tm2+ ion and the configurational crossover ions, Nd2+ and Dy2+, but also for the non-traditional Gd2+, Tb2+, Ho2+, and Er2+ ions. Crystallographic data as well as UV-visible, magnetic susceptibility, and density functional theory studies are consistent with the accessibility of 4fn5d1 configurations for Ln2+ ions in this tris(silylamide) ligand environment. The Dy2+ complex, [K(crypt)][Dy(NR2)3], has a higher magnetic moment than previously observed for any monometallic complex: 11.67 µB. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solution chemistry of lanthanide complexes

International Nuclear Information System (INIS)

Brittain, H.G.

1979-01-01

Intermolecular energy transfer from Tb 3+ to Eu 3+ , luminescence intensity measurements, potentiometric titrations, differential absorption spectroscopy, and spectroscopic titrations were all used to study the binding of lanthanide ions by serine and threonine. At low pH (3.0 to 6.0) the complexes are mononuclear and ligand is only weakly bound. In the pH interval of 6.0 to 8.5 stronger interaction takes place between the ligand and the metal (with possible coordination of the undissociated hydroxyl group), and self-association of complexes becomes important. Above pH 8.5, base hydrolysis of the complexes leads to highly associated species in solution and shortly above this pH an insoluble precipitate is formed. It was found that energy could be transferred from Tb 3+ to Eu 3+ more efficiently among complexes prepared from racemic ligands than in complexes made from resolved ligand, but this stereoselectivity was only observed at pH values greater than 6.5 and in solutions having a 1:10 ratio of metal-to-ligand. No stereoselectivity was found in solutions having 1:5 ratios, and this observation was explained by the existence of 1:2 metal-ligand complexes existing in solutions having the higher ratio of metal-to-ligand (only 1:1 complexes are then found at lower ratios of metal-to-ligand). (author)

Anthracene-Based Lanthanide Metal-Organic Frameworks: Synthesis, Structure, Photoluminescence, and Radioluminescence Properties

Directory of Open Access Journals (Sweden)

Stephan R. Mathis

2018-01-01

Full Text Available Four anthracene-based lanthanide metal-organic framework structures (MOFs were synthesized from the combination of the lanthanide ions, Eu3+, Tb3+, Er3+, and Tm3+, with 9,10-anthracenedicarboxylic acid (H2ADC in dimethylformamide (DMF under hydrothermal conditions. The 3-D networks crystalize in the triclinic system with P-1 space group with the following compositions: (i {{[Ln2(ADC3(DMF4·DMF]}n, Ln = Eu (1 and Tb (2} and (ii {{[Ln2(ADC3(DMF2(OH22·2DMF·H2O]}n, Ln = Er (3 and Tm (4}. The metal centers exist in various coordination environments; nine coordinate in (i, while seven and eight coordinate in (ii. The deprotonated ligand, ADC, assumes multiple coordination modes, with its carboxylate functional groups severely twisted away from the plane of the anthracene moiety. The structures show ligand-based photoluminescence, which appears to be significantly quenched when compared with that of the parent H2ADC solid powder. Structure 2 is the least quenched and showed an average photoluminescence lifetime from bi-exponential decay of 0.3 ns. On exposure to ionizing radiation, the structures show radioluminescence spectral features that are consistent with the isolation of the ligand units in its 3-D network. The spectral features vary among the 3-D networks and appear to suggest that the latter undergo significant changes in their molecular and/or electronic structure in the presence of the ionizing radiation.

Electronic and ionic transport in Ce0.8PrxTb0.2-xO2-δ and evaluation of performance as oxygen permeation membranes

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2012-01-01

is significantly enhanced relative to that of a Ce0.9Gd0.1O1.95-δ membrane at high oxygen activities of the permeate gas (aO2 an > 10-15) due to the enhanced electronic conductivity of the Ce0.8PrxTb0.2-xO2-δ compounds. Interference between the ionic and electronic flows has a significant positive effect......The electronic conductivity of Ce0.8PrxTb0.2-xO2-δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 to aO2 ≈ 10-17 at 700- 900 °C by means of Hebb-Wagner polarisation. The electronic conductivity of all the Ce0.8PrxTb0.2-xO2-δ compositions was significantly...... enhanced as compared to that of Ce0.9Gd0.1O1.95-δ, and its value was found to increase with increasing Pr/Tb ratio. The ionic mobility of Ce0.8PrxTb0.2-xO2-δ is similar to that of Ce1- 2δGd2δO2-δ at the same oxygen vacancy concentration. The calculated oxygen flux of a Ce0.8PrxTb0.2-xO2-δ membrane...

Correlation consistent basis sets for lanthanides: The atoms La–Lu

Energy Technology Data Exchange (ETDEWEB)

Lu, Qing; Peterson, Kirk A., E-mail: kipeters@wsu.edu [Department of Chemistry, Washington State University, Pullman, Washington 99164-4630 (United States)

2016-08-07

Using the 3rd-order Douglas-Kroll-Hess (DKH3) Hamiltonian, all-electron correlation consistent basis sets of double-, triple-, and quadruple-zeta quality have been developed for the lanthanide elements La through Lu. Basis sets designed for the recovery of valence correlation (defined here as 4f5s5p5d6s), cc-pVnZ-DK3, and outer-core correlation (valence + 4s4p4d), cc-pwCVnZ-DK3, are reported (n = D, T, and Q). Systematic convergence of both Hartree-Fock and correlation energies towards their respective complete basis set (CBS) limits are observed. Benchmark calculations of the first three ionization potentials (IPs) of La through Lu are reported at the DKH3 coupled cluster singles and doubles with perturbative triples, CCSD(T), level of theory, including effects of correlation down through the 4s electrons. Spin-orbit coupling is treated at the 2-component HF level. After extrapolation to the CBS limit, the average errors with respect to experiment were just 0.52, 1.14, and 4.24 kcal/mol for the 1st, 2nd, and 3rd IPs, respectively, compared to the average experimental uncertainties of 0.03, 1.78, and 2.65 kcal/mol, respectively. The new basis sets are also used in CCSD(T) benchmark calculations of the equilibrium geometries, atomization energies, and heats of formation for Gd{sub 2}, GdF, and GdF{sub 3}. Except for the equilibrium geometry and harmonic frequency of GdF, which are accurately known from experiment, all other calculated quantities represent significant improvements compared to the existing experimental quantities. With estimated uncertainties of about ±3 kcal/mol, the 0 K atomization energies (298 K heats of formation) are calculated to be (all in kcal/mol): 33.2 (160.1) for Gd{sub 2}, 151.7 (−36.6) for GdF, and 447.1 (−295.2) for GdF{sub 3}.

Integrated nanophotonic hubs based on ZnO-Tb(OH3/SiO2 nanocomposites

Directory of Open Access Journals (Sweden)

Lin Yu

2011-01-01

Full Text Available Abstract Optical integration is essential for practical application, but it remains unexplored for nanoscale devices. A newly designed nanocomposite based on ZnO semiconductor nanowires and Tb(OH3/SiO2 core/shell nanospheres has been synthesized and studied. The unique sea urchin-type morphology, bright and sharply visible emission bands of lanthanide, and large aspect ratio of ZnO crystalline nanotips make this novel composite an excellent signal receiver, waveguide, and emitter. The multifunctional composite of ZnO nanotips and Tb(OH3/SiO2 nanoparticles therefore can serve as an integrated nanophotonics hub. Moreover, the composite of ZnO nanotips deposited on a Tb(OH3/SiO2 photonic crystal can act as a directional light fountain, in which the confined radiation from Tb ions inside the photonic crystal can be well guided and escape through the ZnO nanotips. Therefore, the output emission arising from Tb ions is truly directional, and its intensity can be greatly enhanced. With highly enhanced lasing emissions in ZnO-Tb(OH3/SiO2 as well as SnO2-Tb(OH3/SiO2 nanocomposites, we demonstrate that our approach is extremely beneficial for the creation of low threshold and high-power nanolaser.

Measurement of isotopic composition of lanthanides in reprocessing process solutions by high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICP-MS)

International Nuclear Information System (INIS)

Okano, Masanori; Jitsukata, Shu; Kuno, Takehiko; Yamada, Keiji

2011-01-01

Isotopic compositions of fission products in process solutions and wastes in a reprocessing plant are valuable to proceed safety study of the solutions and research/development concerning treatment/disposal of the wastes. The amount of neodymium-148 is a reliable indication to evaluate irradiation history. The isotopic compositions of samarium and gadolinium in high radioactive wastes are referred to as essential data to evaluate environmental impact in geological repositories. However, pretreatment of analysis must be done with complicated chemical separation such as solvent extraction and ion exchange. The actual measurement data of isotopic compositions of lanthanides comparable to the one of actinides in spent fuel reprocessing process has not been obtained enough. Rapid and high sensitive analytical technique based on high-performance liquid chromatography (HPLC) with an inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the measurement of isotopic compositions of lanthanides in spent fuel reprocessing solutions. HPLC/ICP-MS measurement system was customized for a glove-box to be applied to the radioactive solutions. The cation exchange chromatographic columns (Shim-pack IC-C1) and injection valve (20μL) were located inside of the glove-box except the chromatographic pump. The elements of lanthanide group were separated by a gradient program of HPLC with α-hydroxyisobutyric acid. Isotopic compositions of lanthanides in eluate was sequentially analyzed by a quadruple ICP-MS. Optimization of parameter of HPLC and ICP-MS measurement system was examined with standard solutions containing 14 lanthanide elements. The elements of lanthanides were separated by HPLC and detected by ICP-MS within 25 minutes. The detection limits of Nd-146, Sm-147 and Gd-157 were 0.37 μg L -1 , 0.69 μg L -1 and 0.47 μg L -1 , respectively. The analytical precision of the above three isotopes was better than 10% for standard solutions of 100 μg L -1 with

Spectroscopy and energy level location of the trivalent lanthanides in LiYP4O12

International Nuclear Information System (INIS)

Dorenbos, P.; Shalapska, T.; Stryganyuk, G.; Gektin, A.; Voloshinovskii, A.

2011-01-01

The excitation and emission properties of the lanthanides Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Er 3+ , Tm 3+ , and Yb 3+ in LiYP 4 O 12 were studied by vacuum ultra-violet spectroscopy at 10 K. It provides information on the energies of 4f-5d excitation and emission bands. In the case of Er 3+ spin forbidden emission was observed. Charge transfer excitation bands were identified for Eu 3+ , Sm 3+ , Tm 3+ , and Yb 3+ , and in the case of Yb 3+ charge transfer luminescence is observed. All data appear to be consistent with each other and have been used to construct a level scheme showing the location of the energy levels of all trivalent and divalent lanthanides in LiYP 4 O 12 . - Research Highlights: → The spectroscopy of most of the trivalent lanthanides in LiYP 4 O 12 is presented for the first time. → Charge transfer luminescence of Yb3+ is reported. → We demonstrate that the energy of the first 4f-5d transition and the charge transfer band agree with predictive models. → For the first time a scheme with the location of all lanthanide states (divalent and trivalent ) w.r.t. de-valence and conduction band of LIP 4 O 12 is presented.

Lanthanides electrolytic extraction from molten fluoride by alloy formation; Extraction electrochimique des lanthanides des milieux de fluorures fondus par formation d'alliages

Energy Technology Data Exchange (ETDEWEB)

Nourry, Ch

2007-10-15

This work consisted in studying the electrochemical behaviour of some dissolved lanthanides (Gd, Nd, Sm) in LiF-CaF{sub 2} media on inert and reactive cathodes in the 800-920 C temperature range and then to estimate their possible extraction from the melt by reduction on a reactive electrode (Ni, Cu or Ni/Cu). Using electrochemical methods and SEM micrographs, reduction mechanisms and thermodynamic parameters such as standard potential and activity coefficient were determined for the different species in the melt. The Gibbs energies and the reduction mechanisms were determined for LnNi and LnCu compounds. Finally, extractions have been performed on reactive electrodes with very good extraction rate ({>=} 99.7%). (author)

Structural and optical properties of Tb-doped Na-Gd metaphosphate glasses and glass-ceramics

Czech Academy of Sciences Publication Activity Database

Moretti, F.; Vedda, A.; Nikl, Martin; Nitsch, Karel

2009-01-01

Roč. 21, č. 15 (2009), 155103/1-155103/7 ISSN 0953-8984 R&D Projects: GA AV ČR IAA200100626 Institutional research plan: CEZ:AV0Z10100521 Keywords : Na-Gd metaphosphate glass * glass -ceramics * NaGd(PO 3 ) 4 * optical properties * structural properties * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.964, year: 2009

Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids II. Tb3+, Yb3+ and Gd3+ complexes in weakly alkaline conditions

International Nuclear Information System (INIS)

Dong Wenming; Li Weijuan; Tao Zuyi

2002-01-01

The conditional stability constants for tracer concentrations of Tb(III), Yb(III), and Gd(III) with three soil humic acids, three soil fulvic acids and a fulvic acid from weathered coal were determined at pH 9.0-9.1 (these values are similar to those in calcareous soils) in the presence of NaHCO 3 by using the anion exchange method. It was found that 1 : 1 and 1 : 2 complexes were simultaneously formed in the weakly alkaline conditions. The conditional stability constants of these 1 : 1 and 1 : 2 complexes were calculated from the distribution coefficients of rare earth elements at various concentrations of humate or fulvate. The stability constants indicate the very high stability of trivalent Tb 3+ , Yb 3+ and Gd 3+ complexes with humic substances in weakly alkaline conditions. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in the presence of NaHCO 3 by using an anion exchange method were discussed. The conditional stability constants of these 1 : 1 and 1 : 2 complexes were compared in this paper. It was found that stabilities of Tb 3+ 1 : 1 and 1 : 2 complexes with humic acid are greater than the corresponding ones with fulvic acid from the same soil. In addition, the effect of the presence of Ca 2+ as a competitor on the stabilities of 1 : 1 and 1 : 2 complexes of Yb was examined and no pronounced change of stabilities of 1 : 1 complex was found, even though Ca 2+ is in a 10 3 excess to Yb 3+

A series of new Eu/Tb mixed MOFs with tunable color luminescence

Energy Technology Data Exchange (ETDEWEB)

Luo, Ximing; He, Xingxiang; Shi, Jie; Cui, Chenhui; Xu, Yan [College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing (China)

2018-01-17

Two isostructural lanthanide metal-organic frameworks [Ln-MOFs, Ln = Tb (1), Eu (8)] containing oxalic acid ligand with green, red luminescence were solvothermally synthesized. A series of Eu/Tb mixed MOFs (2-7), (C{sub 5}H{sub 6}N){sub 2}[Eu{sub x}Tb{sub 2-x}(H{sub 2}O){sub 2}(C{sub 2}O{sub 4}){sub 4}].2H{sub 2}O, were designed and obtained, which displayed highly tunable luminescence color by adjusting the excitation wavelength. Complexes 1-8 were characterized by IR, elemental analysis, ICP, powder XRD, and TG measurements. The quantum yields of the complexes 1-8 range from 6.89 to 4.15 %, whereas the fluorescence lifetime of 1-8 varies between 1.12 and 0.87 ms. Therefore, with the increase of the molar ratio of Eu, the quantum yields and fluorescence lifetime of the complexes 1-8 gradually decrease. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The new carbodiimide Li_2Gd_2Sr(CN_2)_5 having a crystal structure related to that of Gd_2(CN_2)_3

International Nuclear Information System (INIS)

Unverfehrt, Leonid; Stroebele, Markus; Meyer, H. Juergen

2013-01-01

The new carbodiimide compounds Li_2RE_2Sr(CN_2)_5 (RE = Sm, Gd, Eu, Tb) were prepared by a straight forward solid state metathesis reaction of REF_3, SrF_2, and Li_2(CN_2) at around 600 C. The crystal structure of Li_2Gd_2Sr(CN_2)_5 was solved based on X-ray single-crystal diffraction data. Corresponding Li_2RE_2Sr(CN_2)_5 compounds were analyzed by isotypic indexing of their powder patterns. The crystal structure of Li_2Gd_2Sr(CN_2)_5 can be well related to that of Gd_2(CN_2)_3, because both structures are based on layered structures composed of close packed layers of [N=C=N]"2"- sticks, alternating with layers of metal ions. The crystal structure of Li_2Gd_2Sr(CN_2)_5 can be considered to contain an ABC layer sequence of [N = C=N]"2"- layers with the interlayer voids being occupied by (three) distinct types of cations. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lanthanide ions doped Y2Sn2O7 nano-particles: low temperature synthesis and photoluminescence study

International Nuclear Information System (INIS)

Nigam, Sandeep; Sudarsan, V.; Vatsa, R.K.

2008-01-01

During the past decade, pyrochlore-type oxides (A 2 B 2 O 7 ) have emerged as important host matrices for lanthanide doped luminescent materials due to their higher thermal stability. Up to now, conventional solid-state reaction is the most commonly used synthetic method for preparation, of rare-earth pyrochlore oxides. This synthesis route employs a solid-state reaction of metal-oxide with appropriate rare-earth oxides at high temperature (>1200 deg C) for a long time (several days). However, in present work, Y 2 Sn 2 O 7 nanoparticles co-doped with lanthanide ions Tb 3+ and Ce 3+ were prepared based on the urea hydrolysis of Y 3+ , Sn 4+ , and Ln 3+ in ethylene glycol medium at 150 deg C followed by heating at 500, 700 and 900 deg C

Study of 3-Ethylamino-but-2-enoic acid phenylamide as a new ligand for preconcentration of lanthanides from aqueous media by liquid-liquid extraction prior to ICP-MS analysis.

Science.gov (United States)

Varbanova, Evelina K; Angelov, Plamen A; Stefanova, Violeta M

2016-11-01

In the present work the potential of a new ligand 3-Ethylamino-but-2-enoic acid phenylamide (representing the class of enaminones) for selective preconcentration of lanthanides (La, Ce, Eu, Gd and Er) from aqueous medium is examined. Liquid-liquid extraction parameters, such as pH of the water phase, type and volume of organic solvent, quantity of ligand and reaction time are optimized on model solutions. Recovery of lanthanides by re-extraction with nitric acid makes the LLE procedure compatible with Inductively Coupled Plasma Mass Spectrometry. Spectral and non-spectral interferences are studied. Two isotopes per element are measured (with exception of La) for dynamic evaluation of the potential risk of spectral interference in variable real samples. The selectivity of complex formation reaction towards concomitant alkali and alkali-earth elements eliminates the interferences from sample matrix. Subjecting the standards to the optimized extraction procedure in combination with Re as internal standard is recommended as calibration strategy. The accuracy of developed method is approved by analysis of CRM Bush branches and leaves (NCS DC 73348) and recovery of spiked water and plant samples. The method's limits of detection for both studied objects are in the ranges from 0.2 ((158)Gd) to 3.7 ((139)La) ngl(-1) and 0.02 ((158)Gd) to 0.37((139)La) ngg(-1) for waters and plants respectively. The studied compound is an effective new ligand for preconcentration/separation of lanthanides from aqueous medium by LLE and subsequent determination by ICP-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Intramolecular deactivation processes of electronically excited Lanthanide(III) complexes with organic acids of low molecular weight

Science.gov (United States)

Burek, Katja; Eidner, Sascha; Kuke, Stefanie; Kumke, Michael U.

