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Sample records for paramagnetic fluorine-labelled lanthanide

  1. Design principles and theory of paramagnetic fluorine-labelled lanthanide complexes as probes for (19)F magnetic resonance: a proof-of-concept study.

    Science.gov (United States)

    Chalmers, Kirsten H; De Luca, Elena; Hogg, Naomi H M; Kenwright, Alan M; Kuprov, Ilya; Parker, David; Botta, Mauro; Wilson, J Ian; Blamire, Andrew M

    2010-01-04

    The synthesis and spectroscopic properties of a series of CF(3)-labelled lanthanide(III) complexes (Ln=Gd, Tb, Dy, Ho, Er, Tm) with amide-substituted ligands based on 1,4,7,10-tetraazacyclododecane are described. The theoretical contributions of the (19)F magnetic relaxation processes in these systems are critically assessed and selected volumetric plots are presented. These plots allow an accurate estimation of the increase in the rates of longitudinal and transverse relaxation as a function of the distance between the Ln(III) ion and the fluorine nucleus, the applied magnetic field, and the re-rotational correlation time of the complex, for a given Ln(III) ion. Selected complexes exhibit pH-dependent chemical shift behaviour, and a pK(a) of 7.0 was determined in one example based on the holmium complex of an ortho-cyano DO3A-monoamide ligand, which allowed the pH to be assessed by measuring the difference in chemical shift (varying by over 14 ppm) between two (19)F resonances. Relaxation analyses of variable-temperature and variable-field (19)F, (17)O and (1)H NMR spectroscopy experiments are reported, aided by identification of salient low-energy conformers by using density functional theory. The study of fluorine relaxation rates, over a field range of 4.7 to 16.5 T allowed precise computation of the distance between the Ln(III) ion and the CF(3) reporter group by using global fitting methods. The sensitivity benefits of using such paramagnetic fluorinated probes in (19)F NMR spectroscopic studies are quantified in preliminary spectroscopic and imaging experiments with respect to a diamagnetic yttrium(III) analogue.

  2. An NMR strategy for fragment-based ligand screening utilizing a paramagnetic lanthanide probe

    International Nuclear Information System (INIS)

    Saio, Tomohide; Ogura, Kenji; Shimizu, Kazumi; Yokochi, Masashi; Burke, Terrence R.; Inagaki, Fuyuhiko

    2011-01-01

    A nuclear magnetic resonance-based ligand screening strategy utilizing a paramagnetic lanthanide probe is presented. By fixing a paramagnetic lanthanide ion to a target protein, a pseudo-contact shift (PCS) and a paramagnetic relaxation enhancement (PRE) can be observed for both the target protein and its bound ligand. Based on PRE and PCS information, the bound ligand is then screened from the compound library and the structure of the ligand–protein complex is determined. PRE is an isotropic paramagnetic effect observed within 30 Å from the lanthanide ion, and is utilized for the ligand screening in the present study. PCS is an anisotropic paramagnetic effect providing long-range (∼40 Å) distance and angular information on the observed nuclei relative to the paramagnetic lanthanide ion, and utilized for the structure determination of the ligand–protein complex. Since a two-point anchored lanthanide-binding peptide tag is utilized for fixing the lanthanide ion to the target protein, this screening method can be generally applied to non-metal-binding proteins. The usefulness of this strategy was demonstrated in the case of the growth factor receptor-bound protein 2 (Grb2) Src homology 2 (SH2) domain and its low- and high-affinity ligands.

  3. Two-point anchoring of a lanthanide-binding peptide to a target protein enhances the paramagnetic anisotropic effect

    International Nuclear Information System (INIS)

    Saio, Tomohide; Ogura, Kenji; Yokochi, Masashi; Kobashigawa, Yoshihiro; Inagaki, Fuyuhiko

    2009-01-01

    Paramagnetic lanthanide ions fixed in a protein frame induce several paramagnetic effects such as pseudo-contact shifts and residual dipolar couplings. These effects provide long-range distance and angular information for proteins and, therefore, are valuable in protein structural analysis. However, until recently this approach had been restricted to metal-binding proteins, but now it has become applicable to non-metalloproteins through the use of a lanthanide-binding tag. Here we report a lanthanide-binding peptide tag anchored via two points to the target proteins. Compared to conventional single-point attached tags, the two-point linked tag provides two to threefold stronger anisotropic effects. Though there is slight residual mobility of the lanthanide-binding tag, the present tag provides a higher anisotropic paramagnetic effect

  4. High gradient magnetic separation of upconverting lanthanide nanophosphors based on their intrinsic paramagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Arppe, Riikka, E-mail: riikka.arppe@utu.fi; Salovaara, Oskari; Mattsson, Leena; Lahtinen, Satu; Valta, Timo; Riuttamaeki, Terhi; Soukka, Tero [University of Turku, Department of Biotechnology (Finland)

    2013-09-15

    Photon upconverting nanophosphors (UCNPs) have the unique luminescent property of converting low-energy infrared light into visible emission which can be widely utilized in nanoreporter and imaging applications. For the use as reporters in these applications, the UCNPs must undergo a series of surface modification and bioconjugation reactions. Efficient purification methods are required to remove the excess reagents and biomolecules from the nanophosphor solution after each step to yield highly responsive reporters for sensitive bioanalytical assays. However, as the particle size of the UCNPs approaches the size of biomolecules, the handling of these reporters becomes cumbersome with traditional purification methods such as centrifugation. Here we introduce a novel approach for purification of bioconjugated 32-nm NaYF{sub 4}: Yb{sup 3+}, Er{sup 3+}-nanophosphors from excess unbound biomolecules utilizing high gradient magnetic separation (HGMS)-system constructed from permanent super magnets which produce magnetic gradients in a magnetizable steel wool matrix amplifying the magnetic field. The non-magnetic biomolecules flowed straight through the magnetized HGMS-column while the UCNPs were eluted only after the magnetic field was removed. In the UCNPs the luminescent centers, i.e., lanthanide-ion dopants are responsible for the strong upconversion luminescence, but in addition they are also paramagnetic. In this study we have shown that the presence of these weakly paramagnetic luminescent lanthanides actually also enables the use of HGMS to capture the UCNPs without incorporating additional optically inactive magnetic core into them.

  5. High gradient magnetic separation of upconverting lanthanide nanophosphors based on their intrinsic paramagnetism

    International Nuclear Information System (INIS)

    Arppe, Riikka; Salovaara, Oskari; Mattsson, Leena; Lahtinen, Satu; Valta, Timo; Riuttamäki, Terhi; Soukka, Tero

    2013-01-01

    Photon upconverting nanophosphors (UCNPs) have the unique luminescent property of converting low-energy infrared light into visible emission which can be widely utilized in nanoreporter and imaging applications. For the use as reporters in these applications, the UCNPs must undergo a series of surface modification and bioconjugation reactions. Efficient purification methods are required to remove the excess reagents and biomolecules from the nanophosphor solution after each step to yield highly responsive reporters for sensitive bioanalytical assays. However, as the particle size of the UCNPs approaches the size of biomolecules, the handling of these reporters becomes cumbersome with traditional purification methods such as centrifugation. Here we introduce a novel approach for purification of bioconjugated 32-nm NaYF 4 : Yb 3+ , Er 3+ -nanophosphors from excess unbound biomolecules utilizing high gradient magnetic separation (HGMS)-system constructed from permanent super magnets which produce magnetic gradients in a magnetizable steel wool matrix amplifying the magnetic field. The non-magnetic biomolecules flowed straight through the magnetized HGMS-column while the UCNPs were eluted only after the magnetic field was removed. In the UCNPs the luminescent centers, i.e., lanthanide-ion dopants are responsible for the strong upconversion luminescence, but in addition they are also paramagnetic. In this study we have shown that the presence of these weakly paramagnetic luminescent lanthanides actually also enables the use of HGMS to capture the UCNPs without incorporating additional optically inactive magnetic core into them

  6. Investigation of lanthanide ions and other paramagnetic impurities in natural fluorite by electron paramagnetic resonance: examples of application to mining exploration and geochemistry

    International Nuclear Information System (INIS)

    Chatagnon, B.

    1981-01-01

    This research thesis reports the application to geology, and more particularly to geochemistry and mining exploration, of a physical method: the electron paramagnetic resonance (EPR). After a report of a bibliographical investigation on mineralogy and geochemistry of fluorite and lanthanides, as well as on paramagnetic centres observed by physicists in synthetic fluorite, the author reports an experimental work, and describes two examples of application of EPR: firstly, the exploration of radioactive ores, and secondly, with the joint use of neutron activation analysis, the characterization of the redox status of the hydrothermal solution which is at the origin of fluorinated mineralisation

  7. 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.

  8. A minor conformation of a lanthanide tag on adenylate kinase characterized by paramagnetic relaxation dispersion NMR spectroscopy

    International Nuclear Information System (INIS)

    Hass, Mathias A. S.; Liu, Wei-Min; Agafonov, Roman V.; Otten, Renee; Phung, Lien A.; Schilder, Jesika T.; Kern, Dorothee; Ubbink, Marcellus

    2015-01-01

    NMR relaxation dispersion techniques provide a powerful method to study protein dynamics by characterizing lowly populated conformations that are in dynamic exchange with the major state. Paramagnetic NMR is a versatile tool for investigating the structures and dynamics of proteins. These two techniques were combined here to measure accurate and precise pseudocontact shifts of a lowly populated conformation. This method delivers valuable long-range structural restraints for higher energy conformations of macromolecules in solution. Another advantage of combining pseudocontact shifts with relaxation dispersion is the increase in the amplitude of dispersion profiles. Lowly populated states are often involved in functional processes, such as enzyme catalysis, signaling, and protein/protein interactions. The presented results also unveil a critical problem with the lanthanide tag used to generate paramagnetic relaxation dispersion effects in proteins, namely that the motions of the tag can interfere severely with the observation of protein dynamics. The two-point attached CLaNP-5 lanthanide tag was linked to adenylate kinase. From the paramagnetic relaxation dispersion only motion of the tag is observed. The data can be described accurately by a two-state model in which the protein-attached tag undergoes a 23° tilting motion on a timescale of milliseconds. The work demonstrates the large potential of paramagnetic relaxation dispersion and the challenge to improve current tags to minimize relaxation dispersion from tag movements

  9. Subnanodimensional thermometrical NMR-sensors on the basis of lanthanide(III) paramagnetic complexes with EDTA for temperature control in aqueous media and magnetoresonance tomography

    International Nuclear Information System (INIS)

    Babajlov, S.P.

    2008-01-01

    It is proposed that temperature dependence of paramagnetic lanthanide-induced shifts (LIS) in NMR spectra on nuclei of EDTA type synthetic organic complexes in kinetically unstable compounds with paramagnetic lanthanide(III) cations is used for ascertaining the temperature of samples placed directly into a NMR spectrometer and formed on the basis of aqueous solutions of diverse chemical substances. It was revealed that complex [Ho III (EDTA)] can be used as an internal or an external thermometric NMR-sensor. For identification and control of temperature in a sample one can make use of LIS for individual signals from CH 2 groups (taken in relation to water or inner DCC standard signals). A higher temperature measurement accuracy (≤0.08 K) is attained by using LIS difference corresponding to the relevant nonequivalent CH 2 groups [ru

  10. 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

  11. Lanthanide paramagnetic probes for NMR spectroscopic studies of fast molecular conformational dynamics and temperature control. Effective six-site proton exchange in 18-crown-6 by exchange spectroscopy.

    Science.gov (United States)

    Babailov, Sergey P

    2012-02-06

    (1)H and (13)C NMR measurements are reported for the CDCl(3) and CD(2)Cl(2) solutions of [La(18-crown-6)(NO(3))(3)] (I), [Pr(18-crown-6) (NO(3))(3)] (II), [Ce(18-crown-6)(NO(3))(3)] (III), and [Nd(18-crown-6)(NO(3))(3)] (IV) complexes. Temperature dependencies of the (1)H NMR spectra of paramagnetic II-IV have been analyzed using the dynamic NMR (DNMR) methods for six-site exchange. Two types of conformational dynamic processes were identified (the first one is conditioned by interconversion of complex enantiomeric forms and pseudorotation of a macrocycle molecule upon the C(2) symmetry axis; the second one is conditioned by macrocycle molecule inversion). Application of exchange spectroscopy (2D-EXSY) of DNMR for investigation of this dynamic system (II-IV) simplifies the assignment of the NMR signals and represents the first experimental study of multisite exchange. In the present work, the methodology of paramagnetic 4f (Ce, Pr, and Nd) probe applications for the study of free-energy, enthalpy, and entropy changes in chemical exchange processes, as well as the advantages of this method in a comparison with DNMR studies of diamagnetic substances, is discussed. In particular, as a result of paramagnetic chemical shifts in 4f complexes, the range of measurable rate constants expands considerably compared to the analogous range in diamagnetic compounds. Coordination compounds investigated in the paper represent new types of thermometric NMR sensors and lanthanide paramagnetic probes for in situ temperature control in solution.

  12. Thermometric nanosize NMR-sensors for temperature determination in weakly polar non-aqueous media on the base of ion pairs of paramagnetic complexes of lanthanides(III)

    International Nuclear Information System (INIS)

    Babajlov, S.P.

    2008-01-01

    For temperature determination in solutions it is suggested that the temperature dependence of the paramagnetic lanthanide-induced shifts (LIS) in the NMR spectra on the ligand nuclei be used for [Ln(PTA) 2 (18-crown-6)] + [Ln(PTA) 4 ] - complex ion pairs formed in CCl 4 , CDCl 3 , CD 2 Cl 2 , CD 3 C 6 D 5 , and C 2 D 3 N type low-polar solvents (Ln = La, Ce, Pr, Nd, Eu; PTA is the pivalyltrifluoroacetonate anion). It was found experimentally that the [Ln(PTA) 2 (18-crown-6)] + complex cation molecules (Ln = Ce and Pr) proved most suitable for use as nanosized (∼1.1 nm) probes for temperature determinations in nonaqueous solutions. A linear dependence of the LIS on the 1 H nuclei of different groups and the difference between the LIS corresponding to the CH 2 groups of the 18-crown-6 molecules and the CH groups of the PTA anions on the reciprocal temperature (1/T) was found. The LIS of the individual signals of different groups in Ln paramagnetic complexes (relative to the signals of the diamagnetic analogs, e.g., La or Lu) may be used for temperature control in the sample, although the temperature measurement error is smaller (≤0.04 K) when the difference between the LIS of the CH 2 and CH groups is used. Due to the high thermodynamic and kinetic stability combined with small sizes of [Ln(PTA) 2 (18-crown-6)] + [Ln(PTA) 4 ] - molecules in nonaqueous solutions, these compounds may be used as thermometric NMR sensors directly in reaction media for in situ control over temperature [ru

  13. 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

  14. Nucleophilic Fluorination Reactions in Novel Reaction Media for 18F-Fluorine Labeling Method

    International Nuclear Information System (INIS)

    Kim, Dong Wook; Jeong, Hwan Jeong; Lim, Seok Tae; Sohn, Myung Hee

    2009-01-01

    Noninvasive imaging of molecular and biological processes in living subjects with positron emission tomography (PET) provides exciting opportunities to monitor metabolism and detect diseases in humans. Measuring these processes with PET requires the preparation of specific molecular imaging probes labeled with 18F-fluorine. In this review we describe recent methods and novel trends for the introduction of 18 F-fluorine into molecules which in turn are intended to serve as imaging agents for PET study. Nucleophilic 18 F-fluorination of some halo- and mesyloxyalkanes to the corresponding 18 F-fluoroalkanes with 18 F-fluoride obtained from an 18 O(p,n) 18 F reaction, using novel reaction media system such as an ionic liquidor tert-alcohol, has been studied as a new method for 18 F-fluorine labeling. Ionic liquid method is rapid and particularly convenient because 18 F-fluoride in H 2 O can be added directly to the reaction media, obviating the careful drying that is typically required for currently used radiofluorination methods. The nonpolar protic tert-alcohol enhances the nucleophilicity of the fluoride ion dramatically in the absence of any kind of catalyst, greatly increasing the rate of the nucleophilic fluorination and reducing formation of byproducts compared with conventional methods using dipolar aprotic solvents. The great efficacy of this method is a particular advantage in labeling radiopharmaceuticals with 18 F-fluorine for PET imaging, and it is illustrated by the synthesis of 18 F-fluoride radiolabeled molecular imaging probes, such as 18 F-FDG, 18 F-FLT, 18 F-FP-CIT, and 18 F-FMISO, in high yield and purity and in shorter times compared to conventional syntheses

  15. 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.

  16. 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.

  17. 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.)

  18. Electron paramagnetic resonance

    CERN Document Server

    Al'tshuler, S A

    2013-01-01

    Electron Paramagnetic Resonance is a comprehensive text on the field of electron paramagnetic resonance, covering both the theoretical background and the results of experiment. This book is composed of eight chapters that cover theoretical materials and experimental data on ionic crystals, since these are the materials that have been most extensively studied by the methods of paramagnetic resonance. The opening chapters provide an introduction to the basic principles of electron paramagnetic resonance and the methods of its measurement. The next chapters are devoted to the theory of spectra an

  19. Handbook on the physics and chemistry of rare earths: Volume 19: Lanthanides/Actinides: Physics, 2

    International Nuclear Information System (INIS)

    Gschneidner, Karl A.; Eyring, LeRoy; Choppin, G.R.; Lander, G.H.

    1994-01-01

    This handbook comprises five chapters on the lanthanide and actinide materials. In the first chapter the inelastic neutron scattering behaviors of the lanthanides and actinides are compared. In the next chapter the focus is on neutron scattering by heavy fermion single crystal materials, including metallic materials with a paramagnetic ground state, superconductors, metallic and semiconducting antiferromagnets and nearly insulating paramagnets. In chapter three a comprehensive review of intermediate valence and heavy fermions in a wide variety of lanthanide and actinide compounds is given, ranging from metallic to insulating materials. In chapter four two issues on the high pressure behaviours of anomalous cerium, ytterbium and uranium compounds are dealt with. In the final chapter an extensive review is given the thermodynamic properties of lanthanide and actinide metallic systems

  20. 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.

  1. 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.

  2. 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...

  3. 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

  4. Cys-Ph-TAHA: a lanthanide binding tag for RDC and PCS enhanced protein NMR

    NARCIS (Netherlands)

    Peters, Fabian; Maestre-Martinez, M.; Leonov, A.; Kovacic, L.; Becker, S.; Boelens, R.; Griesinger, C.

    2011-01-01

    Here we present Cys-Ph-TAHA, a new nonadentate lanthanide tag for the paramagnetic labelling of proteins. The tag can be easily synthesized and is stereochemically homogenous over a wide range of temperatures, yielding NMR spectra with a single set of peaks. Bound to ubiquitin, it induced large

  5. Levitation in paramagnetic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, P.A. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland)]. E-mail: pdunne2@tcd.ie; Hilton, J. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland); Coey, J.M.D. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland)

    2007-09-15

    Magnetic levitation of diamagnetic and paramagnetic substances in a paramagnetic liquid is explored. Materials ranging from graphite to tin and copper can be made to float at ambient temperature in concentrated solutions of dysprosium nitrate, when an electromagnet or four-block permanent magnet array is used to produce a gradient field. Simulations illustrate the stable regions for levitation above the permanent magnets; and a novel eight-block configuration is proposed, which allows denser materials such as gold or lead to be levitated.

  6. Levitation in paramagnetic liquids

    International Nuclear Information System (INIS)

    Dunne, P.A.; Hilton, J.; Coey, J.M.D.

    2007-01-01

    Magnetic levitation of diamagnetic and paramagnetic substances in a paramagnetic liquid is explored. Materials ranging from graphite to tin and copper can be made to float at ambient temperature in concentrated solutions of dysprosium nitrate, when an electromagnet or four-block permanent magnet array is used to produce a gradient field. Simulations illustrate the stable regions for levitation above the permanent magnets; and a novel eight-block configuration is proposed, which allows denser materials such as gold or lead to be levitated

  7. Electron Paramagnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Electron Paramagnetic Resonance Spectroscopy: Biological Applications. B G Hegde. General Article Volume 20 Issue 11 November 2015 pp 1017-1032. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the ...

  9. Demonstrating Paramagnetism Using Liquid Nitrogen.

    Science.gov (United States)

    Simmonds, Ray; And Others

    1994-01-01

    Describes how liquid nitrogen is attracted to the poles of neodymium magnets. Nitrogen is not paramagnetic, so the attraction suggests that the liquid nitrogen contains a small amount of oxygen, which causes the paramagnetism. (MVL)

  10. 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.

  11. Paramagnetic contrast material

    International Nuclear Information System (INIS)

    McNamara, M.T.

    1987-01-01

    Paramagnetic contrast materials have certainly demonstrated clinical utility in a variety of organ systems for improved detection of various neoplastic, inflammatory, infectious, and physiologic abnormalities. Although the more commonly employed extracellular agents, such as Gd-DTPA, have been quite safe and useful, particularly in the CNS, it is almost certain that other substances will achieve more success in various other organs, such as iron oxides in the reticuloendothelial system and persisting extracellular agents in the cardiovascular system. Finally, as MRI technology continues to evolve, producing such exciting new sequences as gradient-echo fast scans, the roles of currently existing and newly discovered paramagnetic pharmaceuticals must be continuously reevaluated both to obtain maximum clinical benefit and to guide the search for newer agents that may further optimize the diagnostic efficacy of MRI

  12. 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).