2018-02-01

The luminescence of Lanthanide(III) complexes with different model ligands was studied under direct as well as sensitized excitation conditions. The research was performed in the context of studies dealing with deep-underground storages for high-level nuclear waste. Here, Lanthanide(III) ions served as natural analogues for Actinide(III) ions and the low-molecular weight organic ligands are present in clay minerals and furthermore, they were employed as proxies for building blocks of humic substances, which are important complexing molecules in the natural environment, e.g., in the far field of a repository site. Time-resolved luminescence spectroscopy was applied for a detailed characterization of Eu(III), Tb(III), Sm(III) and Dy(III) complexes in aqueous solutions. Based on the observed luminescence the ligands were tentatively divided into two groups (A, B). The luminescence of Lanthanide(III) complexes of group A was mainly influenced by an energy transfer to OH-vibrations. Lanthanide(III) complexes of group B showed ligand-related luminescence quenching, which was further investigated. To gain more information on the underlying quenching processes of group A and B ligands, measurements at different temperatures (77 K ≤ T ≤ 353 K) were performed and activation energies were determined based on an Arrhenius analysis. Moreover, the influence of the ionic strength between 0 M ≤ I ≤ 4 M on the Lanthanide(III) luminescence was monitored for different complexes, in order to evaluate the influence of specific conditions encountered in host rocks foreseen as potential repository sites.

Evaluation of optoelectronic response and Raman active modes in Tb{sup 3+} and Eu{sup 3+}-doped gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle systems

Energy Technology Data Exchange (ETDEWEB)

Paul, Nibedita [National Institute of Technology Nagaland, Department of Physics, Dimapur, Nagaland (India); Tezpur University, Department of Physics, Tezpur, Assam (India); Mohanta, D. [Tezpur University, Department of Physics, Tezpur, Assam (India)

2016-09-15

Rare earth oxide (Tb{sup 3+}:Gd{sub 2}O{sub 3} and Eu{sup 3+}:Gd{sub 2}O{sub 3}) nanophosphors are exploited through spectroscopic and microscopic tools with special emphasis on D-F mediated radiative emission and Raman active vibrational modes. Powder X-ray diffraction measurements have revealed cubic crystal structure of the nanosystems and with an average crystallite size varying between ∝3.2 and 4.8 nm. Photoluminescence (PL) spectra of Tb{sup 3+} doped systems signify intense blue-green (∝490 nm) and green (∝544 nm) emissions mediated by {sup 5}D{sub 4} → {sup 7}F{sub 6} and {sup 5}D{sub 4} → {sup 7}F{sub 5} transitional events; respectively. In the PL responses of Eu{sup 3+} doped nanoparticle systems, we also identify magnetically-driven {sup 5}D{sub 0} → {sup 7}F{sub 1} (∝591 nm) and electrically driven {sup 5}D{sub 0} → {sup 7}F{sub 2} (∝619 nm) radiative features which seem to improve with increasing doping level. However, the magnitude of Judd-Ofelt (J-O) intensity parameters (Ω {sub 2,} {sub 4}), is significantly lowered for the high doping cases. Raman spectra of the undoped and RE doped systems exhibited several A{sub g} and F{sub g} modes in the range of Raman shift ∝100-600 cm{sup -1}. In the Raman spectra, the peaks located at ∝355 cm{sup -1} are assigned to the mixed mode of F{sub g} + A{sub g}, the line width of which was found to increase with RE doping. Moreover, owing to the enhanced defect concentration in the doped systems than its undoped counterpart, we anticipate a faster phonon relaxation and consequently, a suppression of phonon lifetime in the former case. (orig.)

The Lanthanide Contraction Revisited

Energy Technology Data Exchange (ETDEWEB)

Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

2007-04-19

A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

Highly Luminescent Lanthanide Complexes of 1 Hydroxy-2-pyridinones

Energy Technology Data Exchange (ETDEWEB)

University of California, Berkeley; Lawrence National Laboratory; Raymond, Kenneth; Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodriguez, Ingrid; Raymond, Kenneth N.

2007-11-01

The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ({Phi}{sub tot}{sup Eu} {approx} 21.5%) with high stability (pEu {approx} 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2.

Science.gov (United States)

Minasian, Stefan G; Batista, Enrique R; Booth, Corwin H; Clark, David L; Keith, Jason M; Kozimor, Stosh A; Lukens, Wayne W; Martin, Richard L; Shuh, David K; Stieber, S Chantal E; Tylisczcak, Tolek; Wen, Xiao-Dong

2017-12-13

Understanding the nature of covalent (band-like) vs ionic (atomic-like) electrons in metal oxides continues to be at the forefront of research in the physical sciences. In particular, the development of a coherent and quantitative model of bonding and electronic structure for the lanthanide dioxides, LnO 2 (Ln = Ce, Pr, and Tb), has remained a considerable challenge for both experiment and theory. Herein, relative changes in mixing between the O 2p orbitals and the Ln 4f and 5d orbitals in LnO 2 are evaluated quantitatively using O K-edge X-ray absorption spectroscopy (XAS) obtained with a scanning transmission X-ray microscope and density functional theory (DFT) calculations. For each LnO 2 , the results reveal significant amounts of Ln 5d and O 2p mixing in the orbitals of t 2g (σ-bonding) and e g (π-bonding) symmetry. The remarkable agreement between experiment and theory also shows that significant mixing with the O 2p orbitals occurs in a band derived from the 4f orbitals of a 2u symmetry (σ-bonding) for each compound. However, a large increase in orbital mixing is observed for PrO 2 that is ascribed to a unique interaction derived from the 4f orbitals of t 1u symmetry (σ- and π-bonding). O K-edge XAS and DFT results are compared with complementary L 3 -edge and M 5,4 -edge XAS measurements and configuration interaction calculations, which shows that each spectroscopic approach provides evidence for ground state O 2p and Ln 4f orbital mixing despite inducing very different core-hole potentials in the final state.

Fabrication and photoluminescence properties of color-tunable light emitting lanthanide doped GdVO4 hierarchitectures

International Nuclear Information System (INIS)

Amurisana, Bao; Bao, Lihong; Bao, Liang; Tegus, O.

2017-01-01

The flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ , Tm 3+ ) hierarchitectures have been successfully synthesized on a glass slide substrate through a one-pot hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na 2 H 2 L, where L 4- =(CH 2 COO) 2 N(CH 2 ) 2 N(CH 2 COO) 2 4- ). A high density and ordered flower-like GdVO 4 :Ln 3+ hierarchitectures grew epitaxially on glass substrate. The as-prepared flower-like architectures with the size about 6 μm are constructed by the numerous radially oriented single-crystalline nanorods with the width from 20 nm to 200 nm and the length from 500 nm to 3 μm. The morphologies, the thickness, and the density of as-grown flower clusters can be readily tuned by tailoring the growth time and Na 2 H 2 L/Gd 3+ molar ratio. The possible formation mechanism of flower-like GdVO 4 :Ln 3+ hierarchitectures is discussed on the basis of the results from the controlled experiments under hydrothermal conditions. Because of an energy transfer from vanadate groups to dopants, the flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ) superstructures showed strong characteristic dominant emissions of the Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ions at 617 nm ( 5 D 0 → 7 F 2 , strong red), 575 nm ( 4 F 9/2 → 6 H 13/2 , yellow), 604 nm ( 4 G 5/2 → 6 H 7/2 , orange-red) and 476 nm ( 1 G 4 – 3 H 6 , blue) under ultraviolet excitation, respectively.Further, the emission color of the product can also be tuned by selecting the dopant Ln 3+ with characteristic emissions and varying the concentration ratio of co-doping activators. This approach could be extended to the fabrication of hierarchical structures for other oxide micro/nanomaterials, and may provide a general way to achieve multicolor-tunable emission for many applications.

Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In

International Nuclear Information System (INIS)

Lapolli, Andre Luis

2006-01-01

Systematic behavior of magnetic hyperfine field (B hf ) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B hf were carried out at the rare earth atom and in sites using the nuclear probes 140 Ce and 11 '1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from 140 Ce probe as well as at in sites obtained from 111 Cd probe for each series of compounds were extrapolated to zero Kelvin B hf (T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B hf comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B hf (T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with 111 Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the 111 Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

Sparkle/PM3 for the modeling of europium(III), gadolinium(III), and terbium(III) complexes

International Nuclear Information System (INIS)

Freire, Ricardo O.; Rocha, Gerd B.; Simas, Alfredo M.

2009-01-01

The Sparkle/PM3 model is extended to europium(III), gadolinium(III), and terbium(III) complexes. The validation procedure was carried out using only high quality crystallographic structures, for a total of ninety-six Eu(III) complexes, seventy Gd(III) complexes, and forty-two Tb(III) complexes. The Sparkle/PM3 unsigned mean error, for all interatomic distances between the trivalent lanthanide ion and the ligand atoms of the first sphere of coordination, is: 0.080 A for Eu(III); 0.063 A for Gd(III); and 0.070 A for Tb(III). These figures are similar to the Sparkle/AM1 ones of 0.082 A, 0.061 A, and 0.068 A respectively, indicating they are all comparable parameterizations. Moreover, their accuracy is similar to what can be obtained by present-day ab initio effective core potential full geometry optimization calculations on such lanthanide complexes. Finally, we report a preliminary attempt to show that Sparkle/PM3 geometry predictions are reliable. For one of the Eu(III) complexes, BAFZEO, we created hundreds of different input geometries by randomly varying the distances and angles of the ligands to the central Eu(III) ion, which were all subsequently fully optimized. A significant trend was unveiled, indicating that more accurate local minima geometries cluster at lower total energies, thus reinforcing the validity of sparkle model calculations. (author)

Fluorescent detection of dipicolinic acid as a biomarker of bacterial spores using lanthanide-chelated gold nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Donmez, Mert [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey); Yilmaz, M. Deniz, E-mail: deniz.yilmaz@gidatarim.edu.tr [Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, Konya 42080 (Turkey); Kilbas, Benan, E-mail: benankilbas@duzce.edu.tr [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey)

2017-02-15

Highlights: • The nanosensors based on gold nanoparticles functionalized with lanthanide complexes were synthesized. • The nanosensors selectively and sensitively detected DPA, a biomarker of bacterial spores. • Ratiometric sensing of DPA by a ternary complex was achieved by ligand displacement strategy. - Abstract: Gold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were used for the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TFNB ternary complex quenched the initial emission of the complex at 615 nm and increased the TFNB emission at 450 nm when excited at 350 nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy.

Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

International Nuclear Information System (INIS)

Majeed, Abdul; Khan, Muhammad Azhar; Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F.; Murtaza, Ghulam; Akhtar, Majid Niaz; Shakir, Imran; Warsi, Muhammad Farooq

2016-01-01

Rare-earth (RE=La 3+ , Nd 3+ , Gd 3+ , Tb 3+ , Dy 3+ ) doped Ba 2 NiCoRE x Fe 28−x O 46 (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm −1. Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b VI ). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La 3+ , Nd 3+ , Gd 3+ , Tb 3+ , Dy 3+ ) doped Ba 2 NiCoRE x Fe 28−x O 46 (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba 2 NiCoRE x Fe 28−x O 46 ferrites. • The crystallite size was found in the range 7–19 nm. • The rare-earth incorporation enhanced the coercivity (664–926 Oe). �

Recovery of lanthanides

International Nuclear Information System (INIS)

Tilley, G.L.; Doyle, W.E.

1990-01-01

This paper discusses a method for recovering a lanthanide and thorium from a material containing a fluorine compound and the lanthanide and thorium. It comprises a. obtaining the material from a roasted, acid-leached bastnasite ore; b. forming a mixture of the material with at least about ten weight percent of silica; c. contacting the mixture with sulfuric acid; d. heating the mixture and sulfuric acid to a temperature of at least about 150 degrees C for at least about 3 hours to cause most of the fluorine to be released as a volatile material containing silicon and fluorine; e. contacting the reacted mixture with an aqueous medium consisting essentially of water to solubilize the lanthanide and thorium while leaving an insoluble residue; and f. separating the aqueous solution of the lanthanide and thorium from the insoluble residue

Growth of multiferroic Gd1-xYxMnO3 single crystals by optical floating zone technique

International Nuclear Information System (INIS)

Sarguna, R.M.; Ganesamoorthy, S.; Sridharan, V.; Subramanian, N.

2014-01-01

Rare earth manganites RMnO 3 with distorted perovskite structure are excellent multiferroic materials. The discovery of magnetic spin driven ferroelectricity in orthorhombic manganites (TbMnO 3 ) has sparked a surge in research into understanding the fundamental mechanism of multiferroic behavior. These systems fall under the category of type-2 multiferroics, the change of spatially modulated magnetic moment from sinusoidal to cycloidal gives rise to electric polarization. The magnetic structure depends upon the Mn-O-Mn bond angle. GdMnO 3 shows multiferroic properties only in the presence of applied magnetic field. When a magnetic field is applied along the b-axis, GdMnO 3 enters a ferroelectric state with an electric polarisation along the c-axis. By altering the Mn-O-Mn angle it is expected that GdMnO 3 will show multiferroic property even in the absence of magnetic field like TbMnO 3 . To alter the Mn-O-Mn bond angle GdMnO 3 was substituted with Y having lower ionic radius at Gd site. The effect of Y doping at the rare-earth site in GdMnO 3 investigated on polycrystalline samples of Gd 1-x Y x MnO 3 demonstrated a magneto-electric coupling in x=0.1-0.4. Single crystals are expected to give much amplified signal in respect of ferroelectric and magnetic properties. In this work we have grown Y substituted Gd 1-x Y x MnO 3 (x = 0.2, 0.3 and 0.4) by optical floating zone technique under different gas atmosphere. Growth rate of 1-2 mm/h yielded crack free crystals. Quality of the crystals was checked using Laue diffraction. Effect of growth rate and atmosphere pressure will be presented in this talk. (author)

Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples

International Nuclear Information System (INIS)

Thorson, Megan K.; Ung, Phuc; Leaver, Franklin M.; Corbin, Teresa S.; Tuck, Kellie L.; Graham, Bim; Barrios, Amy M.

2015-01-01

A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. - Highlights: • Lanthanide–azide based sulfide sensors were synthesized and characterized. • The probes have excitation and emission profiles compatible with sulfide-contaminated samples from the petrochemical industry. • A terbium-based probe was used to measure the sulfide concentration in oil refinery wastewater. • A europium-based probe had compatibility with partially refined crude oil samples.

Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples

Energy Technology Data Exchange (ETDEWEB)

Thorson, Megan K. [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States); Ung, Phuc [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Leaver, Franklin M. [Water & Energy Systems Technology, Inc., Kaysville, UT 84037 (United States); Corbin, Teresa S. [Quality Services Laboratory, Tesoro Refining and Marketing, Salt Lake City, UT 84103 (United States); Tuck, Kellie L., E-mail: kellie.tuck@monash.edu [School of Chemistry, Monash University, Victoria 3800 (Australia); Graham, Bim, E-mail: bim.graham@monash.edu [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Barrios, Amy M., E-mail: amy.barrios@utah.edu [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States)

2015-10-08

A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. - Highlights: • Lanthanide–azide based sulfide sensors were synthesized and characterized. • The probes have excitation and emission profiles compatible with sulfide-contaminated samples from the petrochemical industry. • A terbium-based probe was used to measure the sulfide concentration in oil refinery wastewater. • A europium-based probe had compatibility with partially refined crude oil samples.

Strong exchange and magnetic blocking in N₂³⁻-radical-bridged lanthanide complexes.

Science.gov (United States)

Rinehart, Jeffrey D; Fang, Ming; Evans, William J; Long, Jeffrey R

2011-05-22

Single-molecule magnets approach the ultimate size limit for spin-based devices. These complexes can retain spin information over long periods of time at low temperature, suggesting possible applications in high-density information storage, quantum computing and spintronics. Notably, the success of most such applications hinges upon raising the inherent molecular spin-inversion barrier. Although recent advances have shown the viability of lanthanide-containing complexes in generating large barriers, weak or non-existent magnetic exchange coupling allows fast relaxation pathways that mitigate the full potential of these species. Here, we show that the diffuse spin of an N(2)(3-) radical bridge can lead to exceptionally strong magnetic exchange in dinuclear Ln(III) (Ln = Gd, Dy) complexes. The Gd(III) congener exhibits the strongest magnetic coupling yet observed for that ion, while incorporation of the high-anisotropy Dy(III) ion gives rise to a molecule with a record magnetic blocking temperature of 8.3 K at a sweep rate of 0.08 T s(-1).