  13. 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).

  14. 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.

  15. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  16. 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....

  17. 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)

  18. Valencies of the lanthanides

    OpenAIRE

    Johnson, David A.; Nelson, Peter G.

    2018-01-01

    The valencies of the lanthanides vary more than was once thought. In addition to valencies associated with a half-full shell, there are valencies associated with a quarter- and three-quarter-full shell. This can be explained on the basis of Slater’s theory of many-electron atoms. The same theory explains the variation in complexing constants in the trivalent state (the “tetrad effect”). Valency in metallic and organometallic compounds is also discussed.

  19. Stable and rigid DTPA-like paramagnetic tags suitable for in vitro and in situ protein NMR analysis.

    Science.gov (United States)

    Chen, Jia-Liang; Zhao, Yu; Gong, Yan-Jun; Pan, Bin-Bin; Wang, Xiao; Su, Xun-Cheng

    2018-02-01

    Organic synthesis of a ligand with high binding affinities for paramagnetic lanthanide ions is an effective way of generating paramagnetic effects on proteins. These paramagnetic effects manifested in high-resolution NMR spectroscopy are valuable dynamic and structural restraints of proteins and protein-ligand complexes. A paramagnetic tag generally contains a metal chelating moiety and a reactive group for protein modification. Herein we report two new DTPA-like tags, 4PS-PyDTTA and 4PS-6M-PyDTTA that can be site-specifically attached to a protein with a stable thioether bond. Both protein-tag adducts form stable lanthanide complexes, of which the binding affinities and paramagnetic tensors are tunable with respect to the 6-methyl group in pyridine. Paramagnetic relaxation enhancement (PRE) effects of Gd(III) complex on protein-tag adducts were evaluated in comparison with pseudocontact shift (PCS), and the results indicated that both 4PS-PyDTTA and 4PS-6M-PyDTTA tags are rigid and present high-quality PREs that are crucially important in elucidation of the dynamics and interactions of proteins and protein-ligand complexes. We also show that these two tags are suitable for in-situ protein NMR analysis.

  20. 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.)

  1. Lanthanide Cofactors for Triphosphorylation Ribozymes

    Science.gov (United States)

    Sweeney, K. J.; Müller, U. F.

    2017-07-01

    RNA world organisms could have used trimetaphosphate as energy source for thermodynamically unfavorable RNA polymerization. Using in vitro selection we show here that Lanthanides can serve as cofactors for ribozyme-catalyzed RNA triphosphorylation.

  2. Lanthanide/Actinide Opacities

    Science.gov (United States)

    Hungerford, Aimee; Fontes, Christopher J.

    2018-06-01

    Gravitational wave observations benefit from accompanying electromagnetic signals in order to accurately determine the sky positions of the sources. The ejecta of neutron star mergers are expected to produce such electromagnetic transients, called macronovae (e.g. the recent and unprecedented observation of GW170817). Characteristics of the ejecta include large velocity gradients and the presence of heavy r-process elements, which pose significant challenges to the accurate calculation of radiative opacities and radiation transport. Opacities include a dense forest of bound-bound features arising from near-neutral lanthanide and actinide elements. Here we present an overview of current theoretical opacity determinations that are used by neutron star merger light curve modelers. We will touch on atomic physics and plasma modeling codes that are used to generate these opacities, as well as the limited body of laboratory experiments that may serve as points of validation for these complex atomic physics calculations.

  3. Use of lanthanide catalysts in air electrodes

    International Nuclear Information System (INIS)

    Souza Parente, L.T. de

    1982-01-01

    A review on the lanthanide catalysts suitable for the reduction catalysis of oxygen in air electrodes is presented. The kinds of lanthanide indicated to be used as catalysts of oxygen reduction are shown. (A.R.H.) [pt

  4. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  5. The best and the brightest: exploiting tryptophan-sensitized Tb(3+) luminescence to engineer lanthanide-binding tags.

    Science.gov (United States)

    Martin, Langdon J; Imperiali, Barbara

    2015-01-01

    Consider the lanthanide metals, comprising lanthanum through lutetium. Lanthanides form stable cations with a +3 charge, and these ions exhibit a variety of useful physical properties (long-lifetime luminescence, paramagnetism, anomalous X-ray scattering) that are amenable to studies of biomolecules. The absence of lanthanide ions in living systems means that background signals are generally a nonissue; however, to exploit the advantageous properties it is necessary to engineer a robust lanthanide-binding sequence that can be appended to any macromolecules of interest. To this end, the luminescence produced by tryptophan-sensitized Tb(3+) has been used as a selection marker for peptide sequences that avidly chelate these ions. A combinatorial split-and-pool library that uses two orthogonal linkers-one that is cleaved for selection and one that is cleaved for sequencing and characterization-has been used to develop lanthanide-binding tags (LBTs): peptides of 15-20 amino acids with low-nM affinity for Tb(3+). Further validating the success of this screen, knowledge about LBTs has enabled the introduction of a lanthanide-binding loop in place of one of the four native calcium-binding loops within the protein calcineurin B.

  6. 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

  7. 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

  8. Separation of lanthanides through hydroxyapatite

    International Nuclear Information System (INIS)

    Garcia M, F.G.

    2006-01-01

    With the objective of obtaining from an independent way to each one of the lanthanides 151 Pm, 161 Tb, 166 Ho and 177 Lu free of carrier and with high specific activities starting from the indirect irradiation via, it intends in this work to determine the viability of separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu, by means of ion exchange column chromatography, using hydroxyapatite (HAp) and fluorite like absorbent material in complexing media. It is important to mention that have registered separation studies among lanthanides of the heavy group with those of the slight group, using the same mass and, in comparison with this work, quantities different from the father were used and of the son, also, that the separation studies were carried out among neighboring lanthanides. In this investigation, it was determined the effect that its have the complexing media: KSCN, sodium tartrate, sodium citrate, EDTA and aluminon, their pH and concentration, in the adsorption of the lanthanides in both minerals, in order to determine the chromatographic conditions for separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu. The work consists of five chapters, in the first one they are presented a theoretical introduction of the characteristics more important of the lanthanides, the hydroxyapatite and the fluorite; in the second, it is deepened in the ion exchange, as well as the two techniques (XRD and High Vacuum Electron Microscopy) to make the characterization of LnCI 3 (Ln = Nd, Gd, Dy or Yb) synthesized. The third chapter, it describes the methodology continued in our experimental work; in the room, its are presented the obtained results of the static and dynamic method to determine the viability of separation of neighboring lanthanides; and finally, the five chapter shows the conclusions. In this study, it is concludes that the separation among neighboring lanthanides cannot be carried out in the minerals and used media; because practically these lanthanides

  9. 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.

  10. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yin; Huang, Feng [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China); Huber, Thomas [Australian National University, Research School of Chemistry (Australia); Su, Xun-Cheng, E-mail: xunchengsu@nankai.edu.cn [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China)

    2016-02-15

    Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i − 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.

  11. Model for paramagnetic Fermi systems

    International Nuclear Information System (INIS)

    Ainsworth, T.L.; Bedell, K.S.; Brown, G.E.; Quader, K.F.

    1983-01-01

    We develop a mode for paramagnetic Fermi liquids. This model has both direct and induced interactions, the latter including both density-density and current-current response. The direct interactions are chosen to reproduce the Fermi liquid parameters F/sup s/ 0 , F/sup a/ 0 , F/sup s/ 1 and to satify the forward scattering sum rule. The F/sup a/ 1 and F/sup s/,a/sub l/ for l>1 are determined self-consistently by the induced interactions; they are checked aginst experimental determinations. The model is applied in detail to liquid 3 He, using data from spin-echo experiments, sound attenuation, and the velocities of first and zero sound. Consistency with experiments gives definite preferences for values of m. The model is also applied to paramagnetic metals. Arguments are given that this model should provide a basis for calculating effects of magnetic fields

  12. Dating by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Poupeau, G.; Rossi, A.M.

    1984-01-01

    Some natural materials behave like dosimeters in front of the ionizing particle flux coming from environmental radioactivity and the cosmic radiation. This property is used for the dating by Electron Paramagnetic Resonance (EPR). Before presenting the basic principles of the EPR analysis and the dating method which uses such a phenomenous, it is reviewed several types of application currently in course of development. (L.C.) [pt

  13. 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.

  14. Unexpected magnetism, and transport properties in mixed lanthanide compound

    Science.gov (United States)

    Pathak, Arjun; Gschneidner, Karl, Jr.; Pecharsky, Vitalij; Ames Laboratory Team

    For intelligent materials design it is desirable to have compounds which have multiple functionalities such as a large magnetoresistance, ferromagnetic and ferrimagnetic states, and field-induced first-order metamagnetic transitions. Here, we discuss one such example where we have combined two lanthanide elements Pr and Er in Pr0.6Er0.4Al2. This compound exhibits multiple functionalities in magnetic fields between 1 and 40 kOe. It undergoes only a trivial ferrimagnetism to paramagnetism transition in a zero magnetic field, but Pr0.6Er0.4Al2 exhibits a large positive magnetoresistance (MR) for H >=40 kOe, a small but non negligible negative MR for H field cooling from the paramagnetic state. These phenomena are attributed to the competition between single-ion anisotropies of Pr and Er ions coupled with the opposite nearest-neighbor and next-nearest-neighbor exchange interactions. This work was supported by the US Department of Energy, Office of Basic Energy Science, Division of Material Sciences and Engineering. The research was performed at the Ames Laboratory. The Ames Laboratory is operated by Iowa State University for the US D.

  15. Paramagnetic decoration of DNA origami nanostructures by Eu³⁺ coordination.

    Science.gov (United States)

    Opherden, Lars; Oertel, Jana; Barkleit, Astrid; Fahmy, Karim; Keller, Adrian

    2014-07-15

    The folding of DNA into arbitrary two- and three-dimensional shapes, called DNA origami, represents a powerful tool for the synthesis of functional nanostructures. Here, we present the first approach toward the paramagnetic functionalization of DNA origami nanostructures by utilizing postassembly coordination with Eu(3+) ions. In contrast to the usual formation of toroidal dsDNA condensates in the presence of trivalent cations, planar as well as rod-like DNA origami maintain their shape and monomeric state even under high loading with the trivalent lanthanide. Europium coordination was demonstrated by the change in Eu(3+) luminescence upon binding to the two DNA origami. Their natural circular dichroism in the Mg(2+)- and Eu(3+)-bound state was found to be very similar to that of genomic DNA, evidencing little influence of the DNA origami superstructure on the local chirality of the stacked base pairs. In contrast, the magnetic circular dichroism of the Mg(2+)-bound DNA origami deviates from that of genomic DNA. Furthermore, the lanthanide affects the magnetic properties of DNA in a superstructure-dependent fashion, indicative of the existence of superstructure-specific geometry of Eu(3+) binding sites in the DNA origami that are not formed in genomic DNA. This simple approach lays the foundation for the generation of magneto-responsive DNA origami nanostructures. Such systems do not require covalent modifications and can be used for the magnetic manipulation of DNA nanostructures or for the paramagnetic alignment of molecules in NMR spectroscopy.

  16. Cys-Ph-TAHA: a lanthanide binding tag for RDC and PCS enhanced protein NMR

    International Nuclear Information System (INIS)

    Peters, Fabian; Maestre-Martinez, Mitcheell; Leonov, Andrei; Kovačič, Lidija; Becker, Stefan; Boelens, Rolf; Griesinger, Christian

    2011-01-01

    Here we present Cys-Ph-TAHA, a new nonadentate lanthanide tag for the paramagnetic labelling of proteins. The tag can be easily synthesized and is stereochemically homogenous over a wide range of temperatures, yielding NMR spectra with a single set of peaks. Bound to ubiquitin, it induced large residual dipolar couplings and pseudocontact shifts that could be measured easily and agreed very well with the protein structure. We show that Cys-Ph-TAHA can be used to label large proteins that are biochemically challenging such as the Lac repressor in a 90 kDa ternary complex with DNA and inducer.

  17. 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.

  18. 2. Intermetallic compounds with lanthanides

    International Nuclear Information System (INIS)

    Elemans, J.B.A.A.

    1975-01-01

    Theoretical considerations are given concerning the structures of intermetallic compounds of the lanthanides and thorium (R) on the one hand, and with Fe, Co or Ni (M) on the other. They all derive from the parent composition RM 5 with the CaCu 5 hexagonal structure. This consists of alternate layers in which the M atoms are distinguished as M 1 and M 2 . The other compounds whose structures are studied are obtained by systematic replacement of R by M, or vice versa. In the first type, every third R is replaced by two M's yielding R 2 M 17 compounds. The substitution may be truly random or structured in two ways: so that either the hexagonal structure is maintained or that it is converted into a rhombihedral one. In the second type, one M (in a M 1 position) out of every five is replaced by one R, giving rise to RM 2 compounds which form Laves phases. In the third type, the M 1 's are replaced by R's, resulting in compounds RM 3 . In the fourth type, every third M is replaced by R, yielding R 2 M 7 compounds. With M = Co and R a light lanthanide, the compounds are ferromagnets; with R yttrium, thorium, or a heavy lanthanide, they are ferrimagnets. The preparation of the compounds in an arc-melting apparatus under an Ar-atmosphere followed by annealing is described

  19. Characterizing the magnetic susceptibility tensor of lanthanide-containing polymethylated-DOTA complexes

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, Madeleine [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States); Schwieters, Charles D. [National Institutes of Health, Office of Intramural Research, Center for Information Technology (United States); Göbl, Christoph [Technische Universität München, Department of Chemistry (Germany); Opina, Ana C. L. [National Institutes of Health, Imaging Probe Development Center, National Heart, Lung, and Blood Institute (United States); Strub, Marie-Paule [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States); Swenson, Rolf E.; Vasalatiy, Olga [National Institutes of Health, Imaging Probe Development Center, National Heart, Lung, and Blood Institute (United States); Tjandra, Nico, E-mail: tjandran@nhlbi.nih.gov [National Institutes of Health, Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute (United States)

    2016-10-15

    Lanthanide complexes based on the DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) cage are commonly used as phase contrast agents in magnetic resonance imaging, but can also be utilized in structural NMR applications due to their ability to induce either paramagnetic relaxation enhancement or a pseudocontact shift (PCS) depending on the choice of the lanthanide. The size and sign of the PCS for any given atom is determined by its coordinates relative to the metal center, and the characteristics of the lanthanide’s magnetic susceptibility tensor. Using a polymethylated DOTA tag (Ln-M8-SPy) conjugated to ubiquitin, we calculated the position of the metal center and characterized the susceptibility tensor for a number of lanthanides (dysprosium, thulium, and ytterbium) under a range of pH and temperature conditions. We found that there was a difference in temperature sensitivity for each of the complexes studied, which depended on the size of the lanthanide ion as well as the isomeric state of the cage. Using {sup 17}O-NMR, we confirmed that the temperature sensitivity of the compounds was enhanced by the presence of an apically bound water molecule. Since amide-containing lanthanide complexes are known to be pH sensitive and can be used as probes of physiological pH, we also investigated the effect of pH on the Ln-M8-SPy susceptibility tensor, but we found that the changes in this pH range (5.0–7.4) were not significant.

  20. Characterizing the magnetic susceptibility tensor of lanthanide-containing polymethylated-DOTA complexes

    International Nuclear Information System (INIS)

    Strickland, Madeleine; Schwieters, Charles D.; Göbl, Christoph; Opina, Ana C. L.; Strub, Marie-Paule; Swenson, Rolf E.; Vasalatiy, Olga; Tjandra, Nico

    2016-01-01

    Lanthanide complexes based on the DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) cage are commonly used as phase contrast agents in magnetic resonance imaging, but can also be utilized in structural NMR applications due to their ability to induce either paramagnetic relaxation enhancement or a pseudocontact shift (PCS) depending on the choice of the lanthanide. The size and sign of the PCS for any given atom is determined by its coordinates relative to the metal center, and the characteristics of the lanthanide’s magnetic susceptibility tensor. Using a polymethylated DOTA tag (Ln-M8-SPy) conjugated to ubiquitin, we calculated the position of the metal center and characterized the susceptibility tensor for a number of lanthanides (dysprosium, thulium, and ytterbium) under a range of pH and temperature conditions. We found that there was a difference in temperature sensitivity for each of the complexes studied, which depended on the size of the lanthanide ion as well as the isomeric state of the cage. Using "1"7O-NMR, we confirmed that the temperature sensitivity of the compounds was enhanced by the presence of an apically bound water molecule. Since amide-containing lanthanide complexes are known to be pH sensitive and can be used as probes of physiological pH, we also investigated the effect of pH on the Ln-M8-SPy susceptibility tensor, but we found that the changes in this pH range (5.0–7.4) were not significant.

  1. Electron paramagnetic resonance (EPR) biodosimetry

    International Nuclear Information System (INIS)

    Desrosiers, Marc; Schauer, David A.

    2001-01-01

    Radiation-induced electron paramagnetic resonance (EPR) signals were first reported by Gordy et al. [Proc. Natl. Acad. Sci. USA 41 (1955) 983]. The application of EPR spectroscopy to ionizing radiation dosimetry was later proposed by Brady et al. [Health Phys. 15 (1968) 43]. Since that time EPR dosimetry has been applied to accident and epidemiologic dose reconstruction, radiation therapy, food irradiation, quality assurance programs and archaeological dating. Materials that have been studied include bone, tooth enamel, alanine and quartz. This review paper presents the fundamentals and applications of EPR biodosimetry. Detailed information regarding sample collection and preparation, EPR measurements, dose reconstruction, and data analysis and interpretation will be reviewed for tooth enamel. Examples of EPR biodosimetry application in accidental overexposures, radiopharmaceutical dose assessment and retrospective epidemiologic studies will also be presented

  2. Paramagnetic pharmaceuticals for functional studies

    International Nuclear Information System (INIS)

    Hall, L.D.; Hogan, P.G.

    1987-01-01

    It has been suggested that limitations of the Magnetic Resonance Imaging (MRI) method may be minimised by the use of ''image contrast'' agents. These are exogenous chemicals administered to the patient which, by influencing the magnetic resonance properties of the water in the region of the pathology, serve to heighten the contrast between that tissue and its surroundings. At present the most widely used agent is gadolinium-DTPA (Gd-DTPA). This appears to have many desirable features and its development provides a textbook example for the early stages of any future development. All compounds used so far can be subdivided into one of the following categories: Paramagnetic metal species; Ferromagnetic metal species; Stable free radicals; Oxygen carriers; Susceptibility agents; and Density substitution agents. The authors summarise briefly these chemical substances and their reported uses

  3. Lanthanides, thorium, iodine in terrestrail invertebrates

    International Nuclear Information System (INIS)

    Zhulidov, A.V.; Pokarzhevskij, A.D.; Katargin, N.V.; AN SSSR, Moscow

    1991-01-01

    It is shown that among examined terrestrial invertebrates the highest levels on lanthanide and thorium concentration are typical for animals, feeding on plant tissues - earthworms, molluscs, diploid. It is shown that there are no reasons to hope, that regularities of migration of transuranium elements and lanthanides in tropic chains are identical

  4. A sensitive fluorescent sensor of lanthanide ions

    CERN Document Server

    Bekiari, V; Lianos, P

    2003-01-01

    A fluorescent probe bearing a diazostilbene chromophore and a benzo-15-crown-5 ether moiety is a very efficient sensor of lanthanide ions. The ligand emits strong fluorescence only in the presence of specific ions, namely lanthanide ions, while the emission wavelength is associated with a particular ion providing high sensitivity and resolution.

  5. 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.

  6. Lanthanide-doped luminescent ionogels

    OpenAIRE

    Lunstroot, Kyra; Driesen, Kris; Nockemann, Peter; Van Hecke, Kristof; Van Meervelt, Luc; Görller-Walrand, Christiane; Binnemans, Koen; Bellayer, Séverine; Viau, Lydie; Le Bideau, Jean; Vioux, André

    2009-01-01

    Ionogels are solid oxide host networks confining at a meso-scale ionic liquids, and retaining their liquid nature. Ionogels were obtained by dissolving anthanide(III) complexes in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][Tf2N], followed by confinement of the lanthanide-doped ionic liquid mixtures in the pores of a nano-porous silica network. [C6mim][Ln(tta)4], where tta is 2-thenoyltrifluoroacetonate and Ln = Nd, Sm, Eu, Ho, Er, Yb, and [choli...

  7. 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.

  8. Decay of paramagnetic centers in polyacetylene

    International Nuclear Information System (INIS)

    Hola, O.

    1994-01-01

    The time dependences of the relative concentration of spins in irradiated and unirradiated samples of polyacetylene have been studied. Similar courses of the decay of paramagnetic centers were observed in both types of samples. (author) 6 refs.; 1 fig

  9. Symmetric Imidazolium-Based Paramagnetic Ionic Liquids

    Science.gov (United States)

    2017-11-29

    Charts N/A Unclassified Unclassified Unclassified SAR 14 Kamran Ghiassi N/A 1 Symmetric Imidazolium-Based Paramagnetic Ionic Liquids Kevin T. Greeson...NUMBER (Include area code) 29 November 2017 Briefing Charts 01 November 2017 - 30 November 2017 Symmetric Imidazolium-Based Paramagnetic Ionic ... Liquids K. Greeson, K. Ghiassi, J. Alston, N. Redeker, J. Marcischak, L. Gilmore, A. Guenthner Air Force Research Laboratory (AFMC) AFRL/RQRP 9 Antares

  10. 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.

  11. Lanthanide shift reagents, binding, shift mechanisms and exchange

    International Nuclear Information System (INIS)

    Boer, J.W.M. de

    1977-01-01

    Paramagnetic lanthanide shift reagents, when added to a solution of a substrate, induce shifts in the nuclear magnetic resonance (NMR) spectrum of the substrate molecules. The induced shifts contain information about the structure of the shift reagent substrate complex. The structural information, however, may be difficult to extract because of the following effects: (1) different complexes between shift reagent and substrate may be present in solution, e.g. 1:1 and 1:2 complexes, and the shift observed is a weighed average of the shifts of the substrate nuclei in the different complexes; (2) the Fermi contact interaction, arising from the spin density at the nucleus, contributes to the induced shift; (3) chemical exchange effects may complicate the NMR spectrum. In this thesis, the results of an investigation into the influence of these effects on the NMR spectra of solutions containing a substrate and LSR are presented. The equations describing the pseudo contact and the Fermi contact shift are derived. In addition, it is shown how the modified Bloch equations describing the effect of the chemical exchange processes occurring in the systems studied can be reduced to the familiar equations for a two-site exchange case. The binding of mono- and bifunctional ethers to the shift reagent are reported. An analysis of the induced shifts is given. Finally, the results of the experiments performed to study the exchange behavior of dimethoxyethane and heptafluorodimethyloctanedionato ligands are presented

  12. Nonaqueous method for dissolving lanthanide and actinide metals

    International Nuclear Information System (INIS)

    Crisler, L.R.

    1975-01-01

    Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol

  13. Buckling of paramagnetic chains in soft gels

    Science.gov (United States)

    Huang, Shilin; Pessot, Giorgio; Cremer, Peet; Weeber, Rudolf; Holm, Christian; Nowak, Johannes; Odenbach, Stefan; Menzel, Andreas M.; Auernhammer, Günter K.

    We study the magneto-elastic coupling behavior of paramagnetic chains in soft polymer gels exposed to external magnetic fields. To this end, a laser scanning confocal microscope is used to observe the morphology of the paramagnetic chains together with the deformation field of the surrounding gel network. The paramagnetic chains in soft polymer gels show rich morphological shape changes under oblique magnetic fields, in particular a pronounced buckling deformation. The details of the resulting morphological shapes depend on the length of the chain, the strength of the external magnetic field, and the modulus of the gel. Based on the observation that the magnetic chains are strongly coupled to the surrounding polymer network, a simplified model is developed to describe their buckling behavior. A coarse-grained molecular dynamics simulation model featuring an increased matrix stiffness on the surfaces of the particles leads to morphologies in agreement with the experimentally observed buckling effects.

  14. New Lanthanide Alkynylamidinates and Diiminophosphinates

    Directory of Open Access Journals (Sweden)

    Farid M. Sroor

    2015-11-01

    Full Text Available This contribution reports the synthesis and structural characterization of several new lithium and lanthanide alkynylamidinate complexes. Treatment of PhC≡CLi with N,N′-diorganocarbodiimides, R–N=C=N–R (R = iPr, Cy (cyclohexyl, in THF or diethyl ether solution afforded the lithium-propiolamidinates Li[Ph–C≡C–C(NCy2] S (1: R = iPr, S = THF; 2: R = Cy, S = THF; 3: R = Cy, S = Et2O. Single-crystal X-ray diffraction studies of 1 and 2 showed the presence of typical ladder-type dimeric structures in the solid state. Reactions of anhydrous LnCl3 (Ln = Ce, Nd, Sm or Ho with 2 in a 1:3 molar ratio in THF afforded a series of new homoleptic lanthanide tris(propiolamidinate complexes, [Ph–C≡C–C(NCy2]3Ln (4: Ln = Ce; 5: Ln = Nd; 6: Ln = Sm; 7: Ln = Ho. The products were isolated in moderate to high yields (61%–89% as brightly colored, crystalline solids. The chloro-functional neodymium(III bis(cyclopropylethynylamidinate complex [{c-C3H5–C≡C–C(NiPr2}2Ln(µ-Cl(THF]2 (8 was prepared from NdCl3 and two equiv. of Li[c-C3H5–C≡C–C(NiPr2] in THF and structurally characterized. A new monomeric Ce(III-diiminophosphinate complex, [Ph2P(NSiMe32]2Ce(µ-Cl2Li(THF2 (9, has also been synthesized in a similar manner from CeCl3 and two equiv. of Li[Ph2P(NSiMe32]. Structurally, this complex resembles the well-known “ate” complexes (C5Me52Ln(µ-Cl2Li(THF2. Attempts to oxidize compound 9 using trityl chloride or phenyliodine(III dichloride did not lead to an isolable cerium(IV species.

  15. Intermolecular dynamics studied by paramagnetic tagging

    Energy Technology Data Exchange (ETDEWEB)

    Xu Xingfu; Keizers, Peter H. J. [Leiden University, Institute of Chemistry (Netherlands); Reinle, Wolfgang; Hannemann, Frank; Bernhardt, Rita [Universitaet des Saarlandes, Naturwissenschaftlich-Technische Fakultaet III, Institut fuer Biochemie (Germany); Ubbink, Marcellus [Leiden University, Institute of Chemistry (Netherlands)], E-mail: m.ubbink@chem.leidenuniv.nl

    2009-04-15

    Yeast cytochrome c and bovine adrenodoxin form a dynamic electron transfer complex, which is a pure encounter complex. It is demonstrated that the dynamic nature of the interaction can readily be probed by using a rigid lanthanide tag attached to cytochrome c. The tag, Caged Lanthanide NMR Probe 5, induces pseudocontact shifts and residual dipolar couplings and does not perturb the binding interface. Due to the dynamics in the complex, residual dipolar couplings in adrenodoxin are very small. Simulation shows that cytochrome c needs to sample a large part of the surface of adrenodoxin to explain the small degree of alignment observed for adrenodoxin. The applied method provides a simple and straightforward way to observe dynamics in protein complexes or domain-domain mobility without the need for external alignment media.

  16. Intermolecular dynamics studied by paramagnetic tagging

    International Nuclear Information System (INIS)

    Xu Xingfu; Keizers, Peter H. J.; Reinle, Wolfgang; Hannemann, Frank; Bernhardt, Rita; Ubbink, Marcellus

    2009-01-01

    Yeast cytochrome c and bovine adrenodoxin form a dynamic electron transfer complex, which is a pure encounter complex. It is demonstrated that the dynamic nature of the interaction can readily be probed by using a rigid lanthanide tag attached to cytochrome c. The tag, Caged Lanthanide NMR Probe 5, induces pseudocontact shifts and residual dipolar couplings and does not perturb the binding interface. Due to the dynamics in the complex, residual dipolar couplings in adrenodoxin are very small. Simulation shows that cytochrome c needs to sample a large part of the surface of adrenodoxin to explain the small degree of alignment observed for adrenodoxin. The applied method provides a simple and straightforward way to observe dynamics in protein complexes or domain-domain mobility without the need for external alignment media

  17. Paramagnetism: an alternative view. Pt. 1

    International Nuclear Information System (INIS)

    Oudet, X.

    1991-01-01

    A new calculation of the paramagnetic susceptibility χ is proposed on the basis of the statistical distribution of the thermal energy using the mean value U of this energy as statistical variable. This allows us to replace the molecular field by an equivalent energy barrier that the paramagnetic moment of an atom has to cross to contribute to χ. The variation of χ with U, or T as well, shows a maximum when there is no magnetic order. The asymptotic character of the Curie-Weiss law appears in close connection with that of the Dulong and Petit law. (orig.)

  18. Paramagnetic defects in hydrogenated amorphous carbon powders

    International Nuclear Information System (INIS)

    Keeble, D J; Robb, K M; Smith, G M; Mkami, H El; Rodil, S E; Robertson, J

    2003-01-01

    Hydrogenated amorphous carbon materials typically contain high concentrations of paramagnetic defects, the density of which can be quantified by electron paramagnetic resonance (EPR). In this work EPR measurements near 9.5, 94, and 189 GHz have been performed on polymeric and diamond-like hydrogenated amorphous carbon (a-C:H) powder samples. A similar single resonance line was observed at all frequencies for the two forms of a-C:H studied. No contributions to the spectrum from centres with resolved anisotropic g-values as reported earlier were detected. An increase in linewidth with microwave frequency was observed. Possible contributions to this frequency dependence are discussed

  19. 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)

  20. Lanthanides in the frame of Molecular Magnetism

    Directory of Open Access Journals (Sweden)

    Gatteschi D.

    2014-07-01

    Full Text Available Molecular magnetism is producing new types of materials which cover up to date aspects of basic science together with possible applications. This article highlights recent results from the point of view of lanthanides which are now intensively used to produce single molecule magnets, single chain and single ion magnets. After a short introduction reminding the main steps of development of molecular magnetism, the basic properties of lanthanides will be covered highlighting important features which are enhanced by the electronic structure of lanthanides, like spin frustration and chirality, anisotropy and non collinear axes in zero and one dimensional materials. A paragraph of conclusions will discuss what has been done and theperspectives to be expected.

  1. Curvature of the Lanthanide Contraction: An Explanation

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, Kenneth; Wellman, Daniel; Sgarlata, Carmelo; Hill, Aru

    2009-12-21

    A number of studies have shown that for isostructural series of the lanthanides (elements La through Lu), a plot of equivalent metal-ligand bond lengths versus atomic number differs significantly from linearity and can be better fit as a quadratic equation. However, for hydrogen type wave functions, it is the inverse of the average distance of the electron from the nucleus (an estimate of size) that varies linearly with effective nuclear charge. This generates an apparent quadratic dependence of radius with atomic number. Plotting the inverse of lanthanide ion radii (the observed distance minus the ligand size) as a function of effective nuclear charge gives very good linear fits for a variety of lanthanide complexes and materials. Parameters obtained from this fit are in excellent agreement with the calculated Slater shielding constant, k.

  2. Theoretical study of the electron paramagnetic resonance ...

    Indian Academy of Sciences (India)

    conveniently investigated by means of electron paramagnetic resonance (EPR). In ... ion Ir2+ can experience the Jahn–Teller effect by means of vibration interaction, ... Similarly, k. (and k ) are the orbital reduction factors arising from the anisotropic interactions of the orbital angular momentum operator. From the cluster ...

  3. Recent results on some columnar paramagnetic metallomesogens

    Indian Academy of Sciences (India)

    A broader view on some physical properties of columnar paramagnetic ... was evident by X-ray crystal structure determination in the solid state on a homologous ... leading to interfacial polarization as described for other LC materials before [9]. ... dodecyloxy tail on the phenyl rings) was described to exhibit a Colho phase ...

  4. Microassembly using a Cluster of Paramagnetic Microparticles

    NARCIS (Netherlands)

    Khalil, I.S.M.; Brink, F.V; Sardan Sukas, Ö.; Misra, Sarthak

    2013-01-01

    We use a cluster of paramagnetic microparticles to carry out a wireless two-dimensional microassembly operation. A magnetic-based manipulation system is used to control the motion of the cluster under the influence of the applied magnetic fields. Wireless motion control of the cluster is implemented

  5. Depolarization of diffusing spins by paramagnetic impurities

    International Nuclear Information System (INIS)

    Schillaci, M.E.; Hutson, R.L.; Heffner, R.H.; Leon, M.; Dodds, S.A.; Estle, T.L.

    1981-01-01

    We study the depolarization of diffusing spins (muons) interacting with dilute paramagnetic impurities in a solid using a simple computational model which properly treats the muon motion and preserves correct muon-impurity distances. Long-range (dipolar) and nearest-neighbor (contact) interactions are treated together. Diffusion parameters are deduced and model comparisons made for AuGd (300 ppm). (orig.)

  6. Dual excitation acoustic paramagnetic logging tool

    Energy Technology Data Exchange (ETDEWEB)

    Vail, III, William B. (Bothell, WA)

    1989-01-01

    New methods and apparatus are disclosed which allow measurement of the presence of oil and water in gelogical formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleous present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described.

  7. A superheterodyne spectrometer for electronic paramagnetic. Resonance

    International Nuclear Information System (INIS)

    Laffon, J.L.

    1963-12-01

    After a few generalities about electron paramagnetic resonance, a consideration of different experimental techniques authorises the choice of a particular type of apparatus. An EPR superheterodyne spectrometer built in the laboratory and having a novel circuit is described in detail. With this apparatus, many experimental results have been obtained and some of these are described as example. (author) [fr

  8. 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)

  9. Catalytic activation of molecular hydrogen in alkyne hydrogenation reactions by lanthanide metal vapor reaction products

    International Nuclear Information System (INIS)

    Evans, W.J.; Bloom, I.; Engerer, S.C.

    1983-01-01

    A rotary metal vapor was used in the synthesis of Lu, Er, Nd, Sm, Yb, and La alkyne, diene, and phosphine complexes. A typical catalytic hydrogenation experiment is described. The lanthanide metal vapor product is dissolved in tetrahydrofuran or toluene and placed in a pressure reaction vessel 3-hexyne (or another substrate) is added, the chamber attached to a high vacuum line, cooled to -196 0 C, evacuated, warmed to ambient temperature and hydrogen is added. The solution is stirred magnetically while the pressure in monitored. The reaction products were analyzed by gas chromatography. Rates and products of various systems are listed. This preliminary survey indicates that catalytic reaction chemistry is available to these metals in a wide range of coordination environments. Attempts to characterize these compounds are hampered by their paramagnetic nature and their tendency to polymerize

  10. The electronic structure of adducts derived from tris(cyclopentadienyl)-lanthanide(III)

    International Nuclear Information System (INIS)

    Amberger, H.D.; Edelstein, N.M.

    1985-01-01

    On the basis of magneto-optical and optical data of adducts derived from tris (eta/sup 5/-cyclopentadienyl)-lanthanide(III) (Ln = Pr, Nd, Er) the underlying crystal field (CF) splitting patterns could be derived. Fitting the parameters of an empirical Hamiltonian to these CF splitting patterns, the CF eigenvalues and CF eigenfunctions were obtained. By means of these data the experimental temperature dependence of the paramagnetic susceptibility could be reproduced by choosing orbital reduction factors between 0.950 and 0.975, respectively. The contact contribution of the /sup 1/H-NMR shifts of the cyclopentadienide protons of Cp/sub 3/Pr . CNC/sub 6/H/sub 11/ could be simulated by adopting a hyperfine coupling parameter A/sub F/ = vertical bar 0.236 vertical bar MHz

  11. Oligomerization of Paramagnetic Substrates Result in Signal Amplification and Can be Used for MR Imaging of Molecular Targets

    Directory of Open Access Journals (Sweden)

    Alexei Bogdanov

    2002-01-01

    Full Text Available Magnetic resonance imaging (MRI has evolved into a sophisticated, noninvasive imaging modality capable of high-resolution anatomical and functional characterization of transgenic animals. To expand the capabilities MRI, we have developed a novel MR signal amplification (MRamp strategy based on enzyme-mediated polymerization of paramagnetic substrates into oligomers of higher magnetic relaxivity. The substrates consist of chelated gadolinium covalently bound to phenols, which then serve as electron donors during enzymatic hydrogen peroxide reduction by peroxidase. The converted monomers undergo rapid condensation into paramagnetic oligomers leading to a threefold increase in atomic relaxivity (R1/Gd. The observed relaxivity changes are largely due to an increase in the rotational correlation time τr of the lanthanide. Three applications of the developed system are demonstrated: (1 imaging of nanomolar amounts of an oxidoreductase (peroxidase; (2 detection of a model ligand using an enzyme-linked immunoadsorbent assay format; and (3 imaging of E-selectin on the surface of endothelial cells probed for with an anti-E-selectin – peroxidase conjugate. The development of “enzyme sensing” probes is expected to have utility for a number of applications including in vivo detection of specific molecular targets. One particular advantage of the MRamp technique is that the same paramagnetic substrate can be potentially used to identify different molecular targets by attaching enzymes to various antibodies or other target-seeking molecules.

  12. Gamma ray induced decomposition of lanthanide nitrates

    International Nuclear Information System (INIS)

    Joshi, N.G.; Garg, A.N.

    1992-01-01

    Gamma ray induced decomposition of the lanthanide nitrates, Ln(NO 3 ) 3 .xH 2 O where Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm and Yb has been studied at different absorbed doses up to 600 kGy. G(NO 2 - ) values depend on the absorbed dose and the nature of the outer cation. It has been observed that those lanthanides which exhibit variable valency (Ce and Eu) show lower G-values. An attempt has been made to correlate thermal and radiolytic decomposition processes. (author). 20 refs., 3 figs., 1 tab

  13. Factors in the complexation of lanthanides

    International Nuclear Information System (INIS)

    Choppin, G.R.

    1976-01-01

    The lanthanide cations are classified as hard acids and thus will coordinate strongly with oxygen and fluorine donor atoms. The electrostatic model is applied to lanthanide complexes with the dielectric constant as a parameter; the plot of ΔG vs sum of ionic radii confirm the ionic nature of the bonding. The enthalpy and entropy changes are shown to compensate each other to produce an almost linear variation in the free energy of complexation. Outer-sphere and inner-sphere complexation is discussed

  14. 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)

  15. The application of electron paramagnetic resonance in biomedical research

    International Nuclear Information System (INIS)

    Qu Ximei; Wang Liqin; Zhang Wenyi; Liu Zhongchao; Cui Songye; Feng Xin; Jiaoling

    2013-01-01

    Electron paramagnetic resonance technique has been found more than half a century, for free radicals detection application, it has been applied to various research studies, and promotes the development of the biomedicine. This article summarized the various free radicals measurement by the electron paramagnetic resonance in biology tissue, and the application of the spin labeling and electron paramagnetic resonance imaging technology in biomedicine. (authors)

  16. Structural biology of the lanthanides-mining rare earths in the Protein Data Bank.

    Science.gov (United States)

    Djinovic-Carugo, Kristina; Carugo, Oliviero

    2015-02-01

    With its about 100,000 three-dimensional structures, the Protein Data Bank is a copious source of information: it contains also some hundreds of structures of macromolecules complexed with lanthanide cations, which are examined here. These cations, which are found in a wide variety of protein types, were introduced to determine the structures, by exploiting their anomalous dispersion (in crystallographic studies, where they are also used as crystallization additives) or the paramagnetic pseudocontact shifts (in NMR analyses). The coordination numbers in the first coordination sphere are very variable, though they tend to be close to those that are observed in small molecules or in water solution. The coordination polyhedra are also quite variable as it can be expected for large cations. Interestingly, lanthanide cations are frequently observed in packing bridges between symmetry equivalent molecules in crystals, where they tend to form polynuclear complexes, with up to seven cations bridged by water/hydroxide ligands. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Engineering [Ln(DPA){sub 3}]{sup 3-} binding sites in proteins: a widely applicable method for tagging proteins with lanthanide ions

    Energy Technology Data Exchange (ETDEWEB)

    Jia Xinying; Yagi, Hiromasa; Su Xuncheng; Stanton-Cook, Mitchell; Huber, Thomas; Otting, Gottfried, E-mail: gottfried.otting@anu.edu.au [Australian National University, Research School of Chemistry (Australia)

    2011-08-15

    Paramagnetic relaxation enhancements from unpaired electrons observed in nuclear magnetic resonance (NMR) spectra present powerful long-range distance restraints. The most frequently used paramagnetic tags, however, are tethered to the protein via disulfide bonds, requiring proteins with single cysteine residues for covalent attachment. Here we present a straightforward strategy to tag proteins site-specifically with paramagnetic lanthanides without a tether and independent of cysteine residues. It relies on preferential binding of the complex between three dipicolinic acid molecules (DPA) and a lanthanide ion (Ln{sup 3+}), [Ln(DPA){sub 3}]{sup 3-}, to a pair of positively charged amino acids whose charges are not compensated by negatively charged residues nearby. This situation rarely occurs in wild-type proteins, allowing the creation of specific binding sites simply by introduction of positively charged residues that are positioned far from glutamate or aspartate residues. The concept is demonstrated with the hnRNPLL RRM1 domain. In addition, we show that histidine- and arginine-tags present binding sites for [Ln(DPA){sub 3}]{sup 3-}.

  18. Studies of Lanthanide Transport in Metallic Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinsuo; Taylor, Christopher

    2018-04-02

    Metallic nuclear fuels were tested in fast reactor programs and performed well. However, metallic fuels have shown the phenomenon of FCCI that are due to deleterious reactions between lanthanide fission products and cladding material. As the burnup is increased, lanthanide fission products that contact with the cladding could react with cladding constituents such as iron and chrome. These reactions produce higher-melting intermetallic compounds and low-melting alloys, and weaken the mechanical integrity. The lanthanide interaction with clad in metallic fuels is recognized as a long-term, high-burnup cause of the clad failures. Therefore, one of the key concerns of using metallic fuels is the redistribution of lanthanide fission products and migration to the fuel surface. It is believed that lanthanide migration is in part due to the thermal gradient between the center and the fuel-cladding interface, but also largely in part due to the low solubility of lanthanides within the uranium-based metal fuel. PIE of EBR-II fuels shows that lanthanides precipitate directly and do not dissolve to an appreciable extent in the fuel matrix. Based on the PIE data from EBR-II, a recent study recommended a so-called “liquid-like” transport mechanism for lanthanides and certain other species. The liquid-like transport model readily accounts for redistribution of Ln, noble metal fission products, and cladding components in the fuel matrix. According to the novel mechanism, fission products can transport as solutes in liquid metals, such as liquid cesium or liquid cesium–sodium, and on pore surfaces and fracture surfaces for metals near their melting temperatures. Transport in such solutions is expected to be much more rapid than solid-state diffusion. The mechanism could explain the Ln migration to the fuel slug peripheral surface and their deposition with a sludge-like form. Lanthanides have high solubility in liquid cesium but have low solubility in liquid sodium. As a

  19. On the paramagnetism of spin in the classical limit

    International Nuclear Information System (INIS)

    Hogreve, H.