Observation of divergent La{sup 3+} ion dilute effect in two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RE{sub x}La{sub 1−x}–EBTC (RE{sup 3+}=Eu{sup 3+} or Tb{sup 3+}; EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-etracarboxylate)

Energy Technology Data Exchange (ETDEWEB)

Zhai, Lu [State Key Laboratory of Materials-Oriented Chemical Engineering and College of Science, Nanjing Tech University, Nanjing 210009 (China); State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Wen-Wei, E-mail: wwzhang@nju.edu.cn [State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Ren, Xiao-Ming, E-mail: xmren@njtech.edu.cn [State Key Laboratory of Materials-Oriented Chemical Engineering and College of Science, Nanjing Tech University, Nanjing 210009 (China); Zuo, Jing-Lin [State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2015-10-15

The lanthanide metal-organic frameworks (MOFs) [Ln{sub 2}(EBTC){sub 1.5}(CH{sub 3}OH){sub 4}]·6H{sub 2}O are isostructural to each other, where EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate; Ln{sup 3+}=La{sup 3+}, Eu{sup 3+} and Tb{sup 3+}; and the corresponding MOF is abbreviated as Ln–EBTC. MOFs Eu–EBTC and Tb–EBTC emit intense red and green luminescence (visible by bare eyes), respectively. The molecular alloys of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC have been successfully prepared by mixing Eu{sup 3+}/Tb{sup 3+} and La{sup 3+} salts with the desired molar ratio in the starting material. Two series of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC molecular alloys are isomorphic to the parent Ln–EBTC MOFs, while exhibit divergent La{sup 3+} ion diluting effect, namely, with increasing the relative amount of La{sup 3+}, the intensity of characteristic emission arising from Tb{sup 3+} ion monotonely increases in Tb{sub x}La{sub 1−x}–EBTC molecular alloys, whereas that of Eu{sup 3+} ion shows non-monotone decrease in Eu{sub x}La{sub 1−x}–EBTC molecular alloys. The possible origin is discussed for such a divergent behavior between Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC molecular alloys. - Graphical abstract: Two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RE{sub x}La{sub 1−x}–EBTC (RE{sup 3+}=Eu{sup 3+} or Tb{sup 3+}; EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate) have been successfully prepared by mixing Eu{sup 3+}/Tb{sup 3+} and La{sup 3+} salts with the desired molar ratio in the starting material and showed photoluminescence property with divergent La{sup 3+} ion dilute effect. - Highlights: • 3-D molecular alloys of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC were prepared. • They are isomorphic to the parent Ln–EBTC MOFs. • They show photoluminescence property with divergent La

Luminescence and energy transfer properties of Eu3+ and Gd3+ in ZrO2

International Nuclear Information System (INIS)

Villabona-Leal, E.G.; Diaz-Torres, L.A.; Desirena, H.; Rodríguez-López, J.L.; Pérez, Elías; Meza, Octavio

2014-01-01

Red luminescence emission in ZrO2:Gd 3+ –Eu 3+ nanocrystal under 250 nm radiation excitation is achieved. These materials exhibit a tetragonal phase that is retained by the presence of lanthanide ions. Thus, a study of the optical properties as a function of the dopant concentration was been carried out without the deleterious effects of having segregation of other crystalline phases. We analyze the emission and lifetime curves as a function of dopant concentration through a rate equation simulation, finding an excellent fitting. As results, the nonradiative and radiative relaxation constants, as well as a quantitative estimation of the energy transfer processes among Eu 3+ , Gd 3+ and O 2− ions are reported for the first time. The proposed model can be extended (or applicable) to explain the fluorescence dynamics in other nanomaterials doped with Eu 3+ and Gd 3+ under UV excitation. -- Highlights: • ZrO 2 nanocrystal exhibits a tetragonal phase in the presence of Eu and Gd dopants. • Emission and lifetimes as a function of dopant concentration were analyzed by rate equation model. • Quantitative estimation of the energy transfer processes among Eu 3+ , Gd 3+ and O 2− ions are reported

First principle studies of electronic and magnetic properties of Lanthanide-Gold (RAu) binary intermetallics

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Sardar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Rashid, E-mail: rashmad@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Jalali-Asadabadi, S. [Department of Physics, Faculty of Sciences, University of Isfahan (UI), Hezar Gerib Avenue, Isfahan 81746-73441 (Iran, Islamic Republic of); Ali, Zahid [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Physics, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Iftikhar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Vice Chancellor, Abbott Abad University of Science and Technology, Abbott Abad (Pakistan)

2017-01-15

In this article we explore the electronic and magnetic properties of RAu intermetallics (R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) for the first time. These properties are calculated by using GGA, GGA+U and hybrid density functional theory (HF) approaches. Our calculations show that HF provides superior results, consistent to the experimentally reported data. The chemical bonding between rare-earth and gold atoms within these compounds are explained on the basis of spin dependent electronic clouds in different planes, which shows predominantly ionic and metallic nature between Au and R atoms. The Cohesive energies of RAu compounds show direct relation with the melting points. Spin-dependent electronic band structure demonstrates that all these compounds are metallic in nature. The magnetic studies show that HoAu and LuAu are stable in non-magnetic structure, PrAu is stable in ferromagnetic phase and CeAu, NdAu, SmAu, GdAu, TbAu, DyAu, ErAu, TmAu, YbAu are anti-ferromagnetic materials.

Thermodynamics of complexation of lanthanides with 2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl) pyridine

Energy Technology Data Exchange (ETDEWEB)

Rawat, N.; Bhattacharyya, A.; Tomar, B.S. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Radiochemistry Div.; Ghosh, S.K.; Gadly, T. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Bioorganic Div.

2011-07-01

Solvent extraction studies on separation of trivalent actinides from lanthanides using 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl) pyridines have shown promising results with respect to separation factor and efficiency in acidic medium. In order to understand their complexation behavior, the stability constant (log {beta}) of trivalent lanthanides (La, Nd, Eu, Tb, Ho, Tm, Lu) with 2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl)pyridine (ethyl-BTP) have been determined in methanol medium (ionic strength 0.01 M) using spectrophotometric titrations. The stoichiometry of the complexes is found to vary with the ionic size of lanthanide ion. The variation in log {beta} across the lanthanide series is attributed to variation in solvation characteristics of the metal ion. Comparison of log {beta} for Ln(III)-ethyl-BTP complexes with other alkyl derivatives showed increase in the stability with increasing length of the alkyl group due to hydrophobic interaction. In the case of Eu(III), the speciation was also corroborated by time resolved fluorescence spectroscopy. The thermodynamic parameters ({delta} G, {delta} H, {delta} S) for complexation of Eu(III) with ethyl-BTP, were determined by microcalorimetry, which revealed strong metal ion-ligand interaction with the reactions driven mainly by enthalpy. (orig.)

Proton configurations and pairing correlations at the N=80 superdeformed shell closure: Study of 145Tb

International Nuclear Information System (INIS)

Mullins, S.M.; Schmeing, N.C.; Flibotte, S.; Hackman, G.; Rodriguez, J.L.; Waddington, J.C.; Yao, L.; Andrews, H.R.; Galindo-Uribarri, A.; Janzen, V.P.; Radford, D.C.; Ward, D.; DeGraaf, J.; Drake, T.E.; Pilotte, S.; Paul, E.S.

1994-01-01

A superdeformed band has been observed in the N=80 nucleus 145 Tb which was produced with the reactions 112 Sn( 37 Cl,2p2n) and 118 Sn( 31 P,4n) at bombarding energies of 187 and 160 MeV, respectively. Since superdeformed bands also exist in the three lighter N=80 isotones 142 Sm, 143 Eu, and 144 Gd, it is now possible to understand the valence-proton configurations of these bands in a systematic way. The T (2) dynamic moment of inertia in 145 Tb shows no evidence for the N = 6 quasiproton crossing that is observed in 144 Gd. Comparison with cranked Woods-Saxon and total Routhian surface calculations suggests that the proton configuration in 145 Tb is 6 1 direct-product[404] 9/2 + 2 in which the quasiproton crossing is blocked. Furthermore, like 143 Eu and 142 Sm, there is no evidence in the T (2) for the N=6 quasineutron crossing predicted by the calculations. This may indicate that static neutron pairing correlations are quenched at the N=80 superdeformed shell closure

From Antenna to Assay: Lessons Learned in Lanthanide Luminescence

Energy Technology Data Exchange (ETDEWEB)

Moore, Evan; Samuel, Amanda; Raymond, Kenneth

2008-09-25

Ligand-sensitized luminescent lanthanide(III) complexes are of considerable current interest due to their unique photophysical properties (micro- to millisecond lifetimes, characteristic and narrow emission bands, and large Stokes shifts), which make them well suited to serve as labels in fluorescence-based bioassays. The long-lived Ln(III) emission can be temporally resolved from scattered light and background fluorescence, resulting in vastly enhanced measurement sensitivity. One of the challenges in this field is the design of sensitizing ligands that provide highly emissive Ln(III) complexes that also possess sufficient stability and aqueous solubility required for practical applications. In this account we give an overview of some of the general properties of the trivalent lanthanides and follow with a summary of advances made in our laboratory in the development of highly luminescent Tb(III) and Eu(III) complexes for applications in biotechnology. A focus of our research has been the optimization of these compounds as potential commercial agents for use in Homogeneous Time Resolved Fluorescence (HTRF) technology, the requirements and current use of which will be briefly discussed. Our approach involves developing high-stability octadentate Tb(III) and Eu(III) complexes that rely on all-oxygen donor atoms as well as using multi-chromophore chelates to increase molar absorptivity compared to earlier examples that utilize a single pendant antenna chromophore. We have found that ligands based on 2-hydroxyisophthalamide (IAM) provide exceptionally emissive Tb(III) complexes with quantum yield values up to ca. 60%. Solution thermodynamic studies have indicated that these complexes are stable at the nanomolar concentrations required for commercial assays. Through synthetic modification of the IAM-chromophore, in conjunction with time-dependent density functional theory (TD-DFT) calculations, we have developed a method to predict absorption and emission properties of

Positive/negative liquid secondary ion mass spectrometry of Ln-EDTA (1:1) complexes. Formation of molecular ion adducts with neutral species of the matrix or Ln-EDTA

International Nuclear Information System (INIS)

Plaziak, A.S.; Lis, S.; Elbanowski, M.

1992-01-01

The mass spectra of 1:1 complexes of EDTA with lanthanide cations (Ln=Sm, Eu, Gd, Tb or Dy) upon positive/negative LSIMS are presented. In glycerol used as a matrix, adduct-ions such as [M+H] + , [M+H+nGly] + , [2M+H] + , [2M+H+Gly] + (positive LSIMS) or [M-H] - , [M-H+nGly] - , [2M-H] - , [2M-H+Gly] - (negative LSIMS), where n=1-3, are formed. Reactions leading to the formation of adduct-ions are suggested. (authors)

Laser-induced time-resolved spectrofluorometry and thermal lensing: applications in the nuclear industry

International Nuclear Information System (INIS)

Decambox, P.; Delorme, N.; Mauchien, P.; Moulin, C.

1989-01-01

Sensitive spectroscopic methods for the determination of actinides and lanthanides in various media are required in the nuclear industry. Laser-Induced Time-Resolved Spectrofluorometry (LITRS) for several actinides and lanthanides at very low levels and thermal lensing (TL) for oxidation state characterization allow these determinations. The set-up of LITRS is presented. Spectra, limit of detections and lifetimes obtained for U, Cm, Am, Eu, Gd, Tb, Dy, Ce, Sm, Tm are shown. Detection limit as low as 5.10 -12 M can be achieved. Examples of matrices encountered for the determination of uranium are given as well as comparison with mass spectrometry and alpha counting. The set-up of TL and performances obtained on plutonium as well as future developments are presented

Interplay of spin-dependent delocalization and magnetic anisotropy in the ground and excited states of [Gd2@C78]- and [Gd2@C80]-

Science.gov (United States)

Mansikkamäki, Akseli; Popov, Alexey A.; Deng, Qingming; Iwahara, Naoya; Chibotaru, Liviu F.

2017-09-01

The magnetic properties and electronic structure of the ground and excited states of two recently characterized endohedral metallo-fullerenes, [Gd2@C78]- (1) and [Gd2@C80]- (2), have been studied by theoretical methods. The systems can be considered as [Gd2]5+ dimers encapsulated in a fullerene cage with the fifteen unpaired electrons ferromagnetically coupled into an S = 15/2 high-spin configuration in the ground state. The microscopic mechanisms governing the Gd-Gd interactions leading to the ferromagnetic ground state are examined by a combination of density functional and ab initio calculations and the full energy spectrum of the ground and lowest excited states is constructed by means of ab initio model Hamiltonians. The ground state is characterized by strong electron delocalization bordering on a σ type one-electron covalent bond and minor zero-field splitting (ZFS) that is successfully described as a second order spin-orbit coupling effect. We have shown that the observed ferromagnetic interaction originates from Hund's rule coupling and not from the conventional double exchange mechanism. The calculated ZFS parameters of 1 and 2 in their optimized geometries are in qualitative agreement with experimental EPR results. The higher excited states display less electron delocalization, but at the same time they possess unquenched first-order angular momentum. This leads to strong spin-orbit coupling and highly anisotropic energy spectrum. The analysis of the excited states presented here constitutes the first detailed study of the effects of spin-dependent delocalization in the presence of first order orbital angular momentum and the obtained results can be applied to other mixed valence lanthanide systems.

Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3); Mise en evidence d'un changement de stoechiometrie du complexe carbonate limite au sein de la serie des lanthanides(3)

Energy Technology Data Exchange (ETDEWEB)

Philippini, V

2007-12-15

Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An{sup 3+} and Ln{sup 3+} cations. The study of the solubility of double carbonates (AlkLn(CO{sub 3}){sub 2},xH{sub 2}O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO{sub 3}){sub 4}{sup 5-} whereas the heaviest (Eu and Dy) form Ln(CO{sub 3}){sub 3}{sup 3-} in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO{sub 3}){sub 4}{sup 5-} while Dy to Lu form Ln(CO{sub 3}){sub 3}{sup 3-}. Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO{sub 3}){sub 3}{sup 3-} complex, specially with Cs{sup +}. Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

Luminescence and Magnetic Properties of Tb(III) Complexes with TETA and Synergistic Effect by 1,10-Phenanthroline

International Nuclear Information System (INIS)

Kang, Jung Youl; Shin, Su jeong; Kim, Jae Kwan; Park, Kyoung Chan

2016-01-01

Two Tb(III) complexes, [Tb(TETA)]− and [Tb(TETA)(phen)]− (TETA = 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetate and phen=1,10-phenanthroline), were synthesized and their luminescence ("5D_4 → "7F_=_0_-_6 transitions) and magnetic properties were examined. The photoluminescence (PL) quantum yield of [Tb(TETA)(phen)]− (Q = 0.47) was significantly higher than that of [Tb(TETA)]− (Q = 0.006). The dramatic increase (78 x) in green luminescence was attributed to intramolecular energy transfer from phen to Tb(III). The energy transfer rate according to Dexter theory was found to be approximately 1011s−1. The temperature dependence of the molar susceptibilities confirmed that the two complexes behave as paramagnets obeying the Curie–Weiss law. In addition, the field-dependent magnetization of the two complexes measured in the −70 to + 70 kOe range at T=1.8K fitted well with the Brillouin function with the following values: g _e_f_f=1.5, μ B =9.27×10−21 emu, and J=6. These results provide new insights into the development of lanthanide metal complexes with tetraaza

Luminescence and Magnetic Properties of Tb(III) Complexes with TETA and Synergistic Effect by 1,10-Phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Kang, Jung Youl; Shin, Su jeong; Kim, Jae Kwan; Park, Kyoung Chan [Hanbat National University, Daejeon (Korea, Republic of)

2016-09-15

Two Tb(III) complexes, [Tb(TETA)]− and [Tb(TETA)(phen)]− (TETA = 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetate and phen=1,10-phenanthroline), were synthesized and their luminescence ({sup 5}D{sub 4} → {sup 7}F{sub =0-6} transitions) and magnetic properties were examined. The photoluminescence (PL) quantum yield of [Tb(TETA)(phen)]− (Q = 0.47) was significantly higher than that of [Tb(TETA)]− (Q = 0.006). The dramatic increase (78 x) in green luminescence was attributed to intramolecular energy transfer from phen to Tb(III). The energy transfer rate according to Dexter theory was found to be approximately 1011s−1. The temperature dependence of the molar susceptibilities confirmed that the two complexes behave as paramagnets obeying the Curie–Weiss law. In addition, the field-dependent magnetization of the two complexes measured in the −70 to + 70 kOe range at T=1.8K fitted well with the Brillouin function with the following values: g {sub eff}=1.5, μ B =9.27×10−21 emu, and J=6. These results provide new insights into the development of lanthanide metal complexes with tetraaza.

Multispectral Emissions of Lanthanide-Doped Gadolinium Oxide Nanophosphors for Cathodoluminescence and Near-Infrared Upconversion/Downconversion Imaging

Directory of Open Access Journals (Sweden)

Doan Thi Kim Dung

2016-09-01

Full Text Available Comprehensive imaging of a biological individual can be achieved by utilizing the variation in spatial resolution, the scale of cathodoluminescence (CL, and near-infrared (NIR, as favored by imaging probe Gd2O3 co-doped lanthanide nanophosphors (NPPs. A series of Gd2O3:Ln3+/Yb3+ (Ln3+: Tm3+, Ho3+, Er3+ NPPs with multispectral emission are prepared by the sol-gel method. The NPPs show a wide range of emissions spanning from the visible to the NIR region under 980 nm excitation. The dependence of the upconverting (UC/downconverting (DC emission intensity on the dopant ratio is investigated. The optimum ratios of dopants obtained for emissions in the NIR regions at 810 nm, 1200 nm, and 1530 nm are applied to produce nanoparticles by the homogeneous precipitation (HP method. The nanoparticles produced from the HP method are used to investigate the dual NIR and CL imaging modalities. The results indicate the possibility of using Gd2O3 co-doped Ln3+/Yb3+ (Ln3+: Tm3+, Ho3+, Er3+ in correlation with NIR and CL imaging. The use of Gd2O3 promises an extension of the object dimension to the whole-body level by employing magnetic resonance imaging (MRI.

Rare earth elements in the Pacific and Atlantic Oceans. [Pr, Tb, Ho, Tm, Lu, La, Nd, Sm, Eu, Gd, Yb, Ce

Energy Technology Data Exchange (ETDEWEB)

Baar, H J.W. de; Bacon, M P; Brewer, P G; Bruland, K W

1985-09-01

The first profiles of Pr, Tb, Ho, Tm and Lu in the Pacific Ocean, as well as profiles of La, Ce, Nd, Sm, Eu, Gd and Yb are reported. Concentrations of REE (except Ce) in the deep water are two to three times higher than those observed in the deep Atlantic Ocean. Surface water concentrations are typically lower than in the Atlantic Ocean, especially for the heavier elements Ho,Tm,Yb and Lu. Cerium is strongly depleted in the Pacific water column, but less so in the oxygen minimum zone. The distribution of the REE group is consistent with two simultaneous processes: (1) cycling similar to that of opal and calcium carbonate, and (2) adsorptive scavenging by settling particles and possibly by uptake at ocean boundaries. However, the first process can probably not be sustained by the low REE contents of shells, unless additional adsorption on surfaces is invoked. The second process, adsorptive scavenging, largely controls the oceanic distribution and typical seawater pattern of the rare earths. (author).

Synthesis and characterization of La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III) and Dy(III) complexes of 2-acetylfuran-2-thenoylhydrazone

International Nuclear Information System (INIS)

Singh, B.; Singh, Praveen K.

1998-01-01

The reaction of 2-acetylfuran-2-thenoylhydrazone(afth) with Ln(III) trichlorides yields complexes of the type [Ln(afth)Cl 2 (H 2 O)(EtOH)]Cl, [Ln(III) = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy]. The complexes have been characterized by molar conductance, magnetic susceptibility and TGA and DTA measurements, magnetic susceptibility and TGA and DTA measurements, FAB mass, infrared, proton NMR, electronic absorption and emission spectra. The terbium complex is found to be monomer from the FAB mass spectrum. The IR and NMR spectra suggest neutral tridentate behaviour of the Schiff base. A coordination number seven is proposed around the metal ions. Emission spectra suggest C 3v , symmetry around the metal ion with capped octahedron geometry for the europium complex. (author)

Combined two-photon excitation and d → f energy-transfer in Ir/lanthanide dyads with time-gated selection from a two-component emission spectrum.

Science.gov (United States)

Edkins, Robert M; Sykes, Daniel; Beeby, Andrew; Ward, Michael D

2012-10-14

In a pair of Ir/Eu and Ir/Tb dyads, two-photon excitation of the Ir-phenylpyridine chromophore at 780 nm is followed by partial d → f energy-transfer to give a combination of short-lived Ir-based (blue) and long-lived lanthanide-based (red or green) emission; these components can be selected separately by time-gated detection.

Synthesis, structural, thermal and optical studies of rare earth coordinated complex: Tb(Sal){sub 3}Phen

Energy Technology Data Exchange (ETDEWEB)

Kaur, Gagandeep; Dwivedi, Y. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Rai, S.B., E-mail: sbrai49@yahoo.co.in [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

2011-11-01

Highlights: {yields} RE coordinated complex of Tb(Sal){sub 3}Phen in crystalline phases were synthesized. {yields} Enhancement in luminescence of Tb{sup 3+} was observed in complex on 355 nm excitation. {yields} Fluorescence enhancement is due to the efficient energy transfer from Sal to Tb{sup 3+}. {yields} An observed increase in lifetime of Tb{sup 3+} is due to encapsulation in Sal/Phen network. {yields} The present system is a deserving candidate for LSC when coupled with solar cells. - Abstract: Complexes of salicylic acid (Sal) and 1,10-phenanthroline (Phen) were synthesized coordinated with terbium ion (Tb{sup 3+}) in crystalline phases. The structural characterizations of the lanthanide complex were made using FT-IR, NMR ({sup 1}H and {sup 13}C) and XRD techniques. These measurements confirm the formation of Tb(Sal){sub 3}Phen complex structure. The thermal aspects of the complex were examined using DTA and TGA techniques. An enhancement in luminescence intensity of Tb{sup 3+} ion bands were observed in Tb(Sal){sub 3}Phen complex as compared to TbCl{sub 3} crystals on 355 nm laser excitation. Enhancement is reported due to the efficient energy transfer process from Sal to Tb{sup 3+} ions. This is also confirmed by the time resolved photoluminescence spectroscopy with increase in lifetime of Tb{sup 3+} ions due to encapsulation in Sal/Phen network. Our system in itself can be a deserving candidate for luminescent solar collector material when coupled with solar cells.

Addition compounds between same phosphinoxides and hexafluorophosphates of rare earths (III)

International Nuclear Information System (INIS)

Silva, A.M. da; Melo, S.M.; Souza, E.F. de; Almeida, M.A. de

1984-01-01

Coordination compounds were prepared from salts of lanthanide hexafluorophosphates and three different phosphine oxides: methyldiphenylphosphine oxide (MDPPO), diphenylcyclohexylphosphine oxide (DPcHPO) and phosphoric acid trimethylester (TMxPO). The analytical results indicated the following general formulae : Ln(PF 6 ) 3 .5DPChPO where Ln = La, Eu, Gd, Tb and Dy; Ln(PF 6 ) 3 6MDPPO, where Ln = La, Ce, Nd, Eu, Gd, and Tm; Ln(PF 6 ) 3 .7TMxPO, where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb. The vibrational studies in the infrared region showed that all the phosphine oxides coordination are through the oxygen of the phosphoryl group and confirmed the non-coordination character of the PF - 6 ion. Fluorescence spectra in the visible region for the Eu (III) compounds, at the liquid nitrogen temperature indicated the microsymmetry C sub(3v) as the most probable for the Eu (III) in the compounds Eu (PF 6 ) 3 .5DPChPO and Eu (PF 6 ) 3 .7TMxPO. The symmetry site of the Eu (PF 6 ) 3 .6MDPPO compound is octahedral with tetragonal distortion. (Author) [pt

Vacuum ultraviolet excited luminescence properties of sol–gel derived GdP5O14:Eu3+ powders

International Nuclear Information System (INIS)

Mbarek, Aïcha; Chadeyron, Geneviève; Boyer, Damien; Avignant, Daniel; Fourati, Mohieddine; Zambon, Daniel

2014-01-01

Sol–gel route has successfully been used to synthesize pure and Eu 3+ doped polycrystalline samples of the GdP 5 O 14 pentaphosphates. The as-prepared samples have structurally been characterized using X-ray diffraction. Optical properties in the vacuum ultraviolet (VUV) of Eu 3+ activated GdP 5 O 14 samples prepared either by sol–gel process or solid-state reaction were investigated at room temperature for comparison. In this GdP 5 O 14 host matrix the P 5 O 14 ultraphosphate groups were proved to exhibit an efficient absorption in the VUV range. The excitation spectra recorded in the VUV-UV spectral region from 120 nm to 350 nm have revealed the presence of Gd 3+ 4f–5d interconfiguration transitions, Gd 3+ –O 2− and Eu 3+ –O 2− charge transfer states(CTS)in addition to intraconfiguration transitions of Gd 3+ ions.Furthermore the Gd 3+ →Eu 3+ energy transfer process was investigated and discussed in the framework of the multiphonon relaxation process. Besides, the GdP 5 O 14 :Eu 3+ phosphor led to a strong red emission under 147/172 nm excitation, so that it can be considered as a promising red phosphor for mercury-free lamps and plasma display panels applications. -- Highlights: • Lanthanide pentaphosphates were synthesized by the sol–gel process. • A broad absorption was evidenced in the VUV range for GdP 5 O 14 :Eu 3+ . • An efficient energy transfer was proved from pentaphosphate lattice to Eu 3+ ions

Eu(III) and Tb(III) complexes with the nonsteroidal anti-inflammatory drug carprofen: synthesis, crystal structure, and photophysical properties.

Science.gov (United States)

Zhou, Xianju; Zhao, Xiaoqi; Wang, Yongjie; Wu, Bing; Shen, Jun; Li, Li; Li, Qingxu

2014-12-01

Two new lanthanide complexes with general formula [Ln2(carprofen)6(DMF)2] (Ln = Eu (1), Tb (2), DMF = N,N-dimethylformamide, carprofen = 6-chloro-α-methylcarbazole-2-acetic acid) have been synthesized by a hydrothermal method. Complex 1 was characterized by single-crystal X-ray diffraction (XRD), and it was found to crystallize in the monoclinic space group C2/c. The coordination of the ligand to the lanthanide ion has been investigated by Fourier-transform infrared (FTIR) spectra and ultraviolet-visible (UV-vis) absorption spectra. Complex 1 emits red light, but the antenna effect of the ligand is not effective, whereas complex 2 presents intense green emission with effective energy transfer from the ligand. The different performance of the two complexes is related to the energy matching between the excited states of the lanthanide ion and the triplet state of the ligand. The intramolecular energy transfer mechanisms are also discussed.

Luminescence and magnetic properties of novel nanoparticle-sheathed 3D Micro-Architectures of Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) for bifunctional application

Science.gov (United States)

Krishnan, Rajagopalan; Thirumalai, Jagannathan; Kathiravan, Arunkumar

2015-01-01

For the first time, we report the successful synthesis of novel nanoparticle-sheathed bipyramid-like and almond-like Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) 3D hierarchical microstructures through a simple disodium ethylenediaminetetraacetic acid (Na2EDTA) facilitated hydrothermal method. Interestingly, time-dependent experiments confirm that the assembly-disassembly process is responsible for the formation of self-aggregated 3D architectures via Ostwald ripening phenomena. The resultant products are characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and magnetic measurements. The growth and formation mechanisms of the self-assembled 3D micro structures are discussed in detail. To confirm the presence of all the elements in the microstructure, the energy loss induced by the K, L shell electron ionization is observed in order to map the Fe, Gd, Mo, O, and Eu components. The photo luminescence properties of Fe0.5R0.5(MoO4)1.5 doped with Eu3+, Tb3+, Dy3+ are investigated. The room temperature and low temperature magnetic properties suggest that the interaction between the local-fields introduced by the magnetic Fe3+ ions and the R3+ (La, Gd) ions in the dodecahedral sites determine the magnetism in Fe0.5R0.5(MoO4)1.5:Eu3+. This work provides a new approach to synthesizing the novel Fe0.5R0.5(MoO4)1.5:Ln3+ for bi-functional magnetic and luminescence applications.

Biological toxicity of lanthanide elements on algae.

Science.gov (United States)

Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

2010-08-01

The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Energy transfer processes in Tb(III)-dibenzoylmethanate complexes with phosphine oxide ligands

International Nuclear Information System (INIS)

Silva Junior, Francisco A.; Nascimento, Helenise A.; Pereira, Dariston K.S.; Teotonio, Ercules E.S.; Espinola, Jose Geraldo P.; Faustino, Wagner M.; Sa, Gilberto F.

2013-01-01

The Tb 3+ -β-diketonate complexes [Tb(DBM) 3 L], [Tb(DBM) 2 (NO 3 )L 2 ] and [Tb(DBM)(NO 3 ) 2 (HMPA) 2 ] (DBM = dibenzoylmethanate; L: TPPO triphenylphosphine oxide or HMPA=hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd 3+ complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs). (author)

Energy transfer processes in Tb(III)-dibenzoylmethanate complexes with phosphine oxide ligands

Energy Technology Data Exchange (ETDEWEB)

Silva Junior, Francisco A.; Nascimento, Helenise A.; Pereira, Dariston K.S.; Teotonio, Ercules E.S.; Espinola, Jose Geraldo P.; Faustino, Wagner M., E-mail: teotonioees@quimica.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Quimica; Brito, Hermi F. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica. Departamento de Quimica Fundamental; Felinto, Maria Claudia F.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Sa, Gilberto F. [Universidade Federal de Pernambuco (UFPE/CCEN), Recife, PE (Brazil). Centro de Ciencias Exatas e da Natureza. Departamento de Quimica Fundamental

2013-04-15

The Tb{sup 3+}-{beta}-diketonate complexes [Tb(DBM){sub 3}L], [Tb(DBM){sub 2}(NO{sub 3})L{sub 2}] and [Tb(DBM)(NO{sub 3}){sub 2} (HMPA){sub 2}] (DBM = dibenzoylmethanate; L: TPPO triphenylphosphine oxide or HMPA=hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd{sup 3+} complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs). (author)

Analytical chemistry of lanthanides

International Nuclear Information System (INIS)

Al-Sowdani, K.H.

1986-12-01

Candoluminescence of the lanthanides and the development of instruments for monitoring the phenomenon are described. The use of fluorescence spectroscopy, spectrofluorometry and spectrophotometry for the quantitative chemical analysis of the lanthanides is described. (U.K.)

Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

International Nuclear Information System (INIS)

Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming; An, Ran; Yang, Meng-Lin; Xue, Ganglin

2017-01-01

Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox) 0.5 (H 2 O)] n ·2n(H 2 O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H 2 sfpip)(ox)(H 2 O) 4 ] n ·2n(H 2 O) (Ln=Nd (8) Sm (9)), [H 2 ox=oxalic acid, H 3 sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H 3 sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox 2− anions as linkers to bridge the adjacent layers. Compounds 8–9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1–9 were also investigated. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

Energy Technology Data Exchange (ETDEWEB)

Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN; An, Ran; Yang, Meng-Lin; Xue, Ganglin

2017-01-15

Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox){sub 0.5}(H{sub 2}O)]{sub n}·2n(H{sub 2}O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H{sub 2}sfpip)(ox)(H{sub 2}O){sub 4}]{sub n}·2n(H{sub 2}O) (Ln=Nd (8) Sm (9)), [H{sub 2}ox=oxalic acid, H{sub 3}sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H{sub 3}sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox{sup 2−} anions as linkers to bridge the adjacent layers. Compounds 8–9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1–9 were also investigated. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

Thermodynamics of complexation of lanthanides and some of transition metal ions by 5,5-dimethyl-cyclohexane-2-(2-hydroxyphenyl)-hydrazono-1,3-dione (DCPHD) and its derivatives

International Nuclear Information System (INIS)

Ramadan, A.A.T.; Abdel-Moez, M.S.; El-Shetary, B.A.; Seleim, H.S.

1993-01-01

Equilibrium between DCPHD, DC-4-Cl-PHD, and DC-4-Me-PHD and protons, transition, and lanthanide ions have been investigated at 30 o C by means of potentiometric titration in 75%(v/v) methanol-water mixture containing 0.10M KNO 3 as a constant ionic medium. Thermodynamic parameters(ΔG,ΔH and ΔS) referring to the formation of species HL - ,L -- ,ML +n-2 and ML 2 +n-4 (L -- denotes the ligand anion) have been determined in solutions. The solvent effects on the thermodynamic parameters of the complex formation are discussed in terms of differences in the donor ability of methanol and water solvents. The plots of thermodynamic parameters versus ionic potential (Z 2 /r) of the lanthanide elements is not linear as expected from ionic theory. The obtained curve can be resolved in an initial group (the lighter lanthanides), an intermediate group (Sm-Dy), and a final group (the heavier ones, Tb-Lu). This behavior was explained in terms of differences in the dehydration of lighter lanthanide(III) from that of heavier ones

Physico-chemical characterization of terbium-161-chloride (161TbCl3) radioisotope from irradiated natural gadolinium oxide target

International Nuclear Information System (INIS)

Azmairit Aziz; Nana Suherman

2015-01-01

Currently cancer patients are increasing every year in Indonesia and become the third leading cause of death after heart disease and high blood pressure. Terbium-161 ( 161 Tb) is a low β- emitter (E β - = 0.155 MeV, T 1/2 = 6.9 d) and very similar to 177 Lu in terms of half-life, E β - energy and chemical properties.However, 161 Tb also ejects internal conversion electrons and Auger electrons which can provide a greater therapeutic effect than 177 Lu. Radioisotope of 161 Tb can be produced as a carrier-free for use in labeling of biomolecules as a targeted radiopharmaceutical for cancer therapy. 161 Tb was obtained through 160 Gd(n,γ) 161 Tb nuclear reaction by thermal neutron bombardment on 100 mg of natural gadolinium oxide target in RSG-G.A. Siwabessy at a thermal neutron flux of ~10 14 n.cm -2 .s -1 and followed by radiochemical separation of 161 Tb from Gd isotopes using extraction chromatography method. The physico-chemical characterization of 161 TbCl 3 solution was studied by determination of its radionuclide purity by means of a γ-rays spectrometry with HP-Ge detector coupled to a multichannel analyzer (MCA). Radiochemical purity was determined using paper chromatography and paper electrophoresis methods. The results showed that 161 TbCl 3 radioisotope has a pH of 2, radiochemical purity of 99.64 ± 0.34%, radionuclide purity of 99.69 ± 0.20%, specific activity and radioactive concentration at the end of irradiation (EOI) of 2.26 – 5.31 Ci/mg and 3.84 – 9.03 mCi/mL, respectively. 161 TbCl 3 solution stable for 3 weeks at room temperature with a radiochemical purity of 98.41 ± 0.42%. 161 TbCl 3 solution from irradiated natural gadolinium oxide target has the physico-chemical characteristic that meets the requirements for use as a precursor in preparation of radiopharmaceuticals. (author)

Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

Energy Technology Data Exchange (ETDEWEB)

Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

2016-06-15

Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

Scandium, yttrium and the lanthanides

International Nuclear Information System (INIS)

Hart, F.A.

1987-01-01

This chapter on the chemistry of the coordination complexes of scandium, yttrium and the lanthanides includes sections on the nitrogen and oxygen donor ligands and complex halides of scandium, and the phosphorus and sulfur donor ligands of yttrium and the lanthanides. Complexes with the macrocylic ligands and with halides are also discussed. Sections on the NMR and electronic spectra of the lanthanides are also included. (UK)

Ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb). Intergrowth structures with MgCu{sub 2} and CaCu{sub 5} related slabs

Energy Technology Data Exchange (ETDEWEB)

Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Oldenburg (Germany). Inst. fuer Chemie

2017-07-01

Fourteen ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce{sub 4}Rh{sub 9}Ga{sub 5}, Ce{sub 5}Rh{sub 12}Ga{sub 7}, Ce{sub 7}Rh{sub 18}Ga{sub 11}, Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)}, Nd{sub 4}Rh{sub 9}Ga{sub 5} and Gd{sub 4}Rh{sub 9}Ga{sub 5} were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE{sub 2+n} Rh{sub 3+3n} Ga{sub 1+2n} structure series in the Parthe intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu{sub 2} (Mg{sub 2}Ni{sub 3}Si as ternary variant) and CaCu{sub 5} (CeCo{sub 3}B{sub 2} as ternary variant). Only the Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)} crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y{sub 4}Rh{sub 9}Ga{sub 5} and Curie-Weiss paramagnetism for Gd{sub 4}Rh{sub 9}Ga{sub 5} and Tb{sub 4}Rh{sub 9}Ga{sub 5}. Low-temperature data show ferromagnetic ordering at T{sub C}=78.1 (Gd{sub 4}Rh{sub 9}Ga{sub 5}) and 55.8 K (Tb{sub 4}Rh{sub 9}Ga{sub 5}).