    1985-12-01

    We consider particles with spin 1/2 in external electromagnetic fields. Although in many quantum mechanical situations they show a paramagnetic behaviour, within non-relativistic quantum theory a universal paramagnetic influence of spin fails to be true in general. Here we investigate the paramagnetism of spin in the framework of a classical theory. Applying previous results for the classical limit slash-h→O we obtain a classical expression corresponding to the quantum partition function of Hamiltonians with spin variables. For this classical partition function simple estimates lead to a paramagnetic inequality which demonstrates that indeed in the classical limit the spin shows a general paramagnetic behaviour. (author)

  20. Study of actinide paramagnetism in solution

    International Nuclear Information System (INIS)

    Autillo, Matthieu

    2015-01-01

    The physiochemical properties of actinide (An) solutions are still difficult to explain, particularly the behavioral differences between An(III) and Ln(III). The study of actinide paramagnetic behavior may be a 'simple' method to analyze the electronic properties of actinide elements and to obtain information on the ligand-actinide interaction. The objective of this PhD thesis is to understand the paramagnetic properties of these elements by magnetic susceptibility measurements and chemical shift studies. Studies on actinide electronic properties at various oxidation states in solution were carried out by magnetic susceptibility measurements in solution according to the Evans method. Unlike Ln(III) elements, there is no specific theory describing the magnetic properties of these ions in solution. To obtain accurate data, the influence of experimental measurement technique and radioactivity of these elements was analyzed. Then, to describe the electronic structure of their low energy states, the experimental results were complemented with quantum chemical calculations from which the influence of the ligand field was studied. Finally, these interpretations were applied to better understand the variations in the magnetic properties of actinide cations in chloride and nitrate media. Information about ligand-actinide interactions may be determined from an NMR chemical shift study of actinide complexes. Indeed, modifications induced by a paramagnetic complex can be separated into two components. The first component, a Fermi contact contribution (δ_c) is related to the degree of covalency in coordination bonds with the actinide ions and the second, a dipolar contribution (δ_p_c) is related to the structure of the complex. The paramagnetic induced shift can be used only if we can isolate these two terms. To achieve this study on actinide elements, we chose to work with the complexes of dipicolinic acid (DPA). Firstly, to characterize the geometrical parameters, a

  1. Paramagnetic form factors from itinerant electron theory

    International Nuclear Information System (INIS)

    Cooke, J.F.; Liu, S.H.; Liu, A.J.

    1985-01-01

    Elastic neutron scattering experiments performed over the past two decades have provided accurate information about the magnetic form factors of paramagnetic transition metals. These measurements have traditionally been analyzed in terms of an atomic-like theory. There are, however, some cases where this procedure does not work, and there remains the overall conceptual problem of using an atomistic theory for systems where the unpaired-spin electrons are itinerant. We have recently developed computer codes for efficiently evaluating the induced magnetic form factors of fcc and bcc itinerant electron paramagnets. Results for the orbital and spin contributions have been obtained for Cr, Nb, V, Mo, Pd, and Rh based on local density bands. By using calculated spin enhancement parameters, we find reasonable agreement between theory and neutron form factor data. In addition, these zero parameter calculations yield predictions for the bulk susceptibility on an absolute scale which are in reasonable agreement with experiment in all treated cases except palladium

  2. Role of spinning electrons in paramagnetic phenomena

    International Nuclear Information System (INIS)

    Bose, D.M.

    1986-06-01

    An attempt is made to explain paramagnetic phenomena without assuming the orientation of a molecule or ion in a magnetic field. Only the spin angular momentum is assumed to be responsible. A derivative of the Gurie-Langevin law and the magnetic moments of ions are given as a function of the number of electrons in an inner, incomplete shell. An explanation of Gerlach's experiments with iron and nickel vapors is attempted. An explanation of magnetomechanical experiments with ferromagnetic elements is given

  3. Multifrequency Electron Paramagnetic Resonance Theory and Applications

    CERN Document Server

    Misra, Sushil K

    2011-01-01

    Filling the gap for a systematic, authoritative, and up-to-date review of this cutting-edge technique, this book covers both low and high frequency EPR, emphasizing the importance of adopting the multifrequency approach to study paramagnetic systems in full detail by using the EPR method. In so doing, it discusses not only the underlying theory and applications, but also all recent advances -- with a final section devoted to future perspectives.

  4. 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)

  5. EPR in characterization of seeds paramagnetic species

    International Nuclear Information System (INIS)

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C.

    2011-01-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe 2 O 3 ), magnetite (Fe 3 O 4 ), and ferrihydrite (Fe 5 HO 8 · 4H 2 O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn 2+ , which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band (∼ 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe 3+ present in the goethite at g ∼ 2, and in the seeds exist free radicals at g = 2:004, at room temperature

  6. EPR in characterization of seeds paramagnetic species

    Energy Technology Data Exchange (ETDEWEB)

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C. [Universidade Estadual de Londrina (UEL), PR (Brazil)

    2011-07-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), and ferrihydrite (Fe{sub 5}HO{sub 8} {center_dot} 4H{sub 2}O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn{sup 2+}, which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band ({approx} 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe{sup 3+} present in the goethite at g {approx} 2, and in the seeds

  7. Systemic analysis of thermodynamic properties of lanthanide halides

    International Nuclear Information System (INIS)

    Mirsaidov, U.; Badalov, A.; Marufi, V.K.

    1992-01-01

    System analysis of thermodynamic characteristics of lanthanide halides was carried out. A method making allowances for the influence of spin and orbital moments of momentum of the main states of lanthanide trivalent ions in their natural series was employed. Unknown in literature thermodynamic values were calculated and corrected for certain compounds. The character of lanthanide halide thermodynamic parameter change depending on ordinal number of the metals was ascertained. Pronouncement of tetrad-effect in series of compounds considered was pointed out

  8. Lanthanide doped strontium-barium cesium halide scintillators

    Science.gov (United States)

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  9. Ultrasmall lanthanide oxide nanoparticles for biomedical imaging and therapy

    CERN Document Server

    Lee, Gang Ho

    2014-01-01

    Most books discuss general and broad topics regarding molecular imagings. However, Ultrasmall Lanthanide Oxide Nanoparticles for Biomedical Imaging and Therapy, will mainly focus on lanthanide oxide nanoparticles for molecular imaging and therapeutics. Multi-modal imaging capabilities will discussed, along with up-converting FI by using lanthanide oxide nanoparticles. The synthesis will cover polyol synthesis of lanthanide oxide nanoparticles, Surface coatings with biocompatible and hydrophilic ligands will be discussed and TEM images and dynamic light scattering (DLS) patterns will be

  10. 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

  11. 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)

  12. Diagnostic study about lanthanides (rare earths)

    International Nuclear Information System (INIS)

    Ribeiro, G.F.

    1985-01-01

    The world situation of rare earths (lanthanides) is evaluated, and a comparison of the Brazilian situation in respect to other countries is established, concerning the following aspects: geology of mineral deposits; main sources, uses, reserves and production; their consumption, prices and state-of-art of geological researches and industrial processes for physical and chemical separation / concentration of these elements. (C.L.B.) [pt

  13. Electron paramagnetic resonance of transition ions

    CERN Document Server

    Abragam, Anatole

    1970-01-01

    This book is a reissue of a classic Oxford text, and provides a comprehensive treatment of electron paramagnetic resonance of ions of the transition groups. The emphasis is on basic principles, with numerous references to publications containing further experimental results and more detailed developments of the theory. An introductory survey gives a general understanding, and a general survey presents such topics as the classical and quantum resonance equations, thespin-Hamiltonian, Endor, spin-spin and spin-lattice interactions, together with an outline of the known behaviour of ions of each

  14. Electron paramagnetic resonance (EPR) in medical dosimetry

    International Nuclear Information System (INIS)

    Schauer, David A.; Iwasaki, Akinori; Romanyukha, Alexander A.; Swartz, Harold M.; Onori, Sandro

    2006-01-01

    This paper describes the fundamentals of electron paramagnetic resonance (EPR) and its application to retrospective measurements of clinically significant doses of ionizing radiation. X-band is the most widely used in EPR dosimetry because it represents a good compromise between sensitivity, sample size and water content in the sample. Higher frequency bands (e.g., W and Q) provide higher sensitivity, but they are also greatly influenced by water content. L and S bands can be used for EPR measurements in samples with high water content but they are less sensitive than X-band. Quality control for therapeutic radiation facilities using X-band EPR spectrometry of alanine is also presented

  15. Effective core potential methods for the lanthanides

    International Nuclear Information System (INIS)

    Cundari, T.R.; Stevens, W.J.

    1993-01-01

    In this paper a complete set of effective core potentials (ECPs) and valence basis sets for the lanthanides (Ce to Lu) are derived. These ECPs are consistent not only within the lanthanide series, but also with the third-row transition metals which bracket them. A 46-electron core was chosen to provide the best compromise between computational savings and chemical accuracy. Thus, the 5s and 5p are included as ''outer'' core while all lower energy atomic orbitals (AOs) are replaced with the ECP. Generator states were chosen from the most chemically relevant +3 and +2 oxidation states. The results of atomic calculations indicate that the greatest error vs highly accurate numerical potential/large, even-tempered basis set calculations results from replacement of the large, even-tempered basis sets with more compact representations. However, the agreement among atomic calculations remains excellent with both basis set sizes, for a variety of spin and oxidation states, with a significant savings in time for the optimized valence basis set. It is expected that the compact representation of the ECPs and valence basis sets will eventually encourage their use by computational chemists to further explore the bonding and reactivity of lanthanide complexes

  16. About kinetics of paramagnetic radiation malformations in beryllium ceramics

    International Nuclear Information System (INIS)

    Polyakov, A.I.; Ryabinkin, Yu.A.; Zashkvara, O.V.; Bitenbaev, M.I.; Petukhov, Yu.V.

    1999-01-01

    This paper [1] specifies that γ-radiation of the beryllium-oxide-based ceramics results in development of paramagnetic radiation malformations emerging the ESR spectrum in form of doublet with the splitting rate of oestrasid Δ∼1.6 and g-factor of 2.008. This report presents evaluation outcomes of dependence of paramagnetic radiation malformations concentration in beryllium ceramics on gamma-radiation dose ( 60 Co) within the range of 0-100 Mrad. Total paramagnetic parameters of beryllium ceramics in the range 0-100 Mrad of gamma-radiation dose varied slightly, and were specified by the first type of paramagnetic radiation malformations

  17. Lanthanide ions as spectral converters for solar cells

    NARCIS (Netherlands)

    van der Ende, B.M.; Aarts, L.; Meijerink, A.

    2009-01-01

    The use of lanthanide ions to convert photons to different, more useful, wavelengths is well-known from a wide range of applications (e.g. fluorescent tubes, lasers, white light LEDs). Recently, a new potential application has emerged: the use of lanthanide ions for spectral conversion in solar

  18. 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)

  19. 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

  20. Advantages of paramagnetic chemical exchange saturation transfer (CEST) complexes having slow to intermediate water exchange properties as responsive MRI agents.

    Science.gov (United States)

    Soesbe, Todd C; Wu, Yunkou; Dean Sherry, A

    2013-07-01

    Paramagnetic chemical exchange saturation transfer (PARACEST) complexes are exogenous contrast agents that have great potential to further extend the functional and molecular imaging capabilities of magnetic resonance. As a result of the presence of a central paramagnetic lanthanide ion (Ln(3+) ≠ La(3+) , Gd(3+) , Lu(3+) ) within the chelate, the resonance frequencies of exchangeable protons bound to the PARACEST agent are shifted far away from the bulk water frequency. This large chemical shift, combined with an extreme sensitivity to the chemical exchange rate, make PARACEST agents ideally suited for the reporting of significant biological metrics, such as temperature, pH and the presence of metabolites. In addition, the ability to turn PARACEST agents 'off' and 'on' using a frequency-selective saturation pulse gives them a distinct advantage over Gd(3+) -based contrast agents. A current challenge for PARACEST research is the translation of the promising in vitro results into in vivo systems. This short review article first describes the basic theory behind PARACEST contrast agents, their benefits over other contrast agents and their applications to MRI. It then describes some of the recent PARACEST research results: specifically, pH measurements using water molecule exchange rate modulation, T2 exchange contrast caused by water molecule exchange, the use of ultrashort TEs (TE < 10 µs) to overcome T2 exchange line broadening and the potential application of T2 exchange as a new contrast mechanism for MRI. Copyright © 2012 John Wiley & Sons, Ltd.

  1. Model-free nuclear magnetic resonance study of intermolecular free energy landscapes in liquids with paramagnetic Ln3+ spotlights: theory and application to Arg-Gly-Asp.

    Science.gov (United States)

    Fries, Pascal H

    2012-01-28

    We propose an easily applicable method for investigating the pair distribution function of a lanthanide Ln(3+) complex LnL (L = ligand) with respect to any solvent or solute molecule A carrying observable nuclear spins. Let r be the distance of Ln(3+) to the observed nuclear spin I. We derive a simple expression of the experimental value of the configurational average of 1/r(6) in terms of longitudinal paramagnetic relaxation (rate) enhancements (PREs) of the spin I measured on a standard high-resolution NMR spectrometer and due to well-chosen concentrations of LnL complexes in which Ln(3+) is a fast-relaxing paramagnetic lanthanide or the slowly-relaxing gadolinium Gd(3+). The derivation is justified in the general case of a molecule A which is by turns in a bound state where it follows the complex and a free state where it moves independently. It rests on the expression of the underlying PRE theory in terms of the angle-dependent pair distribution function of LnL and A. The simplifications of this theory in the high-field regime and under the condition of fast exchange between bound and free states are carefully discussed. We also show that original information on the angle dependence of the molecular pair distribution function can be gained from the measured paramagnetic dipolar shifts induced by complexed fast-relaxing Ln(3+) ions. The method is illustrated by the case study of the anionic Lnttha(3-) = [Ln(3+)(ttha)](3-) (ttha(6-) = triethylene tetraamine hexacetate) complex interacting with the biologically important tripeptide Arg-Gly-Asp (RGD) which carries peripheral ionic groups. The usefulness of an auxiliary reference outer sphere probe solute is emphasized. © 2012 American Institute of Physics

  2. Separation and estimation of lanthanides using high performance liquid chromatography

    International Nuclear Information System (INIS)

    Datta, Arpita; Sivaraman, N.; Vasudeva Rao, P.R.

    2012-01-01

    The separation efficiency of individual lanthanides depends on the stability constant of the metal-ligand complex. Therefore, stability constant data of lanthanide complexes is important in the development of high performance separation procedures. The dynamic ion exchange HPLC technique was employed at our laboratory to estimate the stability constant of lanthanides with various complexing agents. In these studies, the retention times as well as capacity factors of lanthanides and some actinides were measured as a function of CSA, complexing agent concentrations and mobile phase pH. From these studies, a correlation has been established between capacity factor of a metal ion, concentrations of ion-pairing reagent and complexing agent with the stability constant of lanthanide complex

  3. Experimental solubility measurements of lanthanides in liquid alkalis

    Science.gov (United States)

    Isler, Jeremy; Zhang, Jinsuo; Mariani, Robert; Unal, Cetin

    2017-11-01

    In metallic nuclear fuel, lanthanide fission products play a crucial role in the fuel burnup-limiting phenomena of fuel cladding-chemical interaction (FCCI). The lanthanides have been hypothesized to transport by a 'liquid-like' mechanism out of the metallic fuel to the fuel peripheral to cause FCCI. By liquid fission product cesium and liquid bond sodium, the lanthanides are transported to the peripheral of the fuel through the porosity of the fuel. This work investigates the interaction between the lanthanides and the alkali metals by experimentally measuring the solubility of lanthanides within liquid sodium, and neodymium in liquid cesium and mixtures of cesium and sodium. The temperature dependence of the solubility is experimentally determined within an inert environment. In addition, the dependence of the solubility on the alkali metal concentration in liquid mixtures of cesium and sodium was examined. In quantifying the solubility, the fundamental understanding of this transport mechanism can be better determined.

  4. 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.

  5. Magneto-Optical Properties of Paramagnetic Superrotors

    Science.gov (United States)

    Milner, A. A.; Korobenko, A.; Floß, J.; Averbukh, I. Sh.; Milner, V.

    2015-07-01

    We study the dynamics of paramagnetic molecular superrotors in an external magnetic field. An optical centrifuge is used to create dense ensembles of oxygen molecules in ultrahigh rotational states. In is shown, for the first time, that the gas of rotating molecules becomes optically birefringent in the presence of a magnetic field. The discovered effect of "magneto-rotational birefringence" indicates the preferential alignment of molecular axes along the field direction. We provide an intuitive qualitative model, in which the influence of the applied magnetic field on the molecular orientation is mediated by the spin-rotation coupling. This model is supported by the direct imaging of the distribution of molecular axes, the demonstration of the magnetic reversal of the rotational Raman signal, and by numerical calculations.

  6. Thermal properties of paramagnetic solid helium 3

    International Nuclear Information System (INIS)

    Goldstein, L.

    1983-01-01

    It was shown in recent work that over a limited molar volume range and at asymptotically high temperatures the thermal modulations of the pressure along isochores of paramagnetic solid 3 He could be accounted for through the formalism of the Heisenberg model of an antiferromagnetically interacting localized spin- 1/2 system. The internal consistency of this formalism requires the characteristic exchange-interaction parameter of the model derived from pressure modulation data to be identical with that appearing in the other thermal properties of this quantum solid. In a restricted temperature region where the spin excitations are the dominant thermal excitations of the solid, heat capacity data yield exchange-interaction parameters in fair agreement with those derived from pressures along isochores of larger molar volume. At higher temperatures, within well-defined limitations, thermal excitations involve both spin and phononexcitations. Here, because of the opposite temperature variations of the spin and phonon heat capacity components, the ensuing heat capacity minimum determines exactly the exchange-energy parameter and the relevant limiting Debye temperature as a function of the measured temperature location and value of the heat capacity extremum along the experimentally explored isochore. The exchange-energy parameters so derived display larger deviations from their predicted pressure-based values than those resulting from the lower temperature but still asymptotic spin-only heat capacities. At the present time, ambiguities in the experimental determinations of the characteristic Weiss temperatures of the asymptotic paramagnetic susceptibilities prevent one from deriving exchange-energy parameters with them. The present work leads to the prediction, within the limitations of the model formalism, of thermal properties of magnetized solid 3 He

  7. On kinetics of paramagnetic radiation defects accumulation in beryllium ceramics

    International Nuclear Information System (INIS)

    Polyakov, A.I.; Ryabikin, Yu.A.; Zashkvara, O.V.; Bitenbaev, M.I.; Petykhov, Yu.V.

    1999-01-01

    Results of paramagnetic radiation defects concentration dependence study in beryllium ceramics from gamma-irradiation dose ( 60 Co) within interval 0-100 Mrem are cited. Obtained dose dependence has form of accumulation curve with saturation typical of for majority of solids (crystals, different polymers, organic substances and others) , in which under irradiation occur not only formation of paramagnetic radiation defects, but its destruction due to recombination and interaction with radiation fields. Analysis of accumulation curve by the method of distant asymptotics allows to determine that observed in gamma-irradiated beryllium ceramics double line of electron spin resonance is forming of two types of paramagnetic radiation defects. It was defined, that sum paramagnetic characteristics of beryllium ceramics within 1-100 Mrad gamma- irradiation dose field change insignificantly and define from first type of paramagnetic radiation defects

  8. Separation device of radio lanthanides (DISER)

    International Nuclear Information System (INIS)

    Vera T, A.L.; Monroy G, F.; Vazquez M, J.C.; Jimenez B, F.

    2008-01-01

    At the present time the cancer is one of the main causes of mortality in our country, therefore, its prevention, diagnostic and treatment is of vital importance for those health systems. The treatment of the cancer and other illnesses, starting from monoclonal antibodies, peptides, macro aggregates or marked aminoacids with beta particles emitting radioisotopes, it is an extremely promising field. The radioactive lanthanides: Promethium 149, Terbium 161, Holmium 166 and Lutetium 177 are beta emitting (β), which possess nuclear and chemical properties that have shown their feasibility like radioisotopes of radiotherapeutic use. However, these radioisotopes are not commercially available; to this respect, the Radioactive Materials Research Laboratory (LIMR) of the National Institute of Nuclear Research (ININ), it has developed the methodology of production of these radioisotopes and based on these works, there is designed, built and mounted the Radio lanthanides Separation Device (DISER) able to carry out the radioisotopes production in a routine way. This device is content in a cell that has an auxiliary air service, an extraction system and it is protected with a lead armor-plating of 10 cm. The DISER it is manual and easy of managing. The main function of this equipment is the radio lanthanides separation starting from the extractive chromatography by means of packed columns with a commercial resin (LnSPS) and recovered in the superior and inferior part by fiber glass. The DISER is composed by a main carrousel where the separation columns and the elution recipients are mounted. Also counts with an opening system of irradiation vials, port samples for columns and glass material. The present work presents a detailed description of the DISER, as well as its handling that allows to produce the radioisotopes Promethium-149, Terbium-161, Holmium-166 and Lutetium-177 starting from the separation of its parent elements Neodymium-149, Gadolinium-161, Dysprosium-166 and

  9. 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

  10. 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

  11. Analysis and separation of lanthanide elements

    International Nuclear Information System (INIS)

    Almeida Pimentel, E. de.