Influence of strain and polycrystalline ordering on magnetic properties of high moment rare earth metals and alloys

International Nuclear Information System (INIS)

Scheunert, G; Ward, C; Hendren, W R; Bowman, R M; Lapicki, A A; Hardeman, R; Mooney, M; Gubbins, M

2014-01-01

Despite being the most suitable candidates for solenoid pole pieces in state-of-the-art superconductor-based electromagnets, the intrinsic magnetic properties of heavy rare earth metals and their alloys have gained comparatively little attention. With the potential of integration in micro and nanoscale devices, thin films of Gd, Dy, Tb, DyGd and DyTb were plasma-sputtered and investigated for their in-plane magnetic properties, with an emphasis on magnetization versus temperature profiles. Based on crystal structure analysis of the polycrystalline rare earth films, which consist of a low magnetic moment fcc layer at the seed interface topped with a higher moment hcp layer, an experimental protocol is introduced which allows the direct magnetic analysis of the individual layers. In line with the general trend of heavy lanthanides, the saturation magnetization was found to drop with increasing unit cell size. In situ annealed rare earth films exceeded the saturation magnetization of a high-moment Fe 65 Co 35 reference film in the cryogenic temperature regime, proving their potential for pole piece applications; however as-deposited rare earth films were found completely unsuitable. In agreement with theoretical predictions, sufficiently strained crystal phases of Tb and Dy did not exhibit an incommensurate magnetic order, unlike their single-crystal counterparts which have a helical phase. DyGd and DyTb alloys followed the trends of the elemental rare earth metals in terms of crystal structure and magnetic properties. Inter-rare-earth alloys hence present a desirable blend of saturation magnetization and operating temperature. (paper)

Pressure-induced polyamorphism in lanthanide-solute metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Li, Liangliang; Li, Renfeng; Liu, Haozhe [Harbin Institute of Technology, Harbin (China); Center for High Pressure Science Technology Advanced Research, Changchun (China); Wang, Luhong [Harbin Institute of Technology, Harbin (China); Qu, Dongdong [School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD (Australia); Zhao, Haiyan [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States); Center for Advanced Energy Studies, University of Idaho, Idaho Falls, ID (United States); Chapman, Karena W.; Chupas, Peter J. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States)

2017-06-15

The electronic structure inheritance of lanthanide-solvent atoms in lanthanide-based metallic glasses has been proposed. Is a polyamorphism possible in lanthanide-solute metallic glasses? So far, polyamorphic phase transitions in metallic glass containing lanthanide have been observed only in lanthanide-solvent metallic glasses. Here, a pressure-induced transition between two distinct amorphous states, accompanied by a 7% volume collapse at ambient pressure, was observed in La{sub 43.4}Pr{sub 18.6}Al{sub 14}Cu{sub 24} metallic glass, with low lanthanide content, by using in situ X-ray total scattering method. The transformation also indicated by changes in short range and medium range order. Thus, it is proposed that the lanthanide-solute metallic glasses also inherit 4f electronic transition from pure lanthanide element in polyamorphic transition. This discovery offers a supplement to research on lanthanide-based metallic glasses, which further provides a new perspective of the polyamorphic transformation in metallic glasses containing lanthanide element. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Extraction chromatography of lanthanides, ch. 8

International Nuclear Information System (INIS)

Siekierski, S.; Fidelis, I.

1975-01-01

The extraction of lanthanides by chelate formation with acidic organophosphorous extractants, by solvation of salts, and in the form of ion pairs is reviewed. The double-double effect and its significance for the lanthanide as well as the actinide separation is discussed. A short survey of the existing data on the enthalpies of lanthanide extraction and on the influence of temperature on their separation factor is given. The resolution ability of columns used for the separation of lanthanides is briefly surveyed

Lanthanide single molecule magnets

CERN Document Server

Tang, Jinkui

2015-01-01

This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs, and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures – an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and...

Seed-mediated synthesis of NaY F4:Y b, Er/NaGdF4 nanocrystals with improved upconversion fluorescence and MR relaxivity

International Nuclear Information System (INIS)

Guo Hai; Li Zhengquan; Qian Haisheng; Hu Yong; Muhammad, Idris Niagara

2010-01-01

Rational combination of different functional lanthanide materials within a single nanocrystal presents a feasible way to develop a multifunctional nanoplatform for various biomedical applications. The conventional methods of synthesizing and integrating two kinds of material together generally involve laborious procedures, whilst codoping different functional ions inside a single lanthanide nanocrystal usually results in a decrease in both its fluorescence and its magnetic resonance relaxivity. Here, we present a seed-mediated synthetic route to prepare core-shell structured NaY F 4 :Y b, Er/NaGdF 4 nanocrystals. Epitaxial growth of a gadolinium layer on an upconversion lanthanide seed not only improves its upconversion fluorescence, but also creates a paramagnetic shell with high magnetic resonance relaxivity. The prepared nanocrystals are uniform in size, stable in water and easy for conjugation after modification, which may have the potential to serve as a versatile imaging tool for smart detection or diagnosis in future biomedical engineering.

Luminescence and energy transfer properties of Eu{sup 3+} and Gd{sup 3+} in ZrO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Villabona-Leal, E.G. [Posgrado en Ciencias Aplicadas, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí. Av. Salvador Nava, 078290 San Luis Potosí (Mexico); Diaz-Torres, L.A.; Desirena, H. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestrcuturados (EMANA), Centro de Investigaciones en Óptica, A. P.1-948, Gto. 37150 León (Mexico); Rodríguez-López, J.L. [División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino Presa San José, Lomas 4a Secc, 78216 San Luis Potosí (Mexico); Pérez, Elías [Instituto de Física, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, 78000 San Luis Potosí (Mexico); Meza, Octavio, E-mail: omeza@ifuap.buap.mx [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla 72570 (Mexico)

2014-02-15

Red luminescence emission in ZrO2:Gd{sup 3+}–Eu{sup 3+} nanocrystal under 250 nm radiation excitation is achieved. These materials exhibit a tetragonal phase that is retained by the presence of lanthanide ions. Thus, a study of the optical properties as a function of the dopant concentration was been carried out without the deleterious effects of having segregation of other crystalline phases. We analyze the emission and lifetime curves as a function of dopant concentration through a rate equation simulation, finding an excellent fitting. As results, the nonradiative and radiative relaxation constants, as well as a quantitative estimation of the energy transfer processes among Eu{sup 3+}, Gd{sup 3+} and O{sup 2−} ions are reported for the first time. The proposed model can be extended (or applicable) to explain the fluorescence dynamics in other nanomaterials doped with Eu{sup 3+} and Gd{sup 3+} under UV excitation. -- Highlights: • ZrO{sub 2} nanocrystal exhibits a tetragonal phase in the presence of Eu and Gd dopants. • Emission and lifetimes as a function of dopant concentration were analyzed by rate equation model. • Quantitative estimation of the energy transfer processes among Eu{sup 3+}, Gd{sup 3+} and O{sup 2−} ions are reported.

Syntheses, structures and properties of four 3D microporous lanthanide coordination polymers based on 3,5-pyrazoledicarboxylate and oxalate ligands

International Nuclear Information System (INIS)

Song, Juan; Wang, Ji-Jiang; Hu, Huai-Ming; Wu, Qing-Ran; Xie, Juan; Dong, Fa-Xin; Yang, Meng-Lin; Xue, Gang-Lin

2014-01-01

Four three-dimensional lanthanide coordination polymers with reversible structural interconversions, [Ln 2 (Hpdc) 2 (C 2 O 4 )(H 2 O) 4 ] n ·2nH 2 O [Ln=Sm (1), Eu (2), Tb (3) and Dy (4)], have been synthesized by hydrothermal reactions of lanthanide nitrates with 3,5-pyrazoledicarboxylic (H 3 pdc) and oxalic acids. It is noteworthy that there is an in situ reaction in 1, in which H 3 pdc was decomposed into (ox) 2− with Cu(II)–Sm(III) synergistic effect under hydrothermal conditions. These compounds are isostructural and crystallized in the monoclinic P2 1 /c space group. The Ln(III) ions are eight-coordinated with dodecahedron coordination geometry. These polyhedra are linked by oxalate groups to form 1D zigzag chain, which are further connected by 3,5-pyrazoledicarboxylate to extend similar 3D frameworks with channels along c-axis in 1–4. These coordination polymers display the characteristic emission bands of the Ln(III) ions in the solid state and possess good thermal stabilities. - Graphical abstract: Four 3D microporous lanthanide coordination polymers with reversible structural interconversion have been synthesized. They exhibit characteristic emission bands of the lanthanide ions and possess great thermal stability. - Highlights: • Four lanthanide coordination polymers have been hydrothermal synthesized. • There is an in situ reaction in 1 in which H 3 pdc was decomposed into (ox) 2− with the Cu(II)–Sm(III) synergistic effect under hydrothermal conditions. • TGA and XRD studies reveal that upon hydration–dehydration, compounds 1–4 undergo a reversible structural interconversion process through a cooling-heating cycle. • Compounds 1–4 exhibit characteristic lanthanide-centered luminescence

Lanthanide single molecule magnets

Energy Technology Data Exchange (ETDEWEB)

Tang, Jinkui; Zhang, Peng [Chinese Academy of Sciences, Changchun (China). Changchun Inst. of Applied Chemistry

2015-10-01

This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures - an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and explore new directions.

Phosphors doped with Dy3+ and Gd3+ for lighting

International Nuclear Information System (INIS)

Su, Q; Pei, Z.; Zeng, Q.; Chi, L.

1998-01-01

Full text: Some heavy lanthanide ions with even atomic number such as Dy 3+ and Gd 3+ are abundant in the ion adsorption type deposit of China. Their price is cheap and they have specific spectroscopic properties which can be used as phosphors. Dy 3i on has two dominant bands in the emission spectrum. The yellow band (575 nm) corresponds to the hypersensitive transition 4 F 9/2 → 6 H 13/2 (ΔL=2, ΔJ=2), and the blue band (485 nm) corresponds to the 4 F 9/2 → 6 H 15/2 transition. Factors which influence on the yellow- to-blue intensity ratio (Y/B) were investigated. Adjusting to a suitable Y/B, Dy 3+ will emit white light with high colour temperature and can be used for lighting. But Dy 3+ ion has only narrow excitation bands of f-f transitions ranging from 300-500 nm, no broad excitation band such as charge transfer band or f-d transition band exists in the UV region 200-300 nm. Hence its luminescent efficiency is low when it is excited by UV radiation emitted from the mercury plasma. This is one of the drawbacks to its use as lamp phosphor. However, this can be overcome by sensitisation with Gd 3+ , Pb 2+ or other sensitisers such as vanadate shown in this report. Gd 3+ is not only a good matrix, but also a good sensitiser. Using its 8 S 7/2 → 6 D, 6 I and 6 P transitions, the UV excitation energy can be absorbed and transferred to the activator such as Dy 3+ . Therefore, in some cases Gd 3+ is better than Y 3+ which is optical inert as a matrix. For the phosphor Ca 1.96 Pb 0.04 RE 7.9 Dy 0.1 (SiO 4 ) 6 O 2 prepared by sol-gel method, the intensity of Dy 3+ in the Gd 3+ compound (RE=Gd 3+ ) is six times that in the Y 3+ compound. Some new phosphors doped with Dy 3+ and Gd 3+ prepared in our laboratory are reported

Heat capacity of RFe{sub x}Mn{sub 12-x} (R = Gd, Tb and Dy) compounds: wiping out a cooperative 4f-4f exchange interaction by breaking the 3d-4f magnetic symmetry

Energy Technology Data Exchange (ETDEWEB)

Pique, C; Blanco, J A; Abad, E [Departamento de Fisica, Universidad de Oviedo, Campus de Viesques, E-33204 Gijon (Spain); Burriel, R; Artigas, M [Instituto de Ciencia de Materiales de Aragon (CSIC-Universidad de Zaragoza), E-50009 Zaragoza (Spain); Fernandez-RodrIguez, J [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France)], E-mail: pique@uniovi.es

2008-08-27

Using adiabatic calorimetry the heat capacity of a series of RFe{sub x}Mn{sub 12-x} (R = Gd, Tb and Dy) compounds has been measured from 3 to 350 K. The substitution of Fe for Mn in RFe{sub x}Mn{sub 12-x} influences both the magnetic interactions on the 3d sublattice and the magnetism of R (the Neel temperature doubles on going from x = 0 to 6 and the compounds become ferromagnetic for x = 8 with Curie temperatures of around 300 K). In pure TbMn{sub 12} the heat-capacity data shows a {lambda}-type anomaly associated with the independent cooperative magnetic ordering of the R sublattice ({approx}5 K), while the anomaly related to the Mn magnetic ordering ({approx}100 K) is rather smooth, as observed in other itinerant magnetic systems such as YMn{sub 12}. In contrast, the substitution of Fe for Mn leads, on the one hand, to a more localized magnetic behaviour of the 3d sublattice, and, on the other, to magnetic polarization effects between the 3d and 4f sublattices, together with the disappearance of the cooperative magnetic ordering of the R sublattice due to the breaking of the antiferromagnetic symmetry in the 3d sublattice. This is reflected in the heat-capacity curve through a smooth Schottky-like anomaly. In the case of Gd compounds the magnitude of the exchange molecular-field parameter has been deduced by fitting the magnetic contribution to the heat capacity within a simple mean-field model. From this analysis we found that this molecular field acting on the rare-earth site increases with the iron concentration, reaching values as large as 48 T for the concentration x = 6. A similar analysis of the heat capacity in the ordered phase on the Tb compounds also leads to an enhancement of the molecular field with increasing Fe content. These results allow checking the possible crystal-field parameters for these RFe{sub x}Mn{sub 12-x} compounds.

Fabrication and photoluminescence properties of color-tunable light emitting lanthanide doped GdVO{sub 4} hierarchitectures

Energy Technology Data Exchange (ETDEWEB)

Amurisana, Bao, E-mail: amurisana@163.com [Institute of Chemical Biology, Hohhot Vocational College, Hohhot 010051 (China); Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China); Bao, Lihong [Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China); Bao, Liang [Institute of Chemical Biology, Hohhot Vocational College, Hohhot 010051 (China); Tegus, O., E-mail: tegusph@imnu.edu.cn [Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China)

2017-04-15

The flower-like GdVO{sub 4}:Ln{sup 3+}( Ln{sup 3+}=Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+}, Tm{sup 3+}) hierarchitectures have been successfully synthesized on a glass slide substrate through a one-pot hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na{sub 2}H{sub 2}L, where L{sup 4-}=(CH{sub 2}COO){sub 2}N(CH{sub 2}){sub 2}N(CH{sub 2}COO){sub 2}{sup 4-}). A high density and ordered flower-like GdVO{sub 4}:Ln{sup 3+} hierarchitectures grew epitaxially on glass substrate. The as-prepared flower-like architectures with the size about 6 μm are constructed by the numerous radially oriented single-crystalline nanorods with the width from 20 nm to 200 nm and the length from 500 nm to 3 μm. The morphologies, the thickness, and the density of as-grown flower clusters can be readily tuned by tailoring the growth time and Na{sub 2}H{sub 2}L/Gd{sup 3+} molar ratio. The possible formation mechanism of flower-like GdVO{sub 4}:Ln{sup 3+} hierarchitectures is discussed on the basis of the results from the controlled experiments under hydrothermal conditions. Because of an energy transfer from vanadate groups to dopants, the flower-like GdVO{sub 4}:Ln{sup 3+}( Ln{sup 3+}=Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+} and Tm{sup 3+}) superstructures showed strong characteristic dominant emissions of the Eu{sup 3+}, Dy{sup 3+}, Sm{sup 3+} and Tm{sup 3+} ions at 617 nm ({sup 5}D{sub 0}→{sup 7}F{sub 2}, strong red), 575 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 13/2}, yellow), 604 nm ({sup 4}G{sub 5/2}→{sup 6}H{sub 7/2}, orange-red) and 476 nm ({sup 1}G{sub 4}–{sup 3}H{sub 6}, blue) under ultraviolet excitation, respectively.Further, the emission color of the product can also be tuned by selecting the dopant Ln{sup 3+} with characteristic emissions and varying the concentration ratio of co-doping activators. This approach could be extended to the fabrication of hierarchical structures for other oxide micro/nanomaterials, and may provide a general way to achieve multicolor

Sparkle/PM7 Lanthanide Parameters for the Modeling of Complexes and Materials.

Science.gov (United States)

Dutra, José Diogo L; Filho, Manoel A M; Rocha, Gerd B; Freire, Ricardo O; Simas, Alfredo M; Stewart, James J P

2013-08-13

The recently published Parametric Method number 7, PM7, is the first semiempirical method to be successfully tested by modeling crystal structures and heats of formation of solids. PM7 is thus also capable of producing results of useful accuracy for materials science, and constitutes a great improvement over its predecessor, PM6. In this article, we present Sparkle Model parameters to be used with PM7 that allow the prediction of geometries of metal complexes and materials which contain lanthanide trications. Accordingly, we considered the geometries of 224 high-quality crystallographic structures of complexes for the parameterization set and 395 more for the validation of the parameterization for the whole lanthanide series, from La(III) to Lu(III). The average unsigned error for Sparkle/PM7 for the distances between the metal ion and its coordinating atoms is 0.063Å for all lanthanides, ranging from a minimum of 0.052Å for Tb(III) to 0.088Å for Ce(III), comparable to the equivalent errors in the distances predicted by PM7 for other metals. These distance deviations follow a gamma distribution within a 95% level of confidence, signifying that they appear to be random around a mean, confirming that Sparkle/PM7 is a well-tempered method. We conclude by carrying out a Sparkle/PM7 full geometry optimization of two spatial groups of the same thulium-containing metal organic framework, with unit cells accommodating 376 atoms, of which 16 are Tm(III) cations; the optimized geometries were in good agreement with the crystallographic ones. These results emphasize the capability of the use of the Sparkle Model for the prediction of geometries of compounds containing lanthanide trications within the PM7 semiempirical model, as well as the usefulness of such semiempirical calculations for materials modeling. Sparkle/PM7 is available in the software package MOPAC2012, at no cost for academics and can be obtained from http://openmopac.net.

Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

Science.gov (United States)

Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming; An, Ran; Yang, Meng-Lin; Xue, Ganglin

2017-01-01

Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox)0.5(H2O)]n·2n(H2O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H2sfpip)(ox)(H2O)4]n·2n(H2O) (Ln=Nd (8) Sm (9)), [H2ox=oxalic acid， H3sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H3sfpip resulted in two types of structures. Compounds 1-7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox2- anions as linkers to bridge the adjacent layers. Compounds 8-9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1-7 to 8-9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1-9 were also investigated.

Transport behaviour of the lanthanide 152Eu(III), 153Gd(III) and 170Tm(III) and transplutonium element 254Es(III), 244Cm(III), 241Am(III), 249Cf(III) and 249Bk(III) ions in aqueous solutions at 298 K

International Nuclear Information System (INIS)

Ouerfelli, N.

2014-01-01

Ionic self-diffusion coefficients (D) for trivalent radiotracers, lanthanide and actinide ions have been determined in concentrated aqueous solutions of supporting electrolytes of Gd(NO 3 ) 3 -HNO 3 or Nd(ClO 3 ) 4 -HClO 4 up to 1.5 mol L -1 at 298.15 K and pH 2.50 by the open-end capillary method. The data obtained in large range of concentrations, allow to derive the limiting value D deg, the validity of the Onsager limiting law and a more extended law. This study contributes to demonstrate similarities in transport and structure properties between 4f and 5f trivalent ions explained by a similar electronic configuration, ionic radius and hydration number. An empirical equation is suggested for predicting ionic hydration number with a good precision. (author)

A new promising phosphor, Na3La2(BO3)3:Ln (Ln=Eu, Tb)

International Nuclear Information System (INIS)

Li Zhihua; Zeng Jinghui; Zhang Guochun; Li Yadong

2005-01-01

We present an efficient way to search a host for ultraviolet (UV) phosphor from UV nonlinear optical (NLO) materials. With the guidance, Na 3 La 2 (BO 3 ) 3 (NLBO), as a promising NLO material with a broad transparency range and high damage threshold, was adopted as a host material for the first time. The lanthanide ions (Tb 3+ and Eu 3+ )-doped NLBO phosphors have been synthesized by solid-state reaction. Luminescent properties of the Ln-doped (Ln=Tb 3+ , Eu 3+ ) sodium lanthanum borate were investigated under UV ray excitation. The emission spectrum was employed to probe the local environments of Eu 3+ ions in NLBO crystal. For red phosphor, NLBO:Eu, the measured dominating emission peak was at 613 nm, which is attributed to 5 D - 7 F 2 transition of Eu 3+ . The luminescence indicates that the local symmetry of Eu 3+ in NLBO crystal lattice has no inversion center. Optimum Eu 3+ concentration of NLBO:Eu 3+ under UV excitation with 395 nm wavelength is about 30 mol%. The green phosphor, NLBO:Tb, showed bright green emission at 543 with 252 nm excited light. The measured concentration quenching curve demonstrated that the maximum concentration of Tb 3+ in NLBO was about 20%. The luminescence mechanism of Ln-doped NLBO (Tb 3+ and Eu 3+ ) was analyzed. The relative high quenching concentration was also discussed

Hydrothermal synthesis, structure, and optical properties of two nanosized Ln{sub 26} rate at CO{sub 3} (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu; Huang, Lian; Miao, Hao; Wan, Hong Xiang; Mei, Hua; Liu, Ying [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University (China); Xu, Yan [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University (China); State Key Laboratory of Coordination Chemistry, Nanjing Tech University (China)

2015-02-16

Two Ln{sub 26} rate at CO{sub 3} (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs) formulated as [Dy{sub 26}Cu{sub 3}(Nic){sub 24}(CH{sub 3}COO){sub 8}(CO{sub 3}){sub 11}(OH){sub 26}(H{sub 2}O){sub 14}]Cl . 3 H{sub 2}O (1; HNic=nicotinic acid) and [Tb{sub 26}NaAg{sub 3}(Nic){sub 27}(CH{sub 3}COO){sub 6}(CO{sub 3}){sub 11}(OH){sub 26}Cl(H{sub 2}O){sub 15}] . 7.5 H{sub 2}O (2) have been successfully synthesized by hydrothermal methods and characterized by IR, thermogravimetric analysis (TGA), elemental analysis, and single X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a=35.775(12) Aa, b=33.346(11) Aa, c=24.424(8) Aa, β=93.993(5) , V=29065(16) Aa{sup 3}, whereas 2 crystallizes in the triclinic space group P anti 1 with a=20.4929(19) Aa, b=24.671(2) Aa, c=29.727(3) Aa, α=81.9990(10) , β=88.0830(10) , γ=89.9940(10) , V=14875(2) Aa{sup 3}. Structural analysis indicates the framework of 1 is a 3D perovskite-like structure constructed out of CO{sub 3} rate at Dy{sub 26} building units and Cu{sup +} centers by means of nicotinic acid ligand bridging. In 2, however, nanosized CO{sub 3} rate at Tb{sub 26} units and [Ag{sub 3}Cl]{sup 2+} centers are connected by Nic{sup -} bridges to give rise to a 2D structure. It is worth mentioning that this kind of 4d-4f cluster-based MOF is quite rare as most of the reported analogous compounds are 3d-4f ones. Additionally, the solid-state emission spectra of pure compound 2 at room temperature suggest an efficient energy transfer from the ligand Nic{sup -} to Tb{sup 3+} ions, which we called the ''antenna effect''. Compound 2 shows a good two-photon absorption (TPA) with a TPA coefficient of 0.06947 cm GM{sup -1} (1 GM = 10{sup -50} cm{sup 4} s photon{sup -1}), which indicates that compound 2 might be a good choice for third-order nonlinear optical materials. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of applied hydrostatic pressure on the quenching kinetics, and electronic and molecular structure of eight and nine-coordinate lanthanide complexes in solution

International Nuclear Information System (INIS)

Maupin, C.L.; Riehl, J.P.

1998-01-01

Full text: Applied hydrostatic pressure may be used as a probe of the reaction mechanism for various solution reactions involving lanthanide ions. In this work we report on the use of high pressure to probe the mechanism of enantioselective quenching between racemic luminescent lanthanide complexes containing Dy(III) Tb(III) and Eu(III), and optically active transition metal complexes as quenchers. Diastereomeric rate constants are obtained from a biexponential fit of the luminescence decay. Particular attention will be given to solvation effects on the measured diastereomeric rate constants. The source of chirality is ascribed to a enantioselective rearrangement step within a bimolecular 'encounter' complex yielding a intermolecular geometry in which the energy transfer is efficient. The effect of high pressure on the molecular and electronic structure of these complexes will also be discussed

New neutron-rich isotope production in 154Sm+160Gd

Directory of Open Access Journals (Sweden)

Ning Wang

2016-09-01

Full Text Available Deep inelastic scattering in 154Sm+160Gd at energies above the Bass barrier is for the first time investigated with two different microscopic dynamics approaches: improved quantum molecular dynamics (ImQMD model and time dependent Hartree–Fock (TDHF theory. No fusion is observed from both models. The capture pocket disappears for this reaction due to strong Coulomb repulsion and the contact time of the di-nuclear system formed in head-on collisions is about 700 fm/c at an incident energy of 440 MeV. The isotope distribution of fragments in the deep inelastic scattering process is predicted with the simulations of the latest ImQMD-v2.2 model together with a statistical code (GEMINI for describing the secondary decay of fragments. More than 40 extremely neutron-rich unmeasured nuclei with 58≤Z≤76 are observed and the production cross sections are at the order of μb to mb. The multi-nucleon transfer reaction of Sm+Gd could be an alternative way to synthesize new neutron-rich lanthanides which are difficult to be produced with traditional fusion reactions or fission of actinides.

Spectroscopic studies of some lanthanide(III nitrate complexes synthesized from a new ligand 2,6-bis-(salicylaldehyde hydrazone-4-chlorophenol

Directory of Open Access Journals (Sweden)

A.S. Sall

2003-06-01

Full Text Available The ligand 2,6-bis-(salicylaldehydehydrazone-4-chlorophenol (H5L and its binuclear lanthanide(III nitrate complexes {[Ln2(H4L3(NO3](NO32.mH2O} where Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb and Y, have been synthesized. The complexes were characterized by chemical analysis, conductance, magnetic moment measurements and infrared spectra. Infrared study indicates that the ligand behaves both as neutral and ionic O donors and as neutral N donors.

Scandium, yttrium and the lanthanide metals

International Nuclear Information System (INIS)

Brown, Paul L.; Ekberg, Christian

2016-01-01

The hydroxide and oxide phases that exist for scandium(III) include scandium hydroxide, which likely has both amorphous and crystalline forms, ScOOH(s), and scandium oxide. This chapter presents the data selected for the stability constants of the polymeric hydrolysis species of scandium at zero ionic strength. The behaviour of yttrium, and the lanthanide metals, in the environment is largely dependent on their solution equilibria. Hydrolysis and other complexation reactions of yttrium and the lanthanide metals are important in the disposal of nuclear waste. The trivalent lanthanide metals include lanthanum(III) through lutetium(III). A number of studies have reported a tetrad effect for the geochemical behaviour of the lanthanide series, including stability constants and distribution coefficients. The solubility of many of the lanthanide hydroxide phases has been studied at fixed ionic strength. In studying the hydrolysis of cerium(IV), a number of studies have utilised oxidation-reduction reactions in determining the relevant stability constants.

Preparation and characterization of electroluminescent devices based on complexes of β-diketonates of Tb3+, Eu3+, Gd3+ ions with macrocyclic ligands and UO22+ films

International Nuclear Information System (INIS)

Gibelli, Edison Bessa

2010-01-01

Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR 3+ ) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth β-diketonate complexes (Tb 3+ , Eu 3+ and Gd 3+ ) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO 2 2+ . The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

International Nuclear Information System (INIS)

Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

2015-01-01

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln 2 (phen) 2 (SO 4 ) 3 (H 2 O) 2 ] n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)] n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO 4 2− anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic–inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature. - Graphical abstract: Lanthanide sulfates and lanthanide sulfonate-carboxylates have been hydrothermally synthesized. Interestingly, sulfate anions, 2-sulfobenzoate and benzoate ligands came from the in situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. - Highlights: • In situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. • The organic–inorganic hybrid lanthanide sulfates with one-dimensional column-like structure. • The dinuclear lanthanide sulfonate-carboxylates. • The emission spectra exhibit the characteristic transition of 5 D 0 → 7 F J (J=0–4) of the Eu(III)

Hydration of the lanthanide ions 152Eu(III), 153Gd(III) and 170Tm(III) in aqueous solutions at 298 K and similarity with the transplutonium element ions 254Es(III), 244Cm(III), 241Am(III), 249Cf(III) and 249Bk(III)

International Nuclear Information System (INIS)

Ouerfelli, N.; Latrous, H.; Ammar, M.; Das, D.; Oliver, J.

2013-01-01

The open-end capillary method is used for the determination of ionic self-diffusion coefficients (D) for trivalent radiotracer, lanthanide and actinide ions are reported in concentrated aqueous solutions of supporting electrolytes of Gd(NO 3 ) 3 -HNO 3 or Nd(ClO 3 ) 4 -HClO 4 up to 1.5 mol.L -1 at 298.15 K and pH 2.50. The data obtained in large range of concentrations, allow deriving the limiting value D°, the validity of the Onsager limiting law and a more extended law. This study contributes to demonstrate similarities in transport and structure properties between 4f and 5f trivalent ions explained by a similar electronic configuration, ionic radius and hydration number. (author)

Detection scheme for bioassays based on 2,6-pyridinedicarboxylic acid derivatives and enzyme-amplified lanthanide luminescence

Energy Technology Data Exchange (ETDEWEB)

Steinkamp, Tanja [Department of Chemical Analysis, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Karst, Uwe [Department of Chemical Analysis, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)]. E-mail: u.karst@utwente.nl

2004-11-15

2,6-Pyridinedicarboxylic acid (PDC) and its derivatives are introduced as a new sensitizer system for enzyme-amplified lanthanide luminescence (EALL), a detection scheme for bioassays, which combines enzymatic amplification with time-resolved luminescence measurements of lanthanide chelates. Various PDC esters have been synthesized as esterase substrates that are cleaved to PDC in the presence of the enzyme. PDC forms luminescent complexes with Tb(III) or Eu(III), and the evaluation of the reaction is used for the selective and sensitive detection of esterases. For an esterase from hog liver a limit of detection of 10{sup -3} u/mL (equivalent to 10{sup -9} mol/L) and a limit of quantification of 3 x 10{sup -3} u/mL (equivalent to 3 x 10{sup -9} mol/L) could be achieved. As a second model reaction, xanthine oxidase (XOD) catalyzes the oxidation of 2,6-pyridinedicarboxaldehyde to PDC. Here, the limit of detection was 3 x 10{sup -3} u/mL and the limit of quantification 10{sup -2} u/mL for XOD from microorganisms. Major advantage of the tridentate PDC ligand is the possibility to perform all steps of the assay within or close to the physiological pH range, while the established EALL schemes based on bidentate salicylates or bisphenols have to be carried out at strongly alkaline pH to ensure sufficient complexation with the lanthanides.

Charge Carrier Trapping Processes in RE2O2S (RE = La, Gd, Y, and Lu)

NARCIS (Netherlands)

Luo, H.; Bos, A.J.J.; Dorenbos, P.

2017-01-01

Two different charge carrier trapping processes have been investigated in RE2O2S:Ln3+ (RE = La, Gd, Y, and Lu; Ln = Ce, Pr, and Tb) and RE2O2S:M (M = Ti4+ and Eu3+). Cerium, praseodymium and terbium act as recombination centers and hole trapping centers while host intrinsic defects provide the

Rationalization of the lanthanide-ion-driven magnetic properties in a series of 4f-5d cyano-bridged chains

NARCIS (Netherlands)

Tanase, S.; Ferbinteanu, M.; Cimpoesu, F.

2011-01-01

Magnetic properties of new d-f cyanido-bridged 1D assemblies [RE(pzam)3(H2O)W(CN)8]·H2O (RE(III) = Gd, 1, Tb, 2, Dy, 3; pzam = pyrazine-2-carboxamide) were studied by temperature- and field-dependent magnetization measurements. No evidence for 3D interchain magnetic ordering is found above 2 K.

Determination of Debye temperatures and Lamb-Mössbauer factors for LnFeO3 orthoferrite perovskites (Ln  =  La, Nd, Sm, Eu, Gd)

Science.gov (United States)

Scrimshire, A.; Lobera, A.; Bell, A. M. T.; Jones, A. H.; Sterianou, I.; Forder, S. D.; Bingham, P. A.

2018-03-01

Lanthanide orthoferrites have wide-ranging industrial uses including solar, catalytic and electronic applications. Here a series of lanthanide orthoferrite perovskites, LnFeO3 (Ln  =  La Nd; Sm; Eu; Gd), prepared through a standard stoichiometric wet ball milling route using oxide precursors, has been studied. Characterisation through x-ray diffraction and x-ray fluorescence confirmed the synthesis of phase-pure or near-pure LnFeO3 compounds. 57Fe Mössbauer spectroscopy was performed over a temperature range of 10 K-293 K to observe hyperfine structure and to enable calculation of the recoil-free fraction and Debye temperature (θ D) of each orthoferrite. Debye temperatures (Ln  =  La 474 K Nd 459 K Sm 457 K Eu 452 K Gd 473 K) and recoil-free fractions (Ln  =  La 0.827; Nd 0.817; Sm 0.816; Eu 0.812; Gd 0.826) were approximated through minimising the difference in the temperature dependent experimental centre shift and theoretical isomer shift, by allowing the Debye temperature and isomer shift values to vary. This method of minimising the difference between theoretical and actual values yields Debye temperatures consistent with results from other studies determined through thermal analysis methods. This displays the ability of variable-temperature Mössbauer spectroscopy to approximate Debye temperatures and recoil-free fractions, whilst observing temperature induced transitions over the temperature range observed. X-ray diffraction and Rietveld refinement show an inverse relationship between FeO6 octahedral volume and approximated Debye temperatures. Raman spectroscopy show an increase in the band positions attributed to soft modes of Ag symmetry, Ag(3) and Ag(5) from La to GdFeO3 corresponding to octahedral rotations and tilts in the [0 1 0] and [1 0 1] planes respectively.

Sensitization of uranium fluorescence using 2,6-pyridinedicarboxylic acid: Application for the determination of uranium in the presence of lanthanides

International Nuclear Information System (INIS)

Maji, S.; Viswanathan, K.S.

2009-01-01

The 2,6-pyridinedicarboxylic acid (PDA) has been shown to efficiently sensitize and enhance the fluorescence of uranium in aqueous medium. Interestingly, this ligand stabilizes the UO 2 2+ species, which without the ligand is known to be in a negligible concentration, in aqueous medium at pH 6. The ligand sensitized enhancement of UO 2 2+ fluorescence by PDA, provides an analytical tool for the determination of uranium at trace levels, in aqueous medium. Furthermore, PDA is also known to enhance the fluorescence of lanthanides; consequently, the simultaneous determination of uranium and lanthanides, using PDA as a fluorescence sensitizing agent, becomes a possibility, which has been demonstrated in this work. We have shown that the use of PDA yields detection limits of 2.2x10 -7 M for UO 2 2+ , 1x10 -8 M for Tb 3+ and 5x10 -9 M for Eu 3+ in the simultaneous determination of these analytes.

Luminescent, magnetic and ferroelectric properties of noncentrosymmetric chain-like complexes composed of nine-coordinate lanthanide ions.

Science.gov (United States)

Li, Xi-Li; Chen, Chun-Lai; Xiao, Hong-Ping; Wang, Ai-Ling; Liu, Cai-Ming; Zheng, Xianjun; Gao, Li-Jun; Yang, Xiao-Gang; Fang, Shao-Ming

2013-11-21

Reaction of the chiral ligand (-)-4,5-pinenepyridyl-2-pyrazine (L) with Ln(hfac)3·2H2O precursors [hfac(-) = 1,1,1,5,5,5-hexafluoroacetylacetonate, Ln = Sm(3+) (1), Eu(3+) (2), Tb(3+) (3) and Dy(3+) (4)] in methanol solution led to the formation of four noncentrosymmetric lanthanide complexes with the general formula [Ln(hfac)3L]n·H2O. The single-crystal X-ray diffraction analyses revealed that they are isostructural and take a one-dimensional (1D) chain structure based on the Ln(hfac)3L repeating units, in which the nine-coordinate Ln(3+) ions reside in a tricapped trigonal prism (TTP) environment never reported in previous 1D chain lanthanide complexes. The investigations of their photophysical properties showed that complexes 1, and 3 exhibit characteristic emissions of Sm(3+), Eu(3+) and Tb(3+) ions with respective luminescent lifetime values of 0.065, 1.066 and 0.129 ms, while complex 4 does not display any emission. The different luminescent intensities and lifetimes among them were further discussed in detail. Moreover, the magnetic properties of complexes 1-4 were assessed with a special emphasis on the Dy(3+) complex 4. Alternating-current (ac) magnetic susceptibility measurements indicated that field-induced two-step slow magnetic relaxation processes were observed in 4, indicating the single-molecule magnet (SMM) behavior of 4. In addition, the noncentrosymmetric complexes 1-4 crystallizing in the same polar point group (Cs) exhibit both ferroelectric and nonlinear optical properties at room temperature. All these features make them multifunctional crystalline molecule materials.

Lanthanide complexation in aqueous solutions

International Nuclear Information System (INIS)

Choppin, G.R.