    1973-01-01

    Improvements of rare earth separation by the combined use of acetic and critic acid were studied and analytical methods for determining some of the lanthanides were tryed out. Separations of the R.E. studied were favorable when citric acid (solution A) and acetic acid (solution B) were used in the proportion of 10:1 at pH=4,00. Neutron activation, spectro-photometric, polarographic, volumetric and gravimetric procedures allowed the determination of 8 R.E.; samarium, neodymium, praseodymium, lanthanum, cerium, holmium, erbium and europium

  12. Structure and Magnetic Properties of Lanthanide Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Dickerson, James Henry [Vanderbilt Univ., Nashville, TN (United States)

    2014-06-01

    We have had considerable success on this project, particularly in the understanding of the relationship between nanostructure and magnetic properties in lanthanide nanocrystals. We also have successfully facilitated the doctoral degrees of Dr. Suseela Somarajan, in the Department of Physics and Astronomy, and Dr. Melissa Harrison, in the Materials Science Program. The following passages summarize the various accomplishments that were featured in 9 publications that were generated based on support from this grant. We thank the Department of Energy for their generous support of our research efforts in this area of materials science, magnetism, and electron microscopy.

  13. 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.

  14. Three-Dimensional Protein Fold Determination from Backbone Amide Pseudocontact Shifts Generated by Lanthanide Tags at Multiple Sites

    KAUST Repository

    Yagi, Hiromasa

    2013-06-01

    Site-specific attachment of paramagnetic lanthanide ions to a protein generates pseudocontact shifts (PCS) in the nuclear magnetic resonance (NMR) spectra of the protein that are easily measured as changes in chemical shifts. By labeling the protein with lanthanide tags at four different sites, PCSs are observed for most amide protons and accurate information is obtained about their coordinates in three-dimensional space. The approach is demonstrated with the chaperone ERp29, for which large differences have been reported between X-ray and NMR structures of the C-terminal domain, ERp29-C. The results unambiguously show that the structure of rat ERp29-C in solution is similar to the crystal structure of human ERp29-C. PCSs of backbone amides were the only structural restraints required. Because these can be measured for more dilute protein solutions than other NMR restraints, the approach greatly widens the range of proteins amenable to structural studies in solution. © 2013 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Lanthanide light for biology and medical diagnosis

    International Nuclear Information System (INIS)

    Bünzli, Jean-Claude G.

    2016-01-01

    Optical imaging emerges as a vital component of the various techniques needed to meet the stringent requirements of modern bioanalysis and bioimaging. Lanthanide luminescent bioprobes (LLBs) have greatly contributed to this field during the past 35 years because they have definite advantages such as little or no photobleaching and, thanks to time-gated detection, high sensitivity. The review summarizes the numerous tools offered by LLBs under their various forms, coordination compounds, nanoparticles, upconverting nanoparticles and their bioconjugates. It then focuses on biosensing, including point-of-care analysis, and then on both in vitro and in vivo bioimaging with visible and NIR light. The last section compares the performances of LLBs versus those of other commonly used bioprobes (organic dyes, quantum dots, and transition metal complexes). It is concluded that although LLBs will not replace all of existing bioprobes, they add invaluable new specific technologies to the biologist and medical doctor toolboxes. A good deal of improvements are achieved through nanotechnologies, which demonstrates that progresses in biosciences depend on the intersection of different disciplines, photophysics, chemistry, biochemistry, nanotechnology, and materials science. - Highlights: • Lanthanide luminescent bioprobes (LLBs) are indispensable tools in biosciences. • The tools provided by LLBs are summarized. • Main trends in biosensing and point-of-care analysis are presented. • Issues regarding optical bioimaging with visible and NIR light are described. • Characteristics of LLBs, including nanoparticles, are compared to other bioprobes.

  17. Lanthanide light for biology and medical diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Bünzli, Jean-Claude G., E-mail: jean-claude.bunzli@epfl.ch [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 35002 (China); Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2016-02-15

    Optical imaging emerges as a vital component of the various techniques needed to meet the stringent requirements of modern bioanalysis and bioimaging. Lanthanide luminescent bioprobes (LLBs) have greatly contributed to this field during the past 35 years because they have definite advantages such as little or no photobleaching and, thanks to time-gated detection, high sensitivity. The review summarizes the numerous tools offered by LLBs under their various forms, coordination compounds, nanoparticles, upconverting nanoparticles and their bioconjugates. It then focuses on biosensing, including point-of-care analysis, and then on both in vitro and in vivo bioimaging with visible and NIR light. The last section compares the performances of LLBs versus those of other commonly used bioprobes (organic dyes, quantum dots, and transition metal complexes). It is concluded that although LLBs will not replace all of existing bioprobes, they add invaluable new specific technologies to the biologist and medical doctor toolboxes. A good deal of improvements are achieved through nanotechnologies, which demonstrates that progresses in biosciences depend on the intersection of different disciplines, photophysics, chemistry, biochemistry, nanotechnology, and materials science. - Highlights: • Lanthanide luminescent bioprobes (LLBs) are indispensable tools in biosciences. • The tools provided by LLBs are summarized. • Main trends in biosensing and point-of-care analysis are presented. • Issues regarding optical bioimaging with visible and NIR light are described. • Characteristics of LLBs, including nanoparticles, are compared to other bioprobes.

  18. Induced Orbital Paramagnetism and Paratropism in Closed-Shell Molecules

    Science.gov (United States)

    Pelloni, Stefano; Lazzeretti, Paolo; Zanasi, Riccardo

    2009-07-01

    Three-dimensional models of the quantum-mechanical current density induced by a uniform magnetic field in the electron cloud have been obtained for closed-shell systems BeH-, BH, and CH+, characterized by induced orbital paramagnetism, and in planar unsaturated hydrocarbons C4H4 and clamped C8H8, exhibiting π paramagnetism. It is shown that, even for these paramagnetic systems, the paramagnetic contributions to magnetic susceptibilities and nuclear magnetic shielding, customarily taken into account in perturbation theory approaches, can formally be eliminated via the procedure of continuous transformation of the origin of the current density-paramagnetic zero. The definition of magnetic response properties can therefore be recast as a sum of two formally "diamagnetic" terms for any molecule, including systems showing strong induced orbital paramagnetism. It is shown that the paramagnetism in the compounds studied arises from the nodal topology of the electronic wave function. In particular, paratropic vortices circulate about stagnation lines at the intersection of nodal surfaces of the highest-occupied zero-order molecular orbital and corresponding first-order orbital.

  19. Diphenyl-phosphinyl-morpholide (DPPM) lanthanide trifluoroacetate adducts

    International Nuclear Information System (INIS)

    Carvalho, L.R.F. de; Kim, D.J.

    1984-01-01

    Preparation and properties of adducts of lanthanide salts and diphenyl-phosphinyl-morpholide (DPPM) have been described in the literature. Addition compounds containing lanthanide nitrates, isothiocyanates, perchlorates, chlorides, bromides with DPPM have been obtained. In this article, the preparation and characterization of the addition compounds of lanthanide trifluoroacetates (TFA) with DPPM are reported. The compounds of general formula Ln (TFA) 3 . 3DPPM, Ln= La-Lu, Y were characterized by elemental analysis, melting ranges, infrared spectra, absorption and emission visible spectra, X-ray powder patterns. (Author) [pt

  20. Lanthanide-doped upconverting phosphors for bioassay and therapy

    Science.gov (United States)

    Guo, Huichen; Sun, Shiqi

    2012-10-01

    Lanthanide-doped fluorescent materials have gained increasing attention in recent years due to their unique luminescence properties which have led to their use in wide-ranging fields including those of biological applications. Aside from being used as agents for in vivo imaging, lanthanide-doped fluorescent materials also present many advantages for use in bioassays and therapy. In this review, we summarize the applications of lanthanide-doped up-converting phosphors (UCPs) in protein and gene detection, as well as in photodynamic and gene therapy in recent years, and outline their future potential in biological applications. The current report could serve as a reference for researchers in relevant fields.

  1. Lanthanide (III) complexes of 2-(N-salicylideneamino)-4-phenylthiazole

    International Nuclear Information System (INIS)

    Sasidharan, G.N.; Mohanan, K.; Lakshmi Prabha, A.N.

    2002-01-01

    Lanthanide(III) complexes of 2-(N-salicylideneamino)-4- phenylthiazole (HSAT) have been synthesised and characterised by elemental, analytical, thermogravimetric, molar conductance, UV- visible, IR and NMR spectral data. The ligand coordinates to the lanthanide(III) ion in a tridentate fashion without deprotonation, giving complexes of the type [Ln(HSAT) 2 (NO 3 ) 3 ] and [Ln(HSAT) 2 (H 2 0) 3 Cl 3 ]. The spectral data reveal that the ligand is bonded to the lanthanide ion through azomethine nitrogen, ring nitrogen and phenolic oxygen without deprotonation. The nitrate group acts in a bidentate fashion. The ligand and the metal complexes exhibit antibacterial and antifungal activities. (author)

  2. Microstrip resonators for electron paramagnetic resonance experiments

    Science.gov (United States)

    Torrezan, A. C.; Mayer Alegre, T. P.; Medeiros-Ribeiro, G.

    2009-07-01

    In this article we evaluate the performance of an electron paramagnetic resonance (EPR) setup using a microstrip resonator (MR). The design and characterization of the resonator are described and parameters of importance to EPR and spin manipulation are examined, including cavity quality factor, filling factor, and microwave magnetic field in the sample region. Simulated microwave electric and magnetic field distributions in the resonator are also presented and compared with qualitative measurements of the field distribution obtained by a perturbation technique. Based on EPR experiments carried out with a standard marker at room temperature and a MR resonating at 8.17 GHz, the minimum detectable number of spins was found to be 5×1010 spins/GHz1/2 despite the low MR unloaded quality factor Q0=60. The functionality of the EPR setup was further evaluated at low temperature, where the spin resonance of Cr dopants present in a GaAs wafer was detected at 2.3 K. The design and characterization of a more versatile MR targeting an improved EPR sensitivity and featuring an integrated biasing circuit for the study of samples that require an electrical contact are also discussed.

  3. Paramagnetic centers in AlQ3

    International Nuclear Information System (INIS)

    Grecu, M. N.; Mirea, A.; Schwoerer, M.; Grecu, V. V.

    2004-01-01

    Since the discovery in 1987 of its electroluminescent properties, Alq 3 (tris(8-hydroxyquinoline)aluminum(III)) has become one of the most used material in OLEDs (organic light-emitting diodes). Many researches have been carried out for improving its quantum efficiency of light emission. In spite of these, rather many fundamental questions concerning its properties, their dependence on thermal and annealing treatments and crystalline structure remained unanswered. Recently, a significant blue shift of luminescent spectrum of a specially treated fraction (so called δ-phase) has been reported, increasing even more the interest in such a material. In this contribution we shall report on the existence of paramagnetic centers in different Alq 3 fractions formed by using the train sublimation method, as well as in those which have undergone various thermal treatments. Several centers have been observed by cw X- and Q-band EPR spectroscopy, corresponding to spin 1/2 and even spin 3/2. The spin Hamiltonian parameters are given, the temperature dependencies are reported and proposals for model structures are made. (author)

  4. Microstrip resonators for electron paramagnetic resonance experiments.

    Science.gov (United States)

    Torrezan, A C; Mayer Alegre, T P; Medeiros-Ribeiro, G

    2009-07-01

    In this article we evaluate the performance of an electron paramagnetic resonance (EPR) setup using a microstrip resonator (MR). The design and characterization of the resonator are described and parameters of importance to EPR and spin manipulation are examined, including cavity quality factor, filling factor, and microwave magnetic field in the sample region. Simulated microwave electric and magnetic field distributions in the resonator are also presented and compared with qualitative measurements of the field distribution obtained by a perturbation technique. Based on EPR experiments carried out with a standard marker at room temperature and a MR resonating at 8.17 GHz, the minimum detectable number of spins was found to be 5 x 10(10) spins/GHz(1/2) despite the low MR unloaded quality factor Q0=60. The functionality of the EPR setup was further evaluated at low temperature, where the spin resonance of Cr dopants present in a GaAs wafer was detected at 2.3 K. The design and characterization of a more versatile MR targeting an improved EPR sensitivity and featuring an integrated biasing circuit for the study of samples that require an electrical contact are also discussed.

  5. Paramagnetism in ion-implanted oxides

    CERN Document Server

    Mølholt, Torben Esmann; Gíslason, Hafliði Pétur; Ólafsson, Sveinn

    This thesis describes the investigation on para-magnetism in dilute ion-implanted single-crystal oxide samples studied by on- and off-line $^{57}$Fe emission Mössbauer spectroscopy. The ion-implantation of the radioactive isotopes ( $^{57}$Mn and $^{57}$Co) was performed at the ISOLDE facility at CERN in Geneva, Switzerland. The off-line measurements were performed at Aarhus University, Denmark. Mössbauer spectroscopy is a unique method, giving simultaneously local information on valence/spin state of the $^{57}$Fe probe atoms, site symmetry and magnetic properties on an atomic scale. The utilisation of emission Mössbauer spectroscopy opens up many new possibilities compared with traditional transmission Mössbauer spectroscopy. Among them is the possibility of working with a low concentration below 10$^{-4}$ –10$^{-3}$ at.%, where the implanted Mössbauer $^{57}$Fe probes are truly dilute impurities exclusively interacting with their nearest neighbours and therefore the possibility of crea...

  6. Electron paramagnetic resonance dosimetry using synthetic hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwon; Kim, Hwi Young; Ye, Sung Joon [Seoul National University, Seoul (Korea, Republic of); Hirata, Hiroshi [Hokkaido University, Sapporo (Japan); Park, Jong Min [Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-11-15

    The victims exposed doses under 3.5-4.0 Gy have chance to survive if treated urgently. To determine the priority of treatment among a large number of victims, the triage – distinguishing patients who need an urgent treatment from who may not be urgent – is necessary based on radiation biodosimetry. A current gold standard for radiation biodosimetry is the chromosomal assay using human lymphocytes. But this method requires too much time and skilled labors to cover the mass victims in radiation emergencies. Electron paramagnetic resonance (EPR) has been known for its capability of quantifying radicals in matters. EPR dosimetry is based on the measurement of stable radiation-induced radicals in tooth enamel. Hydroxyapatite (HAP) (Ca10(PO4)6(OH)2) contained in tooth enamel is a major probe for radiation dose reconstruction. This HAP dosimetry study was performed using a novel EPR spectrometer in Hokkaido University, Japan. The EPR dose-response curve was made using HAP samples. The blind test using 250 cGy samples showed the feasibility of EPR dosimetry for the triage purpose.

  7. Fragment molecular orbital method for studying lanthanide interactions with proteins

    Energy Technology Data Exchange (ETDEWEB)

    Tsushima, Satoru [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Komeiji, Y. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Mochizuki, Y. [Rikkyo Univ., Tokyo (Japan)

    2017-06-01

    The binding affinity of the calcium-binding protein calmodulin towards Eu{sup 3+} was studied as a model for lanthanide protein interactions in the large family of ''EF-hand'' calcium-binding proteins.

  8. Recovery of uranium and the lanthanides from phosphate rock

    Energy Technology Data Exchange (ETDEWEB)

    Habashi, F; Awadalla, F T; Zailaf, M

    1986-06-01

    A process is proposed for the treatment of phosphate rock for the recovery of uranium and lanthanides. The process assures the production of phosphatic fertilisers without polluting the environment with radioactive material.

  9. Lanthanide-doped luminescent nanomaterials from fundamentals to bioapplications

    CERN Document Server

    Chen, Xueyuan; Tu, Datao

    2014-01-01

    Lanthanide-Doped Luminescent Nanomaterials reviews the latest advances in the development of lanthanide-doped luminescent inorganic nanoparticles for potential bioapplications. This book covers the chemical and physical fundamentals of these nanoparticles, such as the controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in-vitro biodetection of tumor biomarkers. This book is intended for those readers who are interested in systematically understanding the materials design strategy, optical behavior of lanthanide ions, and practical bioapplications of lanthanide nanoparticles. It primarily focuses on the interdisciplinary frontiers in chemistry, physics and biological aspects of luminescent nanomaterials. All chapters were written by scientists active in this field and for a broad audience, providing both beginners and advanced researchers with comprehensive information on the ...

  10. On superfluorescent generation of coherent radiation in a paramagnet

    International Nuclear Information System (INIS)

    Turaev, M.T.; Shumovsky, A.S.

    1988-08-01

    An exact definition is given of a superradiation intensity for a free system and for a system in cavity. The superradiant generation of the Zeeman transitions in proton paramagnet is described. (author). 7 refs, 2 figs

  11. Lanthanide extraction with 2,5-dimethyl-2-hydroxyhexanoic acid

    International Nuclear Information System (INIS)

    Miller, J.H.

    1977-12-01

    This research is concerned with the solvent extraction into chloroform of the lanthanides, using 2,5-dimethyl-2-hydroxyhexanoic acid (DMHHA). This acid is the first α-hydroxy aliphatic acid to be studied as an extracting agent for the lanthanides. The chloroform-water DMHHA partition constant was determined to be 1.0 (at 0.1 M ionic strength and 25 0 C). The acid dimerizes in chloroform with a constant of 56. The light lanthanides can be extracted into chloroform by forming complexes with the DMHHA anions. The extracted metal species is highly aggregated. This extraction has a solubility limit which increases with the addition of unionized acid. The resultant extract is also highly aggregated. At unionized acid-to-metal ratios greater than one, extractions first occur followed by the slow precipitation of the lanthanide. At the tracer level, neodymium is extracted primarily as NdA 3 (HA) 5 and (NdA 3 ) 2 (HA)/sub q/. Very small amounts of (NdA 3 ) 2 and other metal aggregates are also present. The heavy lanthanides do not extract from solutions of DMHHA and its potassium salt, but form aqueous emulsions and precipitates. In the presence of the organic soluble tetrabutylammonium ion the heavy lanthanides can be extracted, presumably as ion pairs. The stability constants of the light lanthanides and DMHHA were determined. The separation factors obtained from DMHHA extractions of the light lanthanides were also investigated and found to be comparable to those obtained employing normal aliphatic carboxylic acid

  12. Dosimetry of ionizing radiations by Electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Azorin N, J.

    2005-01-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  13. Polysulfide coordination clusters of the lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ying-Zhao; Bestgen, Sebastian; Gamer, Michael T.; Roesky, Peter W. [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Konchenko, Sergey N. [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk (Russian Federation); Novosibirsk State University (Russian Federation)

    2017-10-16

    The reaction of [(DippForm){sub 2}Ln(thf){sub 2}] with an excess of elemental sulfur in toluene resulted in the formation of the trinuclear polysulfide coordination clusters [(DippForm){sub 3}Ln{sub 3}S{sub 12}] (Ln=Sm, Yb; DippForm=N,N'-bis(2,6-diisopropylphenyl)formamidinate). These are the first f element coordination clusters (Ln{sub n}S{sub x}) with a larger polysulfide unit (n and x>2). The formation of the coordination clusters can be rationalized by the reductive cleavage of S{sub 8} with divalent lanthanides. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. 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.

  15. Characterization of partitioning relevant lanthanide and actinide complexes by NMR spectroscopy; Charakterisierung von partitioningrelevanten Lanthaniden- und Actinidenkomplexen mittels NMR-Spektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Christian

    2016-01-15

    In the present work the interaction of N-donor ligands, such as 2,6-Bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (nPrBTP) and 2,6-Bis(5-(2,2-dimethylpropyl)1H-pyrazol)-3-yl-pyridine (C5-BPP), with trivalent lanthanide and actinide ions was studied. Ligands of this type show a high selectivity for the separation of trivalent actinide ions over lanthanides from nitric acid solutions. However, the reason for this selectivity, which is crucial for future partitioning and transmutation strategies for radioactive wastes, is still unknown. So far, the selectivity of some N-donor ligands is supposed to be an effect of an increased covalency in the actinide-ligand bond, compared to the lanthanide compounds. NMR spectroscopy on paramagnetic metal complexes is an excellent tool for the elucidation of bonding modes. The overall paramagnetic chemical shift consists of two contributions, the Fermi Contact Shift (FCS), due to electron spin delocalisation through covalent bonds, and the Pseudo Contact Shift (PCS), which describes the dipolar coupling of the electron magnetic moment and the nuclear spin. By assessing the FCS share in the paramagnetic shift, the degree of covalency in the metal-ligand bond can be gauged. Several methods to discriminate FCS and PCS have been used on the data of the nPrBTP- and C5-BPP-complexes and were evaluated regarding their applicability on lanthanide and actinide complexes with N-donor ligands. The study comprised the synthesis of all Ln(III) complexes with the exceptions of Pm(III) and Gd(III) as well as the Am(III) complex as a representative of the actinide series with both ligands. All complexes were fully characterised ({sup 1}H, {sup 13}C and {sup 15}N spectra) using NMR spectroscopy. By isotope enrichment with the NMR-active {sup 15}N in positions 8 and 9 in both ligands, resonance signals of these nitrogen atoms were detected for all complexes. The Bleaneymethod relies on different temperature dependencies for FCS (T{sup -1}) and PCS (T

  16. Electron paramagnetic resonance dosimetry in fingernails

    International Nuclear Information System (INIS)

    Romanyukha, Alex; Benevides, Luis A.; Reyes, Ricardo; Trompier, Francois; Clairand, Isabelle; Swartz, Harold M.