1984-01-01

The lanthanide elements form an extended series of cations with the same charge, slightly varying radii and useful magnetic and spectroscopic properties. Their use in technology is growing rapidly as their properties are more fully explored. The lanthanides also offer scientists valuable and often unique probes for investigating a variety of chemical and physical phenomena. This review has attempted to call attention to these latter uses without trying to provide a thorough discussion of all the relevant literature. Hopefully, awareness of the more interesting facets of present studies of lanthanide complexes in aqueous solution will spur even more advances in the use of these elements. (Auth.)

Preparation and spectral analysis of a new Tb3+-doped CaO-MgO-SiO2 glass ceramics

International Nuclear Information System (INIS)

Cheng Jinshu; Tian Peijing; Zheng Weihong; Xie Jun; Chen Zhenxia

2009-01-01

Tb 3+ -doped CaO-MgO-SiO 2 glass ceramics have been prepared and characterized. The structure and optical properties of the glass ceramics were studied by XRD, SEM, Raman, and fluorescence spectra. The precipitated crystalline phase in the glass ceramics was columnar CaMgSi 2 O 6 . Raman spectra showed the introduction of rare earth nearly had no influence on the sample structure. Fluorescence measurements showed that Tb 3+ ions entered into the diopside crystalline phase and induced a much stronger emission in the glass ceramics than that in the corresponding glass. With increase of Tb 3+ content and the introduction of Gd 3+ , the fluorescence intensity of the luminescent glass ceramic increased

Effect of terbium substitution on the magnetocaloric properties of Gd3Ga5O12

International Nuclear Information System (INIS)

Reshmi, C.P.; Savitha Pillai, S.; Varma, Manoj Raama; Suresh, K.G.

2011-01-01

The magnetic refrigeration is an environment friendly cooling technology based on magnetocaloric effect. The most crucial ingredient behind a magnetic refrigerator is a magnetic material which possesses large magnetocaloric effect. Certain materials when placed in a magnetic field suddenly get heats up and suddenly cooled down by the application and the removal of magnetic field due to their change in entropy. This is measured either in terms of isothermal entropy change and adiabatic temperature change observed when the applied magnetic field is varied. The refrigerators which operate below 15K have applications in liquefying helium and for the development of space based cooling system for the space crafts. The material of choice in this temperature range is rare earth gallium garnets. Rare earth garnets are complex ceramic oxides having the chemical formula A 3 B 2 C 3 O 12 have attracted attention due to their interesting magnetic properties. The magnetism in R 3 Ga 5 O 12 is due to the exchange interaction between the rare earth spins. In the proposed work we have chosen Gd 3 Ga 5 O 12 as parent material, substituted Tb systematically in the place of Gd. The structural studies were done by using Rietveld analysis of X-Ray diffraction. There is a systematic variation of volume and lattice parameter upon substitution of Tb. The magnetic characterizations were done by a vibrating sample magnetometer. The experimental magnetic moments of the materials were calculated from the M-T curve by using Curie-Weiss fit and are good agreement with the theoretical values. There is a systematic increase of magnetic moments by Tb substitution. The magnetocaloric effect is calculated by using the integrated Maxwell's relation from the magnetization data. At low magnetic fields the Tb substituted compounds show good MCE values than GGG. Tb substitution enhances the magnetocaloric effect at low magnetic fields and the ΔS M values are higher for x = 1 and 3 at 1T. Hence these

Treatment: Latent TB Infection (LTBI) and TB Disease

Science.gov (United States)

... Adverse Events TB Treatment of Persons Living with HIV TB Treatment and Pregnancy TB Treatment for Children Drug-Resistant TB Research TB Epidemiologic Studies Consortium Research Projects Publications TB Trials Consortium Study ...

Yttrium and lanthanide nitrate complexes of N,N1-bis(4-antipyryl methylidene) ethylenediamine

International Nuclear Information System (INIS)

Joseph, Siby; Radhakrishnan, P.K.

1998-01-01

Complexes of yttrium and lanthanide nitrates with a Schiff base, N, N 1 -bis(4-antipyrylmethylidene)ethylenediamine (BAME) having the general formula [Ln(BAME) 2 (NO 3 )](NO 3 ) 2 , where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er have been synthesised and characterised by elemental analyses, molar conductance in non-aqueous solvents, electronic, infrared and proton NMR spectra. BAME acts as a neutral bidentate ligand coordinating through both azomethine nitrogen atoms. One of the nitrate groups is coordinated in a bidentate manner. A coordination number of six may be assigned to the metal ion in these complexes. The covalency parameters evaluated from the solid state electronic spectra suggest weak covalent character of the metal-ligand bond. (author)

Studies on supercritical hydrothermal syntheses of uranium and lanthanide oxide particles and their reaction mechanisms

Science.gov (United States)

Hwang, DongKi; Tsukahara, Takehiko; Tanaka, Kosuke; Osaka, Masahiko; Ikeda, Yasuhisa

2015-11-01

In order to develop preparation method of raw metal oxide particles for low decontaminated MOX fuels by supercritical hydrothermal (SH) treatments, we have investigated behavior of aqueous solutions dissolving U(VI), Ln(III) (Ln: lanthanide = Ce, Pr, Nd, Sm, Tb), Cs(I), and Sr(II) nitrate or chloride compounds under SH conditions (temperature = 400-500 °C, pressure = 30-40 MPa). As a result, it was found that Ln(NO3)3 (Ln = Ce, Pr, Tb) compounds produce LnO2, that Ln(NO3)3 (Ln = Nd, Sm) compounds are hardly converted to their oxides, and that LnCl3 (Ln = Ce, Pr, Nd, Sm, Tb), CsNO3, and Sr(NO3)2 do not form their oxide compounds. Furthermore, HNO2 species were detected in the liquid phase obtained after treating HNO3 aqueous solutions containing Ln(NO3)3 (Ln = Ce, Pr, Tb) under SH conditions, and also NO2 and NO compounds were found to be produced by decomposition of HNO3. From these results, it was proposed that the Ln oxide (LnO2) particles are directly formed with oxidation of Ln(III) to Ln(IV) by HNO3 and HNO2 species in the SH systems. Moreover, the uranyl ions were found to form U3O8 and UO3 depending on the concentration of HNO3. From these results, it is expected that the raw metal oxide particles for low decontaminated MOX fuels are efficiently prepared by the SH method.

A [Cyclentetrakis(methylene)]tetrakis[2-hydroxybenzamide]Ligand That Complexes and Sensitizes Lanthanide(III) Ions

Energy Technology Data Exchange (ETDEWEB)

D' Aleo, Anthony; Xu, Jide; Do, King; Muller, Gilles; Raymond, Kenneth N.

2009-04-30

The synthesis of a cyclen derivative containing four isophthalamide groups (L{sup 1}) is described. The spectroscopic properties of the Ln(III) complexes of L{sup 1} (Ln = Gd, Tb, Yb, Eu) reveal changes of the UV/visible absorption, circular dichroism absorption, luminescence and circularly polarized luminescence properties. It is shown that at least two metal complex species are present in solution, whose relative amounts are pH dependent. When at pH > 8.0, an intense long lived emission is observed (for [L{sup 1}Tb] and [L{sup 1}Yb]) while at pH < 8.0, a weaker, shorter-lived species predominates. Unconventional Ln(III) emitters (Pr, Nd, Sm, Dy and Tm) were sensitized in basic solution, both in the visible and in the near infra-red, to measure the emission of these ions.

Surface shift of the occupied and unoccupied 4f levels of the rare-earth metals

DEFF Research Database (Denmark)

Aldén, Magnus; Johansson, Börje; Skriver, Hans Lomholt

1995-01-01

The surface energy shifts of the occupied and unoccupied 4f levels for the lanthanide metals have been calculated from first principles by means of a Green’s-function technique within the tight-binding linear muffin-tin orbitals method. We use the concept of complete screening to identify...... the occupied and unoccupied 4f energy level shifts as the surface segregation energy of a 4fn-1 and 4fn+1 impurity atom, respectively, in a 4fn host metal. The calculations include both initial- and final-state effects and give values that are considerably lower than those measured on polycrystalline samples...... as well as those found in previous initial-state model calculations. The present theory agrees well with very recent high-resolution, single-crystal film measurements for Gd, Tb, Dy, Ho, Er, Tm, and Lu. We furthermore utilize the unique possibility offered by the lanthanide metals to clarify the roles...

Structure, magnetism, and transport of single-crystalline R NiSi3 (R = Y, Gd-Tm, Lu)

Science.gov (United States)

Arantes, Fabiana R.; Aristizábal-Giraldo, Deisy; Masunaga, Sueli H.; Costa, Fanny N.; Ferreira, Fabio F.; Takabatake, Toshiro; Mendonça-Ferreira, Leticie; Ribeiro, Raquel A.; Avila, Marcos A.

2018-04-01

We report on the physical properties of the intermetallic series R NiSi3 (R =Y , Gd-Tm, Lu). High quality single crystals with platelike morphology were grown using the Sn flux method. X-ray powder diffraction data show that this series crystallizes in the orthorhombic space group Cmmm, and Laue patterns indicate that the b axis remains perpendicular to the plane of the plates. Magnetization measurements show anisotropic antiferromagnetic ground states for R = Gd-Tm with Néel temperatures ranging from TN=2.6 K (TmNiSi3) up to 32.2 K (TbNiSi3), as well as metamagnetic transitions that in some cases appear together with hysteresis (TbNiSi3,DyNiSi3, and HoNiSi3). The easy axis changes from a axis to b axis on going from R = Gd-Ho to R = Er-Tm. All transitions from antiferromagnetic to paramagnetic states are clearly marked by sharp peaks in specific heat as well as in the derivative of resistivity measurements, which show metallic temperature dependence for all compounds and residual values in the range of 1 μ Ω cm . DyNiSi3 has two close phase transitions, while HoNiSi3 presents distinct critical temperatures for applied fields in the a or c directions (10.4 and 6.3 K, respectively), pointing to possible component-specific ordering of the local magnetic moments.

Zero-field splitting in the isoelectronic aqueous Gd(III) and Eu(II) complexes from a first principles analysis

Science.gov (United States)

Khan, S.; Peters, V.; Kowalewski, J.; Odelius, M.

2018-03-01

The zero-field splitting (ZFS) of the ground state octet in aqueous Eu(II) and Gd(III) solutions was investigated through multi- configurational quantum chemical calculations and ab initio molecular dynamics (AIMD) simulations. Investigation of the ZFS of the lanthanide ions is essential to understand the electron spin dynamics and nuclear spin relaxation around paramagnetic ions and consequently the mechanisms underlying applications like magnetic resonance imaging. We found by comparing clusters at identical geometries but different metallic centres that there is not a simple relationship for their ZFS, in spite of the complexes being isoelectronic - each containing 7 unpaired f electrons. Through sampling it was established that inclusion of the first hydration shell has a dominant (over 90 %) influence on the ZFS. Extended sampling of aqueous Gd(III) showed that the 2 nd order spin Hamiltonian formalism is valid and that the rhombic ZFS component is decisive.

The Effect of Tb and Sm Ions on the Photochromic Behavior of Two Spiropyrans of Benzoxazine Series in Solution

Directory of Open Access Journals (Sweden)

Esam Bakeir

2008-01-01

Full Text Available The photochromism of [7′-hydroxy-8′-formyl-3-methyl-4-oxospiro[1,3-benzoxazin-2,2′-[2H-1]benzopyran],SP(I,[7′-hydroxy-8′-formyl-3-benzyl-4-oxospiro[1,3-benzoxazin-2,2′-[2H-1]benzopyran] SP(II and their coordination with Tb3+and Sm3+ ions have been studied in DMF. UV/vis induced-color development due to heterolytic bond cleavage of SP(I and SP(II is greatly influenced by complexation with the lanthanide ions. The irradiation-induced color enhancement due to ring opening and thermal decoloration of the open forms of SP(I, SP(II follows first-order kinetics. Physical characteristics of the studied systems such as colorability and relaxation time of thermal bleaching parameters were determined. Moreover, light-energy transfer-induced luminescence of lanthanide ions via coordination with the two spirobenzoxazines was monitored.

Electronic and Ionic Transport in Ce0.8PrxTb0.2−xO2−δ and Evaluation of Performance as Oxygen Permeation Membranes

DEFF Research Database (Denmark)

Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

2012-01-01

to that of Ce0.9Gd0.1O1.95−δ, and was found to increase with increasing Pr/Tb ratio. The oxide ion mobility in Ce0.8PrxTb0.2−xO2−δ is similar to that in Ce1−2δGd2δO2−δ at the same oxygen vacancy concentration. Based on the measured ionic and electronic conductivities, fluxes through thin film Ce0.8PrxTb0.2−xO2......The electronic conductivity of Ce0.8PrxTb0.2−xO2−δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 – 10−17 at 700–900°C by Hebb-Wagner polarization. The electronic conductivity of all the Ce0.8PrxTb0.2−xO2−δ compositions was significantly enhanced as compared......−δ membranes were calculated. Calculated fluxes exceed 10 Nml min−1 cm−2 under oxyfuel relevant conditions (T = 800°C, aO2,permeate side = 10−3). Hence, in terms of transport properties, these materials are promising for this application. Interference between the ionic and electronic flows has...

Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Feng, Xun [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Liu, Lang [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Wang, Li-Ya, E-mail: wlya@lynu.edu.cn [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang 473601 (China); Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Ng, Seik-Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 80203 (Saudi Arabia)

2013-10-15

A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln{sub 2}(Hdpp){sub 2}(dpp){sub 2}]{sub n}Ln=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H{sub 2}dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1–5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 4+} basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions. - Graphical abstract: A new family of lanthanide-organic frameworks incorporating multi-donor twisted ligand has been fabricated successfully, and has been characterized systematically. The complexes 1–5 are isostructural, and all feather three dimensional (3D) frameworks based on the interconnection of 1D double stride chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 2+} basic carboxylate as secondary building unit (SBU). Display Omitted - Highlights: • New family of lanthanide–organic coordination polymers incorporating multifunctional N-hetrocyclic dicarboxylate ligand has been fabricated. • They have been characterized systematically. • They all feather three dimensional frameworks based on the binuclear moiety of [Ln{sub 2}(Hdpp){sub 2}]{sup 2+}. • The Eu(III) and Dy(III) analogues exhibit intense photoluminescence.

Spectral studies of Lanthanide interactions with membrane surfaces

Energy Technology Data Exchange (ETDEWEB)

Karukstis, K.K.; Kao, M.Y.; Savin, D.A.; Bittker, R.A.; Kaphengst, K.J.; Emetarom, C.M.; Naito, N.R.; Takamoto, D.Y. [Harvey Mudd College, Claremont, CA (United States)

1995-03-23

We have monitored the interactions of the series of trivalent lanthanide cations with the thylakoid membrane surface of spinach chloroplasts using two complementary spectral techniques. Measurements of the fluorescence emission of the extrinsic probe 2-p-toluidinonaphthalene-6-sulfonate (TNS) and the absorbance of the intrinsic chromophore chlorophyll provide two sensitive means of characterizing the dependence of the cation-membrane interaction on the nature of the cation. In these systems, added lanthanide cations adsorb onto the membrane surface to neutralize exposed segments of membrane-embedded protein complexes. The lanthanide-induced charge neutralization increases the proximity of added TNS anion to the membrane surface as evidenced by variations in the TNS fluorescence level and wavelength of maximum emission. Our results reveal a strong dependence of TNS fluorescence parameters on both lanthanide size and total orbital angular momentum L value. Lanthanides with greater charge density (small size and/or low L value) enhance the TNS fluorescence level to a greater extent. A possible origin for the lanthanide-dependent TNS fluorescence levels is suggested in terms of a heterogeneity in the number and type of TNS binding sites. The data are consistent with the proposal that larger lanthanides with smaller enthalpies of hydration induce more significant membrane appression. 59 refs., 9 figs., 2 tabs.

A novel strategy for phosphopeptide enrichment using lanthanide phosphate co-precipitation.

Science.gov (United States)

Mirza, Munazza Raza; Rainer, Matthias; Güzel, Yüksel; Choudhary, Iqbal M; Bonn, Günther K

2012-08-01

Reversible phosphorylation of proteins is a common theme in the regulation of important cellular functions such as growth, metabolism, and differentiation. The comprehensive understanding of biological processes requires the characterization of protein phosphorylation at the molecular level. Although, the number of cellular phosphoproteins is relatively high, the phosphorylated residues themselves are generally of low abundance due to the sub-stoichiometric nature. However, low abundance of phosphopeptides and low degree of phosphorylation typically necessitates isolation and concentration of phosphopeptides prior to mass spectrometric analysis. In this study, we used trivalent lanthanide ions (LaCl(3), CeCl(3), EuCl(3), TbCl(3), HoCl(3), ErCl(3), and TmCl(3)) for phosphopeptide enrichment and cleaning-up. Due to their low solubility product, lanthanide ions form stable complexes with the phosphate groups of phosphopeptides and precipitate out of solution. In a further step, non-phosphorylated compounds can easily be removed by simple centrifugation and washing before mass spectrometric analysis using Matrix-assisted laser desorption/ionisation-time of flight. The precipitation method was applied for the isolation of phosphopeptides from standard proteins such as ovalbumin, α-casein, and β-casein. High enrichment of phosphopeptides could also be achieved for real samples such as fresh milk and egg white. The technology presented here represents an excellent and highly selective tool for phosphopeptide recovery; it is easily applicable and shows several advantages as compared with standard approaches such as TiO(2) or IMAC.

Carbonato-bridged Ni(II)2Ln(III)2 (Ln(III) = Gd(III), Tb(III), Dy(III)) complexes generated by atmospheric CO2 fixation and their single-molecule-magnet behavior: [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH or H2O)Ln(III)(NO3)}2]·solvent [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato].