    2008-01-01

    Full text: Based on the capabilities of new instrumentation and the experience gained in the use of teeth for 'after-the-fact' dosimetry, we have undertaken a systematic electron paramagnetic resonance (EPR) study of irradiated fingernails. There have been only a modest number of previous studies of radiation-induced signals in fingernails. While these have given us some promising aspects, overall results have been inconsistent. The most significant problem of EPR fingernail dosimetry is the presence of two signals of non-radiation origin that overlap the radiation-induced signal (RIS), making it almost impossible to do dose measurements below 5 Gy. Historically, these two non-radiation components were named mechanically-induced signal (MIS) and background signal (BKS). In order to investigate them in detail, three different methods of MIS and BKS mutual isolation have been developed and implemented. Having applied these methods, we were able to understand that fingernail tissue, after cut, can be modeled as a deformed sponge, where the MIS and BKS are associated with the stress from elastic and plastic deformations respectively. A sponge has a unique mechanism of mechanical stress absorption, which is necessary for fingernails in order to perform its everyday function of protecting the fingertips from hits and trauma. Like a sponge, fingernails are also known to be an effective water absorber. When a sponge is saturated with water, it tends to restore to its original shape, and when it looses water, it becomes deformed again. The same happens to fingernail tissue. Our suggested interpretation of the mechanical deformation in fingernails gives also a way to distinguish between the MIS and RIS. Obtained results show that the MIS in irradiated fingernails can be almost completely eliminated without a significant change to the RIS by soaking the sample for 10 minutes in water. This is an ongoing study but even at its present state of development, it has shown that it

  17. Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping

    KAUST Repository

    Wang, Feng; Han, Yu; Lim, Chinseong; Lu, Yunhao; Wang, Juan; Xu, Jun; Chen, Hongyu; Zhang, Chun; Hong, Minghui; Liu, Xiaogang

    2010-01-01

    or hexagonal) and upconversion emission colour (green to blue) through use of trivalent lanthanide dopant ions introduced at precisely defined concentrations. We use first-principles calculations to confirm that the influence of lanthanide doping on crystal

  18. Electronic, magnetic, and magnetocrystalline anisotropy properties of light lanthanides

    Science.gov (United States)

    Hackett, Timothy A.; Baldwin, D. J.; Paudyal, D.

    2017-11-01

    Theoretical understanding of interactions between localized and mobile electrons and the crystal environment in light lanthanides is important because of their key role in much needed magnetic anisotropy in permanent magnet materials that have a great impact in automobile and wind turbine applications. We report electronic, magnetic, and magnetocrystalline properties of these basic light lanthanide elements studied from advanced density functional theory (DFT) calculations. We find that the inclusion of onsite 4f electron correlation and spin orbit coupling within the full-potential band structure is needed to understand the unique magnetocrystalline properties of these light lanthanides. The onsite electron correlation, spin orbit coupling, and full potential for the asphericity of charge densities must be taken into account for the proper treatment of 4f states. We find the variation of total energy as a function of lattice constants that indicate multiple structural phases in Ce contrasting to a single stable structure obtained in other light lanthanides. The 4f orbital magnetic moments are partially quenched as a result of crystalline electric field splitting that leads to magnetocrystalline anisotropy. The charge density plots have similar asphericity and environment in Pr and Nd indicating similar magnetic anisotropy. However, Ce and Sm show completely different asphericity and environment as both orbital moments are significantly quenched. In addition, the Fermi surface structures exemplified in Nd indicate structural stability and unravel a cause of anisotropy. The calculated magnetocrystalline anisotropy energy (MAE) reveals competing c-axis and in-plane anisotropies, and also predicts possibilities of unusual structural deformations in light lanthanides. The uniaxial magnetic anisotropy is obtained in the double hexagonal closed pack structures of the most of the light lanthanides, however, the anisotropy is reduced or turned to planar in the low symmetry

  19. In vivo imaging of a stable paramagnetic probe by pulsed-radiofrequency electron paramagnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Murugesan; Cook; Devasahayam

    1997-01-01

    , Recent advances in radiofrequency (RF) electronics have enabled the generation of pulses of the order of 10-50 ns. Such short pulses provide adequate spectral coverage for EPR studies at 300 MHz resonant frequency. Acquisition of free induction decays (FID) of paramagnetic species possessing...... inhomogeneously broadened narrow lines after pulsed excitation is feasible with an appropriate digitizer/averager. This report describes the use of time-domain RF EPR spectrometry and imaging for in vivo applications. FID responses were collected from a water-soluble, narrow line width spin probe within phantom...... samples in solution and also when infused intravenously in an anesthetized mouse. Using static magnetic field gradients and back-projection methods of image reconstruction, two-dimensional images of the spin-probe distribution were obtained in phantom samples as well as in a mouse. The resolution...

  20. Trends in metallo-organic chemistry of scandium, yttrium, and the lanthanides

    International Nuclear Information System (INIS)

    Singh, A.

    1994-01-01

    Several interesting aspects of the metallo-organic chemistry of group 3 and the lanthanides have been highlighted, which include: (a) the chemistry of a few notable organolanthanide compounds, alkoxo and aryloxo derivatives derived from sterically demanding ligands, (b) new trends in the chemistry of lanthanide heterometallic alkoxides, (c) an account of zero valent organometallics of yttrium and the lanthanides, and (d) aspects of agostic interactions in the lanthanide metallo-organic compounds. (author). 49 refs

  1. Lanthanide-doped nanoparticles as the active optical medium in polymer-based devices

    NARCIS (Netherlands)

    Stouwdam, J.W.

    2004-01-01

    The luminescence of lanthanide ions in organic environment is greatly reduced compared to inorganic materials. This thesis describes the doping of the lanthanide ions in the core of inorganic nanoparticles that are soluble in organic solvents as a way to shield the lanthanide ions from the organic

  2. Calorimetric approach of lanthanides (3) complexation and extraction by malonamides

    International Nuclear Information System (INIS)

    Flandin, J.L.

    2001-01-01

    In the field of long lived radionuclides separation, diamides are interesting extractants because of their ability to co-extract trivalent lanthanides and actinides, which is a preliminary and essential step in high level radioactive waste reprocessing. The research carried out contributes to a better understanding of the mechanisms and the aim is the determination of thermodynamics properties (Δ r G, Δ r H et Δ r S) related to the complexation and the extraction of lanthanides(III) by malonamides. The first part of the document deals with the complexation of lanthanides(III) by an hydrosoluble diamide. The experimental results obtained by UV-visible spectrometry, TRLIF, NMR and microcalorimetric titration proved that lanthanides(III)-TEMA interactions in aqueous medium are very weak and that the complexation reaction is endothermic. The TEMA ligand still stays in the second coordination sphere of coordination of the lanthanide ion. The second part of this study focuses on the extraction of neodymium(III) nitrate by a lipophilic diamide which is an exothermic reaction. The influence of the composition of aqueous and organic phases on the thermodynamics properties Δ r G et Δ r H has been studied by microcalorimetric titration. The most influent parameter is the total concentration in extractant. As a consequence, thermodynamic values are very dependent on the organic phase organisation before and alter extraction. At the same time, this study showed the interest of the calorimetric approach for the analysis of basic reactions like diamide dilution and their organisation as oligomeric aggregates. (author)

  3. High performance separation of lanthanides and actinides

    International Nuclear Information System (INIS)

    Sivaraman, N.; Vasudeva Rao, P.R.

    2011-01-01

    The major advantage of High Performance Liquid Chromatography (HPLC) is its ability to provide rapid and high performance separations. It is evident from Van Deemter curve for particle size versus resolution that packing materials with particle sizes less than 2 μm provide better resolution for high speed separations and resolving complex mixtures compared to 5 μm based supports. In the recent past, chromatographic support material using monolith has been studied extensively at our laboratory. Monolith column consists of single piece of porous, rigid material containing mesopores and micropores, which provide fast analyte mass transfer. Monolith support provides significantly higher separation efficiency than particle-packed columns. A clear advantage of monolith is that it could be operated at higher flow rates but with lower back pressure. Higher operating flow rate results in higher column permeability, which drastically reduces analysis time and provides high separation efficiency. The above developed fast separation methods were applied to assay the lanthanides and actinides from the dissolver solutions of nuclear reactor fuels

  4. Paramagnetic centers in nanocrystalline TiC/C system

    International Nuclear Information System (INIS)

    Guskos, N.; Bodziony, T.; Maryniak, M.; Typek, J.; Biedunkiewicz, A.

    2008-01-01

    Electron paramagnetic resonance is applied to study the defect centers in nanocrystalline titanium carbide dispersed in carbon matrix (TiC x /C) synthesized by the non-hydrolytic sol-gel process. The presence of Ti 3+ paramagnetic centers is identified below 120 K along with a minor contribution from localized defect spins coupled with the conduction electron system in the carbon matrix. The temperature dependence of the resonance intensity of the latter signal indicates weak antiferromagnetic interactions. The presence of paramagnetic centers connected with trivalent titanium is suggested to be the result of chemical disorder, which can be further related to the observed anomalous behavior of conductivity, hardness, and corrosion resistance of nanocrystalline TiC x /C

  5. Paramagnetic resonance and electronic conduction in organic semiconductors

    International Nuclear Information System (INIS)

    Nechtschein, M.

    1963-01-01

    As some organic bodies simultaneously display semi-conducting properties and a paramagnetism, this report addresses the study of conduction in organic bodies. The author first briefly recalls how relationships between conductibility and Electron Paramagnetic Resonance (EPR) can be noticed in a specific case (mineral and metallic semiconductors). He discusses published results related to paramagnetism and conductibility in organic bodies. He reviews various categories of organic bodies in which both properties are simultaneously present. He notably addresses radical molecular crystals, non-radical molecular crystals, charge transfer complexes, pyrolyzed coals, and pseudo-ferromagnetic organic structures. He discusses the issue of relationships between conduction (charge transfer by electrons) and ERP (which reveals the existence of non-paired electrons which provide free spins)

  6. Synthesis and characterization of lanthanide picrate complexes with 4-picoline-N-oxide (4-pic N O)

    International Nuclear Information System (INIS)

    Silva, E.M. da.

    1991-01-01

    The lanthanide picrate complexes with 4-picoline-N-oxide were obtained from ethanolic solutions of the hydrated lanthanide picrate and the ligand. The lanthanide content was determined by complexometric titration with EDTA. Carbon, Nitrogen and Hydrogen were determined by microanalytical procedures. Chemical analysis of the lanthanide picrate complexes are also presented. (author)

  7. Intrinsic Electric Dipole Moments of Paramagnetic Atoms: Rubidium and Cesium

    OpenAIRE

    Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.

    2008-01-01

    The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar--pseudo-scalar (S-PS) electron-nucleus interactions. The electron EDM and the S-PS EDM contribution to atomic EDM scales as Z^3. Thus, the heavy paramagnetic atomic systems will exhibit large enhancement factors. However, the nature of the coupling is so small that it becomes an interest of high precision atomic experiments. In this work, we...

  8. A paramagnetic nearly isodynamic compact magnetic confinement system

    International Nuclear Information System (INIS)

    Cooper, W.A.; Antonietti, J.M.; Todd, T.N.

    2001-01-01

    A coreless compact magnetic confinement system that consists of sets of helical windings and vertical magnetic field coils is investigated. The helical coils produce a small toroidal translation of the magnetic field lines and seed paramagnetism. The force-free component of the toroidal current strongly enhances the paramagnetism such that isodynamic conditions near the plasma centre can be approached. At β 5%, the configuration is stable to local MHD modes. Global MHD modes limit the toroidal current 2πJ to about 60kA for peaked J. Bootstrap-like hollow current profiles generate quasiaxisymmetric systems that require a close fitting conducting shell to satisfy external kink stability. (author)

  9. Modified Sucksmith balances for ferromagnetic and paramagnetic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lundquist, N; Myers, H P

    1962-02-15

    Two balances, one for measurement of ferromagnetic magnetisation, the other for paramagnetic susceptibility measurements, are described. Designs are based on Sucksmith's ring balance but the ring and optical lever system of the latter has been replaced by a strain gauge bridge, which allows the force on the magnetic specimens to be determined via potentiometer readings. The modified balances are very robust, insensitive to vibration and, if desired, suitable for direct recording. Relative accuracies of 0.3 % and 0.5 % are obtained respectively for the ferromagnetic and paramagnetic systems.

  10. Probing Spin Crossover in a Solution by Paramagnetic NMR Spectroscopy.

    Science.gov (United States)

    Pavlov, Alexander A; Denisov, Gleb L; Kiskin, Mikhail A; Nelyubina, Yulia V; Novikov, Valentin V

    2017-12-18

    Spin transitions in spin-crossover compounds are now routinely studied in the solid state by magnetometry; however, only a few methods exist for studies in solution. The currently used Evans method, which relies on NMR spectroscopy to measure the magnetic susceptibility, requires the availability of a very pure sample of the paramagnetic compound and its exact concentration. To overcome these limitations, we propose an alternative NMR-based technique for evaluating spin-state populations by only using the chemical shifts of a spin-crossover compound; those can be routinely obtained for a solution that contains unknown impurities and paramagnetic admixtures or is contaminated otherwise.

  11. Determination of stability constants of lanthanide complexes with tetracycline

    International Nuclear Information System (INIS)

    Saiki, Mitiko

    1975-01-01

    The stability constants of complexes compounds formed with tetracycline and lanthanides elements were determined for all lanthanides except promethium. The experimental procedure used was solvent extraction of the lanthanides labelled with their radioactive isotopes. It was shown that the formed complexes are mononuclear and that no hydroxo complexes or negatively charged complexes are formed in the experimental conditions of this work. Four methods of calculation were used for all complexes studied: the method of the average number of ligands, the method of limiting value, the method of two parameters and the method of weighted least squares. A comparison was made of the graphical methods with the method of least squares, showing the convenience of preceding least squares calculation by the graphical methods, in order to verify eventual mistakes of numerical data. It was shown the advantage of using radioisotopes of the elements for such a study, specially if the solvent extraction technique is used to-get the experimental data. (author)

  12. Lanthanide and actinide complexation studies with tetradentate 'N' donor ligands

    International Nuclear Information System (INIS)

    Bhattacharyya, A.; Mohapatra, M.; Mohapatra, P.K.; Rawat, N.; Tomar, B.S.; Gadly, T.; Ghosh, S.K.; Manna, D.; Ghanty, T.K.

    2014-01-01

    Because of their similar charge and chemical behaviour separation of trivalent actinides and lanthanides is an important and challenging task in nuclear fuel cycle. Soft (S,N) donor ligands show selectivity towards the trivalent actinides over the lanthanides. Out of various 'N' donor ligands studied, bis(1,2,4)triazinyl bipyridine (BTBP) and bis(1,2,4)triazinyl phenanthroline (BTPhen) were found to be most promising. In order to understand the separation behaviour of these ligands, their complexation studies with these 'f' block elements are essential. In the present work, complexation studies of various lanthanide ions (La 3+ , Eu 3+ and Er 3+ ) was studied with ethyl derivatives of BTBP (C 2 BTBP) and BTBPhen (C 2 BTPhen) and pentyl derivative of BTBP (C 5 BTBP) in acetonitrile medium using UV-Vis spectrophotometry, fluorescence spectroscopy and solution calorimetry. Computational studies were also carried out to understand the experimental results

  13. The electronic structure of the lanthanides and actinides, a comparison

    International Nuclear Information System (INIS)

    Edelstein, N.M.

    1998-01-01

    Full text: Optical spectra of the two f-element series (the lanthanides and actinides) are comparable in many respects. For the trivalent ions isolated in single crystals, both series exhibit rich, narrow line spectra. These data can be analysed in terms of a parametric model based on a free-ion Hamiltonian plus the addition of a crystal field Hamiltonian. For most systems the agreement between the calculated and experimental energy levels is quite good. In the actinide series there appears to be a correlation between the magnitude of the crystal field and the inadequacy of the fits. The early actinides exhibit multiple oxidation states for which there is no precedent in the lanthanide series. The parametric model mentioned earlier has been utilized for some tetravalent actinide systems with reasonably good results. A selective survey of results describing the similarities and differences of various lanthanide and actinide systems will be given

  14. 'Americium(III)/trivalent lanthanides' separation using organothiophosphinic acids

    International Nuclear Information System (INIS)

    Hill, C.; Madic, C.; Baron, P.; Ozawa, Masaki; Tanaka, Yasumasa.

    1997-01-01

    The present paper describes the extraction of neodymium and other lanthanides by saponified Cyanex 301 acid. The saponification of commercial Cyanex 301 acid favoured the extraction of macro concentrations of neodymium from sodium nitrate aqueous solutions (pH eq ∼ 4). The amount of lanthanide extracted in the organic phase always reached the third of the initial concentration of saponified Cyanex 301 acid, which assumed a cation exchange mechanism to occur during the extraction. No nitrate anion took part in the complex formation. This paper also compares the abilities of purified Cyanex 301, Cyanex 302 and Cyanex 272 acids to extract and separate 241 Am(III) from 152 Eu(III). Very high separation factors S.F. Am/Eu were observed in the case of purified Cyanex 301 acid. Finally some studies are presented herein using tri-n-butylphosphate (TBP) as a synergistic extractant with Cyanex 301 acid to separate actinides from trivalent lanthanide. (author)

  15. Separation of lanthanides using micro solvent extraction system

    International Nuclear Information System (INIS)

    Nishihama, S.; Tajiri, Y.; Yoshizuka, K.

    2006-01-01

    A micro solvent extraction system for the separation of lanthanides has been investigated. The micro flow channel is fabricated on a poly(methyl methacrylate) (PMMA) plate, and solvent extraction progresses by feeding aqueous and organic solutions into the channel simultaneously. The extraction equilibrium is quickly achieved, without any mechanical mixing, when a narrow channel (100 μm width and 100 μm depth) is used. The results of solvent extraction from the Pr/Nd and Pr/Sm binary solutions revealed that both lanthanides are firstly extracted together, and then, the lighter lanthanide extracted in the organic solution alternatively exchanges to the heavier one in the aqueous solution to achieve the extraction equilibrium. The phase separation of the aqueous and organic phases after extraction can also be successively achieved by contriving the cross section of the flow channel, and the extractive separation of Pr/Sm is demonstrated. (authors)

  16. Optical, Structural and Paramagnetic Properties of Eu-Doped Ternary Sulfides ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y

    Directory of Open Access Journals (Sweden)

    Vítězslav Jarý

    2015-10-01

    Full Text Available Eu-doped ternary sulfides of general formula ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y are presented as a novel interesting material family which may find usage as X-ray phosphors or solid state white light emitting diode (LED lighting. Samples were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, time-resolved photoluminescence spectroscopy, electron paramagnetic resonance, and X-ray excited fluorescence. Corresponding characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra, and decay kinetics curves, were measured and evaluated in a broad temperature range (8–800 K. Calculations including quantum local crystal field potential and spin-Hamiltonian for a paramagnetic particle in D3d local symmetry and phenomenological model dealing with excited state dynamics were performed to explain the experimentally observed features. Based on the results, an energy diagram of lanthanide energy levels in KLuS2 is proposed. Color model xy-coordinates are used to compare effects of dopants on the resulting spectrum. The application potential of the mentioned compounds in the field of white LED solid state lighting or X-ray phosphors is thoroughly discussed.

  17. Thermodynamical properties of liquid lanthanides-A variational approach

    Energy Technology Data Exchange (ETDEWEB)

    Patel, H. P. [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India); Thakor, P. B., E-mail: pbthakor@rediffmail.com [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Sonvane, Y. A. [Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India)

    2015-06-24

    Thermodynamical properties like Entropy (S), Internal energy (E) and Helmholtz free energy (F) of liquid lanthanides using a variation principle based on the Gibbs-Bogoliubuv (GB) inequality with Percus Yevick hard sphere reference system have been reported in the present investigation. To describe electron-ion interaction we have used our newly constructed parameter free model potential along with Sarkar et al. local field correction function. Lastly, we conclude that our newly constructed model potential is capable to explain the thermodynamical properties of liquid lanthanides.

  18. Microwave synthesis of nanostructured oxide sorbents doped with lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Mitrofanov, Andrey A., E-mail: mitrofanov-a@icloud.com; Silyavka, Elena S.; Shilovskikh, Vladimir V.; Kolonitckii, Petr D.; Sukhodolov, Nikolai G.; Selyutin, Artem A., E-mail: selutin@inbox.ru [Saint Petersburg State University, 7/9, Universitetskaya nab., St. Petersburg, 199034 (Russian Federation)

    2016-06-17

    A number of nanostructured mesoporous oxide systems based on aluminum oxide, doped with lanthanide ions have been obtained in this study. Structure and morphology of oxides obtained have been examined by X-ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy. The surface area of the samples was determined by the BET method. The dependence of the adsorption of insulin on synthesized oxides from the concentration was investigated. The containing of insulin in solutions after adsorption was determined by the Bradford method. The isotherms of adsorption of insulin on resulting oxide sorbents were plotted, the dependence capacity of the sorption of insulin from the lanthanide dopant was determined.

  19. Electrospray mass spectrometry for actinides and lanthanide speciation

    International Nuclear Information System (INIS)

    Moulin, C.; Amekraz, B.; Colette, S.; Doizi, D.; Jacopin, C.; Lamouroux, C.; Plancque, G.

    2006-01-01

    Electrospray mass spectrometry (ES-MS) is a new speciation technique that has the great interest to be able to probe the element, the ligand and the complex in order to reach the speciation. This paper will focus on the use of ES-MS for the speciation of actinides/lanthanides on several systems of interest in various fields such as the interaction between DTPA (decorporant) and europium, HEBP and uranium, BTP (new extracting agent) and lanthanides with comparison with known chemistry as well as whenever possible with other speciation techniques

  20. Separation of lanthanides through hydroxyapatite; Separacion de lantanidos mediante hidroxiapatita

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, F.G

    2006-07-01

    With the objective of obtaining from an independent way to each one of the lanthanides {sup 151} Pm, {sup 161} Tb, {sup 166} Ho and {sup 177} Lu free of carrier and with high specific activities starting from the indirect irradiation via, it intends in this work to determine the viability of separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu, by means of ion exchange column chromatography, using hydroxyapatite (HAp) and fluorite like absorbent material in complexing media. It is important to mention that have registered separation studies among lanthanides of the heavy group with those of the slight group, using the same mass and, in comparison with this work, quantities different from the father were used and of the son, also, that the separation studies were carried out among neighboring lanthanides. In this investigation, it was determined the effect that its have the complexing media: KSCN, sodium tartrate, sodium citrate, EDTA and aluminon, their pH and concentration, in the adsorption of the lanthanides in both minerals, in order to determine the chromatographic conditions for separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu. The work consists of five chapters, in the first one they are presented a theoretical introduction of the characteristics more important of the lanthanides, the hydroxyapatite and the fluorite; in the second, it is deepened in the ion exchange, as well as the two techniques (XRD and High Vacuum Electron Microscopy) to make the characterization of LnCI{sub 3} (Ln = Nd, Gd, Dy or Yb) synthesized. The third chapter, it describes the methodology continued in our experimental work; in the room, its are presented the obtained results of the static and dynamic method to determine the viability of separation of neighboring lanthanides; and finally, the five chapter shows the conclusions. In this study, it is concludes that the separation among neighboring lanthanides cannot be carried out in the minerals and used media; because

  1. SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

    Science.gov (United States)

    Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

    1962-08-14

    A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

  2. Characterization and thermogravimetric analysis of lanthanide hexafluoroacetylacetone chelates.

    Science.gov (United States)

    Shahbazi, Shayan; Stratz, S Adam; Auxier, John D; Hanson, Daniel E; Marsh, Matthew L; Hall, Howard L

    2017-01-01

    This work reports the thermodynamic characterizations of organometallic species as a vehicle for the rapid separation of volatile nuclear fission products via gas chromatography due to differences in adsorption enthalpy. Because adsorption and sublimation thermodynamics are linearly correlated, there is considerable motivation to determine sublimation enthalpies. A method of isothermal thermogravimetric analysis, TGA-MS and melting point analysis are employed on thirteen lanthanide 1,1,1,5,5,5-hexafluoroacetylacetone complexes to determine sublimation enthalpies. An empirical correlation is used to estimate adsorption enthalpies of lanthanide complexes on a quartz column from the sublimation data. Additionally, four chelates are characterized by SC-XRD, elemental analysis, FTIR and NMR.

  3. A protocol for the refinement of NMR structures using simultaneously pseudocontact shift restraints from multiple lanthanide ions

    Energy Technology Data Exchange (ETDEWEB)

    Sala, Davide; Giachetti, Andrea; Luchinat, Claudio, E-mail: luchinat@cerm.unifi.it; Rosato, Antonio, E-mail: rosato@cerm.unifi.it [University of Florence, Magnetic Resonance Center (CERM) (Italy)

    2016-11-15

    The binding of paramagnetic metal ions to proteins produces a number of different effects on the NMR spectra of the system. In particular, when the magnetic susceptibility of the metal ion is anisotropic, pseudocontact shifts (PCSs) arise and can be easily measured. They constitute very useful restraints for the solution structure determination of metal-binding proteins. In this context, there has been great interest in the use of lanthanide(III) ions to induce PCSs in diamagnetic proteins, e.g. through the replacement native calcium(II) ions. By preparing multiple samples in each of which a different ion of the lanthanide series is introduced, it is possible to obtain multiple independent PCS datasets that can be used synergistically to generate protein structure ensembles (typically called bundles). For typical NMR-based determination of protein structure, it is necessary to perform an energetic refinement of such initial bundles to obtain final structures whose geometric quality is suitable for deposition in the PDB. This can be conveniently done by using restrained molecular dynamics simulations (rMD) in explicit solvent. However, there are no available protocols for rMD using multiple PCS datasets as part of the restraints. In this work, we extended the PCS module of the AMBER MD package to handle multiple datasets and tuned a previously developed protocol for NMR structure refinement to achieve consistent convergence with PCS restraints. Test calculations with real experimental data show that this new implementation delivers the expected improvement of protein geometry, resulting in final structures that are of suitable quality for deposition. Furthermore, we observe that also initial structures generated only with traditional restraints can be successfully refined using traditional and PCS restraints simultaneously.

  4. Dynamical magnetic response of paramagnetic CeFe-2

    International Nuclear Information System (INIS)

    Rainford, B.D.; McK Paul, D.; Warwick Univ., Coventry

    1988-01-01

    Inelastic neutron scattering has been used to study the energy dependence of the paramagnetic response from CeFe 2 . Our results, when integrated over energy, are in excellent agreement with the polarised neutron experiments of Deportes et al., but the correlation length obtained by fitting the data to a double Lorentzian scattering function is significantly smaller than that derived previously

  5. Intrinsic electric dipole moments of paramagnetic atoms : Rubidium and cesium

    NARCIS (Netherlands)

    Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.

    2008-01-01

    The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar-pseudoscalar (S-PS) electron-nucleus interaction. The electron EDM and the S-PS contributions to the EDMs of these atoms scale as approximate to

  6. Introduction to Spin Label Electron Paramagnetic Resonance Spectroscopy of Proteins

    Science.gov (United States)

    Melanson, Michelle; Sood, Abha; Torok, Fanni; Torok, Marianna

    2013-01-01

    An undergraduate laboratory exercise is described to demonstrate the biochemical applications of electron paramagnetic resonance (EPR) spectroscopy. The beta93 cysteine residue of hemoglobin is labeled by the covalent binding of 3-maleimido-proxyl (5-MSL) and 2,2,5,5-tetramethyl-1-oxyl-3-methyl methanethiosulfonate (MTSL), respectively. The excess…

  7. Some examples of utilization of electron paramagnetic resonance in biology

    International Nuclear Information System (INIS)

    Bemski, G.

    1982-10-01

    A short outline of the fundamentals of electron paramagnetic resonance (EPR) is presented and is followed by examples of the application of EPR to biology. These include use of spin labels, as well as of ENDOR principally to problems of heme proteins, photosynthesis and lipids. (Author) [pt

  8. WOHLLEBEN EFFECT (PARAMAGNETIC MEISSNER EFFECT) IN HIGH-TEMPERATURE SUPERCONDUCTORS

    NARCIS (Netherlands)

    KHOMSKII, D

    Recently a quite unexpected phenomenon was observed during the study of the magnetic properties of High-T(c) superconductors: In the field-cooled regime the magnetic response of some HTSC at very low fields (less than or similar to 1 Oe), instead of being diamagnetic, becomes paramagnetic. Such

  9. Magnon spin Hall magnetoresistance of a gapped quantum paramagnet

    NARCIS (Netherlands)

    Ulloa, Camilo; Duine, R.A.

    2018-01-01

    Motivated by recent experimental work, we consider spin transport between a normal metal and a gapped quantum paramagnet. We model the latter as the magnonic Mott-insulating phase of an easy-plane ferromagnetic insulator. We evaluate the spin current mediated by the interface exchange coupling

  10. A direct simulation method for flows with suspended paramagnetic particles

    NARCIS (Netherlands)

    Kang, T.G.; Hulsen, M.A.; Toonder, den J.M.J.; Anderson, P.D.; Meijer, H.E.H.

    2008-01-01

    A direct numerical simulation method based on the Maxwell stress tensor and a fictitious domain method has been developed to solve flows with suspended paramagnetic particles. The numerical scheme enables us to take into account both hydrodynamic and magnetic interactions between particles in a

  11. Nonequilibrium ensembles. 3. Spin 1/2 paramagnets

    International Nuclear Information System (INIS)

    Sobouti, Y.; Khajeh-Pour, M.R.H.

    1990-07-01

    The thermodynamic state of a paramagnetic substance in which the spin vectors precess coherently is investigated. The state is a time dependent one. The corresponding density matrix and the thermodynamics emerging from it is worked out. A laboratory preparation of such a system is discussed. (author). 3 refs

  12. Dynamics in photosynthetic transient complexes studied by paramagnetic NMR spectroscopy

    NARCIS (Netherlands)

    Scanu, Sandra

    2013-01-01

    This PhD thesis focuses on fundamental aspects of protein-protein interactions. A multidisciplinary methodology for the detection and visualization of transient, lowly-populated encounter protein complexes is described. The new methodology combined paramagnetic NMR spectroscopy with computational

  13. Investigation of paramagnetic saturation in lanthanum manganese nitrate

    NARCIS (Netherlands)

    Flokstra, Jakob; Meijer, H.C.; Bots, G.J.C.; Verheij, W.A.; van der Marel, L.C.

    1973-01-01

    Paramagnetic saturation of lanthanum manganese nitrate, La2Mn3(NO3)12·24H2O, has been investigated at liquid He temperatures in a static as well as a dynamical way. With the aid of the molecular-field theory the Casimir and Du Pré dispersion and absorption curves are adapted explicitly to the

  14. Correlation induced paramagnetic ground state in FeAl

    Czech Academy of Sciences Publication Activity Database

    Mohn, P.; Persson, C.; Blaha, P.; Schwarz, K.; Novák, Pavel; Eschrig, H.

    2001-01-01

    Roč. 87, č. 19 (2001), s. 196401-1-196401-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z1010914 Keywords : FeAl * paramagnetic ground state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001

  15. New possibilities for using laser polarimetry technology to study electron paramagnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, E V; Zapasskii, V S

    1982-01-01

    Optical methods of recording electron paramagnetic resonance which arose in the early 50's as applied to the problem of recording the magnetic resonance of excited atoms is at the present time widely used in studying the electron paramagnetic resonance of the ground and excited states of free atoms and paramagnetic centers in condensed media. At the present time attention is devoted to the additional possibilities of optical methods of electron paramagnetic resonance which are realized using laser sources.

  16. On the suitability of lanthanides as actinide analogs

    International Nuclear Information System (INIS)

    Raymond, Kenneth; Szigethy, Geza

    2008-01-01

    With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries. (authors)

  17. Filled buckyballs: recent developments from the endohedral metallofullerenes of lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Edelmann, F T [Magdeburg Univ. (Germany). Chemisches Inst.

    1995-05-15

    Metal-containing fullerenes - an intensively studied area of research. Recent developments in the field of endohedral metallofullerenes of lanthanides and the perspectives these results provide for the future are discussed herein. An additional theme is the specific incorporation of metal salts in carbon nanotubes, relatives of fullerenes, which Green et al. reported recently. (orig.)

  18. Lanthanide Lewis acid-mediated enantioselective conjugate radical additions.

    Science.gov (United States)

    Sibi, Mukund P; Manyem, Shankar

    2002-08-22

    [reaction: see text] Lanthanide triflates along with proline-derived ligands have been found to be efficient catalysts for enantioselective conjugate addition of nucleophilic radicals to enoates. N-Acyl oxazolidinones, when used as achiral additives, gave meaningful enhancements in the ees for the product.

  19. Lanthanide(III) Complexes with Tridentate Schiff Base Ligand ...

    African Journals Online (AJOL)

    Lanthanide complexes, hydrazino, antioxidant activity, X-ray structure. 1. Introduction ... measured using a Johnson Matthey scientific magnetic suscepti- bility balance. 2.1. .... of the ligand and that the nitrogen atom supporting this proton is not involved in the ... 4f-electrons are not involved in the coordination. These facts.

  20. Influencing fatty acid composition of yeasts by lanthanides

    Czech Academy of Sciences Publication Activity Database

    Kolouchová, I.; Sigler, Karel; Zimola, M.; Řezanka, Tomáš; Matatková, O.; Masák, J.

    2016-01-01

    Roč. 32, č. 8 (2016), s. 126 ISSN 0959-3993 R&D Projects: GA ČR GA14-00227S Institutional support: RVO:61388971 Keywords : Fatty acids * Lanthanides * Microbial lipids Subject RIV: EE - Microbiology, Virology Impact factor: 1.658, year: 2016

  1. Synthetic approaches to lanthanide complexes with tetrapyrrole type ligands

    International Nuclear Information System (INIS)

    Pushkarev, V E; Tomilova, L G; Tomilov, Yu V

    2008-01-01

    Approaches to the synthesis of single-, double- and triple-decker complexes of lanthanides with phthalocyanines and their analogues known to date are considered. Examples of preparation of sandwich-type complexes based on other metals of the Periodic system are given.

  2. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Anstey, Mitchell R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Buckley, Heather L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arnold, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  3. Sol–gel preparation of selected lanthanide aluminium garnets

    Czech Academy of Sciences Publication Activity Database

    Dubnikova, N.; Garskaite, E.; Pinkas, J.; Bezdička, Petr; Beganskiene, A.; Kareiva, A.

    2010-01-01

    Roč. 55, č. 2 (2010), s. 213-219 ISSN 0928-0707 Institutional research plan: CEZ:AV0Z40320502 Keywords : lanthanide aluminium garnets * sol-gel processing Subject RIV: CA - Inorganic Chemistry Impact factor: 1.525, year: 2010

  4. Addition compounds of yttrium and lanthanide perrhenates with tetramethylene sulphoxide

    International Nuclear Information System (INIS)

    Umeda, K.

    1977-01-01

    Adducts of lanthanide perrhenates with tetramethylene sulfoxide are prepared and characterized. The compounds having as general formula Ln(Re04) 3 .7.5 TMSO(ln=La-Lu and Y) are characterized by elemental analysis, infrared spectra, molar conductance measurements, x-ray powder patterns, differential scanning calorimetry curves, melting temperature range measurements and thermogravimetric analysis [pt

  5. Studies of lanthanide complexes by a combination of spectroscopic methods

    Czech Academy of Sciences Publication Activity Database

    Krupová, Monika; Bouř, Petr; Andrushchenko, Valery

    2015-01-01

    Roč. 22, č. 1 (2015), s. 44 ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /13./. 19.03.2015-21.03.2015, Nové Hrady] Institutional support: RVO:61388963 Keywords : lanthanide complexes * chirality sensing * chirality amplification * spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry

  6. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Lippuner, Jonas; Roberts, Luke F., E-mail: jlippuner@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, MC 350-17, 1200 E California Boulevard, Pasadena CA 91125 (United States)

    2015-12-20

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  7. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    International Nuclear Information System (INIS)

    Lippuner, Jonas; Roberts, Luke F.

    2015-01-01

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y e , initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y e ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y e lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y e , but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y e , s, and τ to estimate whether or not the ejecta is lanthanide-rich

  8. Lanthanide co-ordination frameworks: Opportunities and diversity

    International Nuclear Information System (INIS)

    Hill, Robert J.; Long, De-Liang; Hubberstey, Peter; Schroeder, Martin; Champness, Neil R.

    2005-01-01

    Significant successes have been made over recent years in preparing co-ordination framework polymers that show macroscopic material properties, but in the vast majority of cases this has been achieved with d-block metal-based systems. Lanthanide co-ordination frameworks also offer attractive properties in terms of their potential applications as luminescent, non-linear optical and porous materials. However, lanthanide-based systems have been far less studied to date than their d-block counterparts. One possible reason for this is that the co-ordination spheres of lanthanide cations are more difficult to control and, in the absence of design strategies for lanthanide co-ordination frameworks, it is significantly more difficult to target materials with specific properties. However, this article highlights some of the exciting possibilities that have emerged from the earliest investigations in this field with new topological families of compounds being discovered from relatively simple framework components, including unusual eight, seven and five-connected framework systems. Our own research, as well as others, is leading to a much greater appreciation of the factors that control framework formation and the resultant observed topologies of these polymers. As this understanding develops targeting particular framework types will become more straightforward and the development of designed polyfunctional materials more accessible. Thus, it can be seen that lanthanide co-ordination frameworks have the potential to open up previously unexplored directions for materials chemistry. This article focuses on the underlying concepts for the construction of these enticing and potentially highly important materials

  9. Paramagnetic probes to study PrNi5?

    International Nuclear Information System (INIS)

    Hutchinson, W.D.; Harker, S.J.; Stewart, G.A.; Chaplin, D.H.; Kaplan, N.

    1996-01-01

    The Van-Vleck paramagnet PrNi 5 has been the focus of many studies in the past as a result of its usefulness as a nuclear cooling agent. Extensive continuous wave praseodymium NMR measurements have been carried out on this compound. However pulsed NMR and therefore precise relaxation measurements particularly at mK temperatures have proved elusive. In this work we have proposed to use radiative gamma-ray detection to indirectly measure Pr NMR in PrNi 5 via cross relaxation to suitable paramagnetic impurity probes placed at Ni lattice sites. 57 Co was chosen as the most compatible nuclear orientation isotope with an appropriate nuclear g-factor. The choice of 57 Co also allows the use of Moessbauer spectroscopy to check the site occupancy. This poster details the production of a 57 Co doped PrNi 5 single crystal specimen including the specimen preparation problems encountered, 57 Fe Moessbauer and preliminary nuclear orientation measurements

  10. Improved paramagnetic chelate for molecular imaging with MRI

    International Nuclear Information System (INIS)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-01-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

  11. Paramagnetic metal complexes as potential relaxation agents for NMR imaging

    International Nuclear Information System (INIS)

    Coroiu, Ilioara; Demco, D. E.; Darabont, Al.; Bogdan, M.

    1997-01-01

    The development of nuclear magnetic resonance (NMR) imaging technique as a clinical diagnostic modality has prompted the need for a new class of pharmaceuticals. These drugs must be administered to a patient in order to enhance the image contrast between the normal and diseased tissue and/or indicate the status of organ function or blood flow. Paramagnetic compounds are presently undergoing extensive evaluation as contrast agents in magnetic resonance imaging (MRI). These agents increase contrast in MRI by differentially localizing in tissue where they increase the relaxation rates of nearby water protons. The longitudinal R 1 and transverse R 2 relaxivities were measured as a function of molar concentrations for some new paramagnetic complexes like the following: dysprosium, erbium and gadolinium citrates, gadolinium methylene diphosphonate, dysprosium and gadolinium iminodiacetate, manganese para-aminobenzoate and copper nicotinate. The available theoretical approaches for quantitative understanding are presented. (authors)

  12. Improved paramagnetic chelate for molecular imaging with MRI

    Science.gov (United States)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  13. The paramagnetic effect in Type-I superconductors

    International Nuclear Information System (INIS)

    Rothen, F.; Lievre, C.

    1975-01-01

    The paramagnetic effect in superconductors was first observed by Steiner and Schoeneck in 1943. This effect takes place in a cylindrical wire if superconductivity is destroyed by a current J in the presence of a magnetic field He parallel to the axis: one notices that the average longitudinal magnetic induction inside the wire can greatly exceed He. An attempt is made to compute the maximal value of the longitudinal magnetic permeability of the current-carrying wire. (Auth.)

  14. Dynamic polarization in paramagnetic solids and microscopic correlation functions

    International Nuclear Information System (INIS)

    Boucher, Jean-Paul

    1972-01-01

    The different effects of Dynamic Nuclear Polarization in paramagnetic solids are described by means of a single thermodynamic formalism. In the case of large exchange interactions, the Overhauser effect correlated with nuclear relaxation time measurements can provide a way of studying correlation functions between electronic spins. This method is used to study the low-frequency behaviour of the microscopic spectral density which should diverge as ω → 0, in the case of a linear exchange chain. (author) [fr

  15. Paramagnetism and plasma beta in a screw-pinch

    International Nuclear Information System (INIS)

    Lehnert, B.; Scheffel, J.

    1991-02-01

    Anisotropic resistivity causes paramagnetic effects (B z ' (r) less then 0) in a screw pinch, being basically different to the self-relaxation described by Taylor. We compute, analytically and numerically, the resulting effect on equilibrium in a 1-D straight cylindrical plasma. In particular we compute paramagnetic effects on the plasma radius and on plasma beta. Ohm's law also contains diamagnetic terms; in this paper we consider radial particle diffusion and the Nernst effect. In a Tokamak or rector plasma these effects are shown to be negligible, whereas they may contribute in present ULQ, Extrap and RFP experiments. A basic result is an expression for the coupling between the poloidal and axial magnetic field components with the above effects included. A result of specific importance to the Extrap programme is that plasma current limitation can arise from lack of equilibrium when the plasma radius tends to exceed its upper limit, being defined by a magnetic or material limiter. The paramagnetic effect described in this work lowers the plasma beta further, making D-D reactor depending on safety factors q(a) bigger than 1 seems less attainable. (au)

  16. Electromagnetic activity of a pulsating paramagnetic neutron star

    International Nuclear Information System (INIS)

    Bastrukov, S.I.; Podgainy, D.V.; Yang, J.; Weber, F.