Science.gov (United States)

Sakamoto, Soichiro; Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Mochida, Naotaka; Ishida, Takayuki; Sunatsuki, Yukinari; Re, Nazzareno

2013-06-17

Atmospheric CO2 fixation of [Ni(II)(3-MeOsaltn)(H2O)2]·2.5H2O [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato], Ln(III)(NO3)3·6H2O, and triethylamine occurred in methanol/acetone, giving a first series of carbonato-bridged Ni(II)2Ln(III)2 complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH)Ln(III)(NO3)}2] (1Gd, 1Tb, and 1Dy). When the reaction was carried out in acetonitrile/water, it gave a second series of complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(H2O)Ln(III)(NO3)}2]·2CH3CN·2H2O (2Gd, 2Tb, and 2Dy). For both series, each Ni(II)2Ln(III)2 structure can be described as two di-μ-phenoxo-bridged Ni(II)Ln(III) binuclear units bridged by two carbonato CO3(2-) units to form a carbonato-bridged (μ4-CO3)2{Ni(II)2Ln(III)2} structure. The high-spin Ni(II) ion has octahedral coordination geometry, and the Ln(III) ion is coordinated by O9 donor atoms from Ni(II)(3-MeOsaltn), bidentate NO3(-), and one and two oxygen atoms of two CO3(2-) ions. The NO3(-) ion for the first series roughly lie on Ln-O(methoxy) bonds and are tilted toward the outside, while for the second series, the two oxygen atoms roughly lie on one of the Ln-O(phenoxy) bonds due to the intramolecular hydrogen bond. The temperature-dependent magnetic susceptibilities indicated a ferromagnetic interaction between the Ni(II) and Ln(III) ions (Ln(III) = Gd(III), Tb(III), Dy(III)) for all of the complexes, with a distinctly different magnetic behavior between the two series in the lowest-temperature region due to the Ln(III)-Ln(III) magnetic interaction and/or different magnetic anisotropies of the Tb(III) or Dy(III) ion. Alternating-current susceptibility measurements under the 0 and 1000 Oe direct-current (dc) bias fields showed no magnetic relaxation for the Ni(II)2Gd(III)2 complexes but exhibited an out-of-phase signal for Ni(II)2Tb(III)2 and Ni(II)2Dy(III)2, indicative of slow relaxation of magnetization. The energy barriers, Δ/kB, for the spin flipping were estimated from the Arrhenius

Luminescent lanthanide reporters: new concepts for use in bioanalytical applications

International Nuclear Information System (INIS)

Vuojola, Johanna; Soukka, Tero

2014-01-01

Lanthanides represent the chemical elements from lanthanum to lutetium. They intrinsically exhibit some very exciting photophysical properties, which can be further enhanced by incorporating the lanthanide ion into organic or inorganic sensitizing structures. A very popular approach is to conjugate the lanthanide ion to an organic chromophore structure forming lanthanide chelates. Another approach, which has quickly gained interest, is to incorporate the lanthanide ions into nanoparticle structures, thus attaining improved specific activity and a large surface area for biomolecule immobilization. Lanthanide-based reporters, when properly shielded from the quenching effects of water, usually express strong luminescence emission, multiple narrow emission lines covering a wide wavelength range, and exceptionally long excited state lifetimes enabling time-gated luminescence detection. Because of these properties, lanthanide-based reporters have found widespread applications in various fields of life. This review focuses on the field of bioanalytical applications. Luminescent lanthanide reporters and assay formats utilizing these reporters pave the way for increasingly sensitive, simple, and easily automated bioanalytical applications. (topical review)

Calcium fluoride based multifunctional nanoparticles for multimodal imaging

Directory of Open Access Journals (Sweden)

Marion Straßer

2017-07-01

Full Text Available New multifunctional nanoparticles (NPs that can be used as contrast agents (CA in different imaging techniques, such as photoluminescence (PL microscopy and magnetic resonance imaging (MRI, open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF2:(Tb3+,Gd3+ NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd3+ ions on the surface, the NPs reduce the MR T1 relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg−1·s−1. Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL−1 was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF2:(Tb3+,Gd3+ NPs are suitable for medical imaging.

The geochemistry and mobility of the lanthanides in marine sediments

International Nuclear Information System (INIS)

Elderfield, H.

1988-07-01

A study has been made to evaluate lanthanide mobility in sediments directly by measuring concentrations of 10 lanthanide elements in sediments and pore waters. Due to the very low concentrations of the lanthanides in sea water relative to marine sediments, evidence of lanthanide mobilization is usually difficult to detect from studies of solid-phase geochemistry. Results show that the lanthanides can be extremely mobile. Concentrations in pore waters up to 100 times sea water concentrations have been measured. The conclusions are tentative but the present data suggest that the lanthanides are mobilized during oxidation of organic-rich sediments and are relocated in part in association with secondary Fe-rich phases. The behaviour of Ce is, predictably, somewhat different from the other lanthanides and may be more mobile as a consequence of its redox chemistry. (author)

Tb{sup 3+}/Eu{sup 3+}: YF{sub 3} nanophase embedded glass ceramics: Structural characterization, tunable luminescence and temperature sensing behavior

Energy Technology Data Exchange (ETDEWEB)

Chen, Daqin, E-mail: dqchen@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018 (China); Wang, Zhongyi; Zhou, Yang [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018 (China); Huang, Ping, E-mail: phuang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on The Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Ji, Zhenguo, E-mail: jizg@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018 (China)

2015-10-15

Tb{sup 3+}/Eu{sup 3+} co-doped transparent bulk glass ceramics containing orthorhombic β-YF{sub 3} nanocrystals were successfully synthesized by melt-quenching and subsequent heating. The partition of the active centers into the YF{sub 3} crystalline lattice was confirmed by elemental mapping in the scanning transmission electron microscope, emission spectra and decay curves. As a consequence, Tb{sup 3+} → Eu{sup 3+} energy transfer was demonstrated to be more efficient in the glass ceramic than in the precursor glass, which resulted in color tunable luminescence by simply modifying Eu{sup 3+} content and induced the linearly temperature-dependent fluorescence intensity ratio between the Tb{sup 3+}: {sup 5}D{sub 4} → {sup 7}F{sub 5} transition and the Eu{sup 3+}: {sup 5}D{sub 0} → {sup 7}F{sub 4} one in the Tb{sup 3+}/Eu{sup 3+} co-doped glass ceramic. It is expected that the investigated glass ceramic might be a promising candidate for solid-state lighting as well as optical temperature sensor. - Highlights: • Lanthanide doped glass ceramics containing YF{sub 3} nanocrystals were fabricated. • Tb{sup 3+} and Eu{sup 3+} dopants were confirmed to incorporate into YF{sub 3} lattice. • Tunable luminescence was realized via Tb{sup 3+} → Eu{sup 3+} energy transfer. • Linearly temperature-dependent fluorescence intensity ratio was detected.

Inorganic pigments doped with tris(pyrazol-1-yl)borate lanthanide complexes: A photoluminescence study

Energy Technology Data Exchange (ETDEWEB)

Gheno, Giulia, E-mail: giulia.gheno@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Bortoluzzi, Marco; Ganzerla, Renzo [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera, Venezia (Italy)

2014-01-15

The inorganic pigments malachite, Egyptian blue, Ercolano blue and chrome yellow have been doped with the neutral homoleptic Ln(III) complex Ln(Tp){sub 3} (Ln=Eu, Tb; Tp=hydrotris(pyrazol-1-yl)borate) in the presence of arabic gum or acrylic emulsion as binders, in order to obtain photoluminescent materials of interest for cultural heritage restoration. The doped pigments have shown emissions associated to f–f transitions in the visible range upon excitation with UV light. Thermal and UV-light ageings have been carried out. In all the cases the photoluminescent behaviour is maintained, but in the cases of acrylic-based paints emission spectra and lifetimes are strongly influenced by thermal treatments. The choice of binder and pigments influences the photoluminescent behaviour of the corresponding film paints. -- Highlights: • Inorganic pigments doped with photoluminescent lanthanide complexes. • Hydrotris(pyrazol-1-yl)borate (Tp) as antenna-ligand for Eu(III) and Tb(III). • Emission associated to f–f transitions upon excitation with UV light. • Photoluminescence of paints influenced by the choice of binder and pigments. • Photoluminescence after ageing depending upon the type of binder.

Modifying the size and uniformity of upconversion Yb/Er:NaGdF4 nanocrystals through alkaline-earth doping.

Science.gov (United States)

Lei, Lei; Chen, Daqin; Huang, Ping; Xu, Ju; Zhang, Rui; Wang, Yuansheng

2013-11-21

NaGdF4 is regarded as an ideal upconversion (UC) host material for lanthanide (Ln(3+)) activators because of its unique crystal structure, high Ln(3+) solubility, low phonon energy and high photochemical stability, and Ln(3+)-doped NaGdF4 UC nanocrystals (NCs) have been widely investigated as bio-imaging and magnetic resonance imaging agents recently. To realize their practical applications, controlling the size and uniformity of the monodisperse Ln(3+)-doped NaGdF4 UC NCs is highly desired. Unlike the routine routes by finely adjusting the multiple experimental parameters, herein we provide a facile and straightforward strategy to modify the size and uniformity of NaGdF4 NCs via alkaline-earth doping for the first time. With the increase of alkaline-earth doping content, the size of NaGdF4 NCs increases gradually, while the size-uniformity is still retained. We attribute this "focusing" of size distribution to the diffusion controlled growth of NaGdF4 NCs induced by alkaline-earth doping. Importantly, adopting the Ca(2+)-doped Yb/Er:NaGdF4 NCs as cores, the complete Ca/Yb/Er:NaGdF4@NaYF4 core-shell particles with excellent size-uniformity can be easily achieved. However, when taking the Yb/Er:NaGdF4 NCs without Ca(2+) doping as cores, they could not be perfectly covered by NaYF4 shells, and the obtained products are non-uniform in size. As a result, the UC emission intensity of the complete core-shell NCs increases by about 30 times in comparison with that of the cores, owing to the effective surface passivation of the Ca(2+)-doped cores and therefore protection of Er(3+) in the cores from the non-radiative decay caused by surface defects, whereas the UC intensity of the incomplete core-shell NCs is enhanced by only 3 times.

Chiral Silver-Lanthanide Metal-Organic Frameworks Comprised of One-Dimensional Triple Right-Handed Helical Chains Based on [Ln7(μ3-OH)8]13+ Clusters.

Science.gov (United States)

Guo, Yan; Zhang, Lijuan; Muhammad, Nadeem; Xu, Yan; Zhou, Yunshan; Tang, Fang; Yang, Shaowei

2018-02-05

Three new isostructural chiral silver-lanthanide heterometal-organic frameworks [Ag 3 Ln 7 (μ 3 -OH) 8 (bpdc) 6 (NO 3 ) 3 (H 2 O) 6 ](NO 3 )·2H 2 O [Ln = Eu (1), Tb (2, Sm (3); H 2 bpdc = 2,2'-bipyridine-3,3'-dicarboxylic acid] based on heptanuclear lanthanide clusters [Ln 7 (μ 3 -OH) 8 ] 13+ comprised of one-dimensional triple right-handed helical chains were hydrothermally synthesized. Various means such as UV-vis spectroscopy, IR spectroscopy, elemental analysis, powder X-ray diffraction, and thermogravimetric/differential thermal analysis were used to characterize the compounds, wherein compound 3 was crystallographically characterized. In the structure of compound 3, eight μ 3 -OH - groups link seven Sm 3+ ions, forming a heptanuclear cluster, [Sm 7 (μ 3 -OH) 8 ] 13+ , and the adjacent [Sm 7 (μ 3 -OH) 8 ] 13+ clusters are linked by the carboxylic groups of bpdc 2- ligands, leading to the formation of a one-dimensional triple right-handed helical chain. The adjacent triple right-handed helical chains are further joined together by coordinating the pyridyl N atoms of the bpdc 2- ligands with Ag + , resulting in a chiral three-dimensional silver(I)-lanthanide(III) heterometal-organic framework with one-dimensional channels wherein NO 3 - anions and crystal lattice H 2 O molecules are trapped. The compounds were studied systematically with respect to their photoluminescence properties and energy-transfer mechanism, and it was found that H 2 bpdc (the energy level for the triplet states of the ligand H 2 bpdc is 21505 cm -1 ) can sensitize Eu 3+ luminescence more effectively than Tb 3+ and Sm 3+ luminescence because of effective energy transfer from bpdc 2- to Eu 3+ under excitation in compound 1.

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

Science.gov (United States)

Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

2015-01-01

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO4 2 - anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic-inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.

Strong blue and white photoluminescence emission of BaZrO{sub 3} undoped and lanthanide doped phosphor for light emitting diodes application

Energy Technology Data Exchange (ETDEWEB)

Romero, V.H. [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Velazquez-Salazar, J.J. [Department of Physics and Astronomy, The University of Texas at San Antonio One UTSA Circle, San Antonio TX 78249 (United States)

2012-12-15

In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for undoped BaZrO{sub 3} observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm{sup 3+} ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb{sup 3+} and Eu{sup 3+} ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides. - Graphical abstract: Strong blue emission from undoped BaZrO{sub 3} phosphor and white light emission by doping with Tb{sup 3+} (green) and Eu{sup 3+} (red) after 266 nm excitation. Highlights: Black-Right-Pointing-Pointer Blue emission from BaZrO{sub 3} phosphor. Black-Right-Pointing-Pointer Blue emission enhanced with Tm{sup 3+}. Black-Right-Pointing-Pointer White light from BaZrO{sup 3+} phosphor.

Glass-ceramic nuclear waste forms obtained by crystallization of SiO 2-Al 2O 3-CaO-ZrO 2-TiO 2 glasses containing lanthanides (Ce, Nd, Eu, Gd, Yb) and actinides (Th): Study of the crystallization from the surface

Science.gov (United States)

Loiseau, P.; Caurant, D.

2010-07-01

Glass-ceramic materials containing zirconolite (nominally CaZrTi 2O 7) crystals in their bulk can be envisaged as potential waste forms for minor actinides (Np, Am, Cm) and Pu immobilization. In this study such matrices are synthesized by crystallization of SiO 2-Al 2O 3-CaO-ZrO 2-TiO 2 glasses containing lanthanides (Ce, Nd, Eu, Gd, Yb) and actinides (Th) as surrogates. A thin partially crystallized layer containing titanite and anorthite (nominally CaTiSiO 5 and CaAl 2Si 2O 8, respectively) growing from glass surface is also observed. The effect of the nature and concentration of surrogates on the structure, the microstructure and the composition of the crystals formed in the surface layer is presented in this paper. Titanite is the only crystalline phase able to significantly incorporate trivalent lanthanides whereas ThO 2 precipitates in the layer. The crystal growth thermal treatment duration (2-300 h) at high temperature (1050-1200 °C) is shown to strongly affect glass-ceramics microstructure. For the system studied in this paper, it appears that zirconolite is not thermodynamically stable in comparison with titanite growing form glass surface. Nevertheless, for kinetic reasons, such transformation (i.e. zirconolite disappearance to the benefit of titanite) is not expected to occur during interim storage and disposal of the glass-ceramic waste forms because their temperature will never exceed a few hundred degrees.

Semiempirical and DFT computations of the influence of Tb(III) dopant on unit cell dimensions of cerium(III) fluoride.

Science.gov (United States)

Shyichuk, Andrii; Runowski, Marcin; Lis, Stefan; Kaczkowski, Jakub; Jezierski, Andrzej

2015-01-30

Several computational methods, both semiempirical and ab initio, were used to study the influence of the amount of dopant on crystal cell dimensions of CeF3 doped with Tb(3+) ions (CeF3 :Tb(3+) ). AM1, RM1, PM3, PM6, and PM7 semiempirical parameterization models were used, while the Sparkle model was used to represent the lanthanide cations in all cases. Ab initio calculations were performed by means of GGA+U/PBE projector augmented wave density functional theory. The computational results agree well with the experimental data. According to both computation and experiment, the crystal cell parameters undergo a linear decrease with increasing amount of the dopant. The computations performed using Sparkle/PM3 and DFT methods resulted in the best agreement with the experiment with the average deviation of about 1% in both cases. Typical Sparkle/PM3 computation on a 2×2×2 supercell of CeF3:Tb3+ lasted about two orders of magnitude shorter than the DFT computation concerning a unit cell of this material. © 2014 Wiley Periodicals, Inc.

The Gd14Ag51 structure type and its relation to some complex amalgam structures

International Nuclear Information System (INIS)

Tambornino, Frank; Sappl, Jonathan; Hoch, Constantin

2015-01-01

Highlights: • The Gd 14 Ag 51 structure type has been revisited on the basis of single crystal diffraction data. • Symmetry analysis from electron density and TEM shows the space group P6/m to be true. • Gd 14 Ag 51 shows good metallic behaviour. • Structure relations to alkali, alkaline-earth and rare-earth metal amalgams can be established. • Complexity values for the RE 14 Ag 51 structure family were calculated. - Abstract: A plethora of binary and ternary intermetallic compounds has been assigned to the Gd 14 Ag 51 structure type, crystallising in the hexagonal system (space group P6/m, a = 1264.30(18) pm, c = 933.58(11) pm for Gd 14 Ag 51 ). Starting in the late 1960s, much work has been invested in the structural elucidation of these crystal structures. However, reliable single crystal data are scarce, and most structure type assignments have been performed merely on the basis of powder data. We have redetermined four representatives of the binary RE 14 Ag 51 structure type (RE = Y, Ce, Gd, Tb) with modern high-precision single crystal X-ray methods. The assignment of the Gd 14 Ag 51 structure type to space group P6/m was additionally verified by careful analysis of high resolution transmission electron micrographs. We emphasise the close relation of the Gd 14 Ag 51 structure type to the structures of some recently described amalgams of similar composition focussing on disorder phenomena and structural complexity. Furthermore, we provide detailed information on synthesis as well as electrical and magnetic properties for Gd 14 Ag 51 , the parent compound of this structure family

NMR study of structure of lanthanide complexes in solution

International Nuclear Information System (INIS)

Choppin, G.R.

1976-01-01

The diagnostic value PMR studies of diamagnetic lanthanide complexes to define the nature of the species in the lanthanide-pyruvate system is discussed. The use of NMR spectra of both diamagnetic and paramagnetic lanthanide complexes to obtain detailed structural information is reviewed

Radiochemical separation of Tb-149 after tandem accelerator production

International Nuclear Information System (INIS)

Sarkar, S.R.

1996-01-01

Full text: Terbium-149 is produced by the heavy ion induced reaction of the type 142 Nd( 12 C,5n) 149 Dy→ 149 Tb. This work concerns the separation of terbium from neodymium target, and other lanthanides produced by secondary reactions on neodymium target. Firstly, anion-exchange separation is carried out at room temperature using acid-alcohol media (90% methanol-10% 5M nitric acid) as eluent. But the separation is not satisfactory. To achieve satisfactory separation, cation exchange separation is performed under pressure at room temperature using 0.1 6M α-hydroxyisobutyric acid of pH 5 as eluent. The pressure is exerted from a nitrogen gas cylinder. The simplicity and efficacy of this method for the separation of terbium are discussed in comparison with the commercially available high performance liquid chromatography system

Lanthanides, thorium, iodine in terrestrail invertebrates

International Nuclear Information System (INIS)

Zhulidov, A.V.; Pokarzhevskij, A.D.; Katargin, N.V.; AN SSSR, Moscow