    2002-01-01

    The fact that neutron star matter possesses the capability of maintaining a highly intense magnetic field has been and still is among the most debatable issues in pulsar astrophysics. Over the years, there were several independent suggestions that the dominant source of pulsar magnetism is either the field-induced or the spontaneous magnetic polarization of the baryon material. The Pauli paramagnetism of degenerate neutron matter is one of the plausible and comprehensive mechanisms of the magnetic ordering of neutron magnetic moments, promoted by a seed magnetic field inherited by the neutron star from a massive progenitor and amplified by its implosive contraction due to the magnetic flux conservation. Adhering to this attitude and based on the equations of magnetoelastic dynamics underlying continuum mechanics of single-axis magnetic insulators, we investigate electrodynamics of a paramagnetic neutron star undergoing nonradial pulsations. We show that the suggested approach regains a recent finding of Akhiezer et al. that the spin-polarized neutron matter can transmit perturbations by low-frequency transverse magnetoelastic waves. We found that nonradial torsional magnetoelastic pulsations of a paramagnetic neutron star can serve as a powerful generator of a highly intense electric field producing the magnetospheric polarization charge whose acceleration along the open magnetic field lines leads to the synchrotron and curvature radiation. Analytic and numerical estimates for periods of nonradial torsional magnetoelastic modes are presented and are followed by a discussion of their possible manifestation in currently monitored activity of pulsars and magnetars

  17. Adsorption behaviors of trivalent actinides and lanthanides on pyridine resin in lithium chloride aqueous solution

    International Nuclear Information System (INIS)

    Tatsuya Suzuki

    2013-01-01

    The adsorption behaviors of trivalent actinides and lanthanides on pyridine resin in lithium chloride aqueous solution were investigated. The adsorbed amounts of lanthanides and the degree of mutual separation of lanthanides increased with an increase in the concentration of lithium chloride in aqueous solution. The group separation of the trivalent actinides and lanthanides was observed. This separation phenomenon is similar in a hydrochloric acid solution. However, the adsorption behavior of lanthanides in lithium chloride is different from their behavior in a hydrochloric acid solution. This fact shows that the adsorption mechanisms of lanthanides in a lithium chloride aqueous solution and in a hydrochloric acid solution are different; the adsorption mechanisms are attributed to the ion exchange in a hydrochloric acid solution, and to the complex formation with pyridine group in a lithium chloride solution. (author)

  18. 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)

  19. Rationalization of Anomalous Pseudocontact Shifts and Their Solvent Dependence in a Series of C3-Symmetric Lanthanide Complexes.

    Science.gov (United States)

    Vonci, Michele; Mason, Kevin; Suturina, Elizaveta A; Frawley, Andrew T; Worswick, Steven G; Kuprov, Ilya; Parker, David; McInnes, Eric J L; Chilton, Nicholas F

    2017-10-11

    Bleaney's long-standing theory of magnetic anisotropy has been employed with some success for many decades to explain paramagnetic NMR pseudocontact shifts, and has been the subject of many subsequent approximations. Here, we present a detailed experimental and theoretical investigation accounting for the anomalous solvent dependence of NMR shifts for a series of lanthanide(III) complexes, namely [LnL 1 ] (Ln = Eu, Tb, Dy, Ho, Er, Tm, and Yb; L 1 : 1,4,7-tris[(6-carboxypyridin-2-yl)methyl]-1,4,7-triazacyclononane), taking into account the effect of subtle ligand flexibility on the electronic structure. We show that the anisotropy of the room temperature magnetic susceptibility tensor, which in turn affects the sign and magnitude of the pseudocontact chemical shift, is extremely sensitive to minimal structural changes in the first coordination sphere of L 1 . We show that DFT structural optimizations do not give accurate structural models, as assessed by the experimental chemical shifts, and thus we determine a magnetostructural correlation and employ this to evaluate the accurate solution structure for each [LnL 1 ]. This approach allows us to explain the counterintuitive pseudocontact shift behavior, as well as a striking solvent dependence. These results have important consequences for the analysis and design of novel magnetic resonance shift and optical emission probes that are sensitive to the local solution environment and polarity.

  20. 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.

  1. The spectroscopy and structure of some lanthanide chlorides in amide solutions

    International Nuclear Information System (INIS)

    Legendziewicz, J.; Bukietynska, K; Jezowsky-Trzebiatowska, B.

    1974-01-01

    The absorption spectra of Pr, Nd, Ho, and Er anhydrous and hydrated chlorides in formamide, methyl-, dimethyl-, and diethylformamide solutions have been investigated in the range of 8000 - 4200 cm -1 . By the Judd-Oefelt method of intensity analysis and by calculating the nepheloauxetic effect, the first coordination sphere of lanthanide ions and the approximate symmetry of amide solvates of anhydrous and hydrated lanthanide chlorides were determined. A difference between symmetry and coordination numbers for light and heavy lanthanide solvates has been found. Some considerations regarding the structure of lanthanide solvates and structure of amide molecules have been made. (B.T.)

  2. Lanthanide Selective Sorbents: Self-Assembled Monolayers on Mesoporous Supports (SAMMS)

    Energy Technology Data Exchange (ETDEWEB)

    Fryxell, Glen E.; Wu, Hong; Lin, Yuehe; Shaw, Wendy J.; Birnbaum, Jerome C.; Linehan, John C.; Nie, Zimin; Kemner, Kenneth M.; Kelly, Shelley

    2004-11-01

    Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a “hard” anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized.

  3. Behaviour of trivalent actinides and lanthanide elements in chloride solution; Comportement des lanthanides et transuraniens trivalents en milieu chlorhydrique

    Energy Technology Data Exchange (ETDEWEB)

    Marin, B [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    The aim of this work is to compare the complexation in chloride solutions of trivalent lanthanides and actinides. We have first studied the solvatation of these cations without complexation. We found a difference between Am, Cm and Rare Earths (we can separate lanthanides into Light and Heavy Rare Earths). For studying the complexation we choose the technic of electrophoresis on paper after establishing a simple theory of mobilities in complex solutions. The hydrolysis of these cations was studied and compared in chloride solutions. We have then studied the complexation with the Cl{sup -} ligand in some solutions: HCl, NH{sub 4}Cl, CaCl{sub 2}, CeCl{sub 3}, LiCl. We have established that the complexation is the same in dilute HCl solutions but in concentrated solutions the trivalent actinides are more complexed. This difference is sharper in LiCl solutions. We also proposed the different models of complex in these solutions. (author) [French] Le but de ce travail est de comparer les transuraniens et lanthanides trivalents au point de vue de leur complexation en solution chlorhydrique. Nous avons ete amenes tout d'abord a etudier la solvatation de ces cations non complexes. C'est ainsi que nous pouvons constater une difference entre Am, Cm et les lanthanides. Ces derniers pouvant se separer en lanthanides legers et lanthanides lourds. Pour etudier la complexation nous avons utilise l'electrophorese sur papier apres avoir donne une theorie simple des mobilites en milieu complexant. Apres avoir etudie et compare l'hydrolyse de ces divers cations en solution chlorhydrique, nous avons etudie leur complexation avec l'ion Cl{sup -} dans dans divers milieux: HCl, NH{sub 4}Cl, CaCl{sub 2}, CeCl{sub 3}, LiCl. ous avons note qu'en solution HCl les deux series se comportent de la meme facon pour des concentrations faibles en Cl{sup -} mais que les transuraniens se complexent plus fortement dans les solutions concentrees. Cette difference s'accroit encore dans les milieux

  4. 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

  5. Optical Properties of Lanthanides in Condensed Phase, Theory and Applications

    Directory of Open Access Journals (Sweden)

    Renata Reisfeld

    2015-04-01

    Full Text Available The basic theories of electronic levels and transition probabilities of lanthanides are summarized. Their interpretation allows practical preparation of new materials having application in lighting, solar energy utilization, optoelectronics, biological sensors, active waveguides and highly sensitive bioassays for in vitro detection in medical applications. The ways by which the weak fluorescence arising from electronic transition within the four f-configurations can be intensified will be discussed. This includes the intermixing of the four f-states with ligands of the host matrix, excitation to higher d-electronic states. Additional intensification of luminescence by plasmonic interaction with gold, silver and copper nanoparticles will be discussed. A short history of the time development of the research and the names of the scientists who made the major contribution of our understanding of lanthanides spectroscopy are presented.

  6. Medium temperature reaction between lanthanide and actinide carbides and hydrogen

    International Nuclear Information System (INIS)

    Dean, G.; Lorenzelli, R.; Pascard, R.

    1964-01-01

    Hydrogen is fixed reversibly by the lanthanide and actinide mono carbides in the range 25 - 400 C, as for pure corresponding metals. Hydrogen goes into the carbides lattice through carbon vacancies and the total fixed amount is approximately equal to two hydrogen atoms per initial vacancy. Final products c.n thus be considered as carbo-hydrides of general formula M(C 1-x , H 2x ). The primitive CFC, NaCl type, structure remains unchanged but expands strongly in the case of actinide carbides. With lanthanide carbides, hydrogenation induces a phase transformation with reappearance of the metal structure (HCP). Hydrogen decomposition pressures of all the studied carbo-hydrides are greater than those of the corresponding di-hydrides. (authors) [fr

  7. Fluorescence Spectra Studies on the Interaction between Lanthanides and Calmodulin

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The conformation of Calmodulin(CaM) induced by lanthanides has been examined using fluorescence methods.With the addition of lanthanide (Ln3+), the intrinsic fluorescence intensity of CaM without calcium ions (Apo-CaM) first increases and then decreases.Ln3+ causes the decrease of intrinsic fluorescence intensity of calcium saturated CaM (Ca2+4-CaM) only at high concentrations.At low concentrations, Ln3+ results not only in the enhancement of fluorescence intensity of Apo-CaM, but also in a blue shift of the maximum emission wavelengh of dansyl labeled calmodulin(Apo-D-CaM).The molecular mechanism of the interaction between Ln3+ and CaM has been discussed in the light of the fluorescence spectra.

  8. 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)

  9. Stability complexes of lanthanide ions with some macrocyclic polyethers

    International Nuclear Information System (INIS)

    Poluehktov, N.S.; Malinka, E.V.; Meshkova, S.B.; Bel'tyukova, S.V.; Danilkovich, M.M.

    1984-01-01

    Stability of lanthanide complexes with macrocyclic polyethers has been studied versus the number of f-electrons, spin- and orbital angular momenta of the Lu 3+ ion ground states. The following compounds were used as macrocyclic complexones: 12-crown-4 (12C4), tert-bulylbenzo-15-crown-5(BB15C5), 18-crown-6 (18C6), ditert-butylbenzo-18-crown-6(DBB18C6), dibenzo-30-crown-10 (DB30C10), cryptand [2, 2, 1] (Cr[2, 2, 1]). It is shoWn that the stability constants of the studied lanthanide complexes can be described rather satisfactorily by an expression suggested earlier that relates their values with the number of 4f-electrons and the S and L quantum numbers of the ground states of the lantharide ions

  10. Quantum chemical prediction of antennae structures in lanthanide complexes

    International Nuclear Information System (INIS)

    Ottonelli, M.; Musso, G.F.; Rizzo, F.; Dellepiane, G.; Porzio, W.; Destri, S.

    2008-01-01

    In this paper the quantum chemical semiempirical procedure recently proposed by us to predict ground- and excited-state geometries of lanthanide complexes, the pseudo coordination centre method (PCC), is preliminarily compared with the semiempirical sparkle model for the calculation of lanthanide complexes (SMLC). Contrary to the SMLC method, where the rare-earth ion is replaced by a reparameterized sparkle atom, in our approach we replace it with a metal ion which is already present in the chosen semiempirical parameterization. This implies that in the optimization of the geometry of the complexes a different weight is implicitly given to the complex region including the rare-earth ion and its neighbour atoms with respect to the region of the ligands aggregate. As a consequence our approach is expected to reproduce better than the SMLC one the geometry of the ligands aggregate embedded in the complex, while the contrary happens for the coordination distances

  11. Synthesis and investigation of uranylphosphates, uranylarsenanes, and uranylvanadates of lanthanides

    International Nuclear Information System (INIS)

    Chernorukov, N.G.; Knyazev, A.V.; Barch, S.V.; Feoktisova, S.V.; Suleymanov, E.V.

    2000-01-01

    Currently compounds A k (B V UO 6 ) k-m (OH) m .nH 2 O (A k - Y, La-Lu, B V -P, As, V) are of interest as the possible mineral-like forms of linkage in an environment of uranium and radioactive isotopes of lanthanides of an artificial origin, as modeling systems for study of similar compounds of six-valence neptunium and plutonium, and as objects, suitable for allocation and division lanthanides and actinides. In order to determine a role of water molecules in the formation of the crystal structure of inorganic hydrates and processes of dehydration uranium minerals with the general formula A k (B V UO 6 ) k-m (OH) m .nH 2 O and their synthetic analogues (A k - one-, two- and three-valent elements, B V -elements of the fifth group of Periodic system) are rather convenient objects. (authors)

  12. Organometallic compounds of the lanthanides, actinides and early transition metals

    Energy Technology Data Exchange (ETDEWEB)

    Cardin, D J [Trinity Coll., Dublin (Ireland); Cotton, S A [Stanground School, Peterborough (UK); Green, M [Bristol Univ. (UK); Labinger, J A [Atlantic Richfield Co., Los Angeles, CA (USA); eds.

    1985-01-01

    This book provides a reference compilation of physical and biographical data on over 1500 of the most important and useful organometallic compounds of the lanthanides, actinides and early transition metals representing 38 different elements. The compounds are listed in molecular formula order in a series of entries in dictionary format. Details of structure, physical and chemical properties, reactions and key references are clearly set out. All the data is fully indexed and a structural index is provided.

  13. 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)

  14. Magnetic dipole moments of odd-odd lanthanides

    International Nuclear Information System (INIS)

    Sharma, S.D.; Gandhi, R.

    1988-01-01

    Magnetic dipole moments of odd-odd lanthanides. Collective model of odd-odd nuclei is applied to predict the magnetic dipole moments, (μ) of odd-odd lanthanides. A simplified version of expression for μ based on diagonalisation of Hamiltonian (subsequent use of eigenvectors to compute μ) is developed for cases of ground state as well as excited states using no configuration mixing and is applied to the cases of odd-odd lanthanides. The formulae applied to the eleven (11) cases of ground states show significant improvement over the results obtained using shell model. Configuration mixing and coriolis coupling is expected to cause further improvement in the results. On comparing the earlier work in this direction the present analysis has clarified that in the expression μ the projection factors have different signs for the case I=Ωp - Ωn and I=Ωn - Ωp, and sign of μ is negative in general in the second case while it is positive in all others of spin projection alignments. Although the general expression holds for excited states as well but in lanthanide region, the experimental reports of magnetic dipole moments of excite states (band heads of higher rational sequences) are not available except in case of five (5) neutron resonance states which cannot be handled on the basis of the present approach with no configuration mixing. Although in the present discussion, the model could not be applied to excited states but the systematics of change in its magnitude with increasing spin at higher rational states is very well understood. The particle part supressed under faster rotation of the nuclear core and thus finally at higher spin I, the value μ is given by μ=g c I (same as in case of even-even nuclei). These systematics are to be verified whenever enough data for higher excited states are available. (author). 11 refs

  15. Lanthanides separation by counter - current electrophoretic using α - hydroxyisobutyric acid

    International Nuclear Information System (INIS)

    Alleluia, I.B.

    1975-01-01

    Studies about counter-current electrophoretic separation of rare earth metal ions using α-hydroxyisobutyric acid as complexing electrolyte are discussed. La, Pr, Nd, Sm and Eu were separated and fractions with purities better than 99,9% were obtained, using neutron activation analysis. A relation between the first stability constant of the α-hydroxyisobutyrate/lanthanide complexes and their migration velocities were observed. (M.J.C.) [pt

  16. Analytical applications of superacid dissolution of actinide and lanthanide substrates

    International Nuclear Information System (INIS)

    Avens, L.R.; Eller, P.G.; Asprey, L.B.; Abney, K.D.; Kinkead, S.A.

    1987-01-01

    The superacid system HF/SbF 5 is extraordinarily effective for total dissolution of actinide and lanthanide ceramic oxides, fluorides, and metals. Optical or gamma spectroscopy can be used directly on the solutions. Evaporation of the HF/SbF 5 solvent under vacuum leaves a residue which is easily dissolved by ordinary mineral acids. The resulting aqueous solutions are readily amenable to conventional analytical methods

  17. Lanthanide and actinide separation studies using liquid chromatography

    International Nuclear Information System (INIS)

    Datta, Arpita; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2011-01-01

    Gradient elution procedure for isolation of individual lanthanides was studied extensively at our laboratory using monolith support. A large number of gradients were developed by varying the concentrations of CSA, α-HIBA, mobile phase pH and mobile phase flow rate. In a typical gradient run, the concentration of CSA and mobile phase flow rate were kept constant and only α-HIBA concentration was varied. Based on these studies, a binary gradient elution method was developed for the rapid separation of lanthanides, from La to Lu in about 2.8 min, with a mobile phase CSA, α-HIBA and pH being 0.03M, 0.05 to 0.15M and 3.4-3.8 respectively. The direct injection of dissolver solution from FBTR spent fuel into HPLC was investigated and the results are shown. The lanthanides present in dissolver solution were mutually separated as well as resolved from uranium and plutonium under dynamic ion exchange conditions using the monolithic column. The concentration of La, Ce, Pr, Nd and Sm were determined in the dissolver solution using a calibration plot

  18. 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.

  19. 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)

  20. Thermodecomposition of lanthanides (III) and ytrium (III) glucoheptonates

    International Nuclear Information System (INIS)

    Giolito, J.

    1987-01-01

    The lanthanides (III) and yttrium (III) glucoheptonates as well the D-glucoheptono 1-4 lactone were studied using common analytical methods, elemental microanalysis of carbon and hydrogen, thermogravimetry and differential scanning calorimetry. These compounds were prepared from the reaction between the lanthanides (III) and yttrium (III) hydroxides and glucoheptonic acid aqueous solution obtained by means of the delta lactone hydrolysis of this acid. After stoichiometric reaction the compounds were precipitated by the addition of absolute ethanol, washed with the same solvent and dried in desiccator. Thermogravimetric the (TG) curves of the lanthanides glucoheptonates of the ceric group present thermal profiles with enough differences permitting an easy caracterization of each compound and the yttrium (III) glucoheptonate TG curve showed a great similarity with the erbium (III) compound TG curve. The differential scanning calometry (DSC) curves showed endothermic and exothermic peaks by their shape, height and position (temperature) permit an easy and rapid identification of each compound specially if DSC and TG curves were examined simultaneously. (author) [pt

  1. Citrate based ''TALSPEAK'' lanthanide-actinide separation process

    International Nuclear Information System (INIS)

    Del Cul, G.D.; Bond, W.D.; Toth, L.M.; Davis, G.D.; Dai, S.; Metcalf, D.H.

    1994-09-01

    The potential hazard posed to future generations by long-lived radionuclides such as the transuranic elements (TRU) is perceived as a major problem associated with the use of nuclear power. TRU wastes have to remain isolated from the environment for ''geological'' periods of time. The costs of building, maintaining, and operating a ''geological TRU repository'' can be very high. Therefore, there are significant economical advantages in segregating the relatively low volume of TRU wastes from other nuclear wastes. The chemical behavior of lanthanides and actinides, 4f and 5f elements respectively, is rather similar. As a consequence, the separation of these two groups is difficult. The ''TALSPEAK'' process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. The method is based on the preferential complexation of the trivalent actinides by an aminopolyacetic acid. Cold experiments showed that by using citric acid the deleterious effects produced by impurities such as zirconium are greatly reduced

  2. Biosorption of lanthanides using three kinds of seaweed biomasses

    International Nuclear Information System (INIS)

    Sakamoto, Nobuo; Wang, Yudan; Gao, Lidi; Kano, Naoki; Imaizumi, Hiroshi

    2010-01-01

    In order to evaluate the efficiency of seaweed biomass as sorbent for rare earth elements (REEs), sorption experiment from aqueous solutions containing known amount of lanthanide (La, Eu or Yb) using three kinds of Ca-loaded dried seaweeds (brown algae: Sargassum hemiphyllum, green algae: Ulva pertusa and red algae: Schizymenia dubyi) in single component system was explored. Furthermore, the sorption mechanism of these elements was investigated by applying Langmuir and Freundlich isotherm equations to the data obtained. In addition, to confirm the characteristics of the seaweed biomasses, the surface morphology of the biomass before and after metal adsorption was determined by Scanning Electron Microscope (SEM). Consequently, the following matters have been mainly clarified. (1) The morphology of Sargassum hemiphyllum and Ulva pertusa surface has hardly changed even after exposing to metals. On the other hand, the change of the surface condition on Schizymenia dubyi after adsorption was observed. (2) Adsorption isotherms using the seaweed biomass can be described by Langmuir and Freundlich isotherms satisfactorily for lanthanide. These adsorption may have occurred mainly by monolayer reaction because of better-fitting for Langmuir model. (3) The seaweed biomasses could be an efficient sorbent for REEs. Particularly, Ulva pertusa is found to be a promising biosorbent for removing La. (4) Ion-exchange process is considered to be the main mechanism responsible for the sorption of lanthanide ion onto the seaweed biomass. (author)

  3. 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.

  4. 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.

  5. Lanthanide tris(β-diketonates) as useful probes for chirality determination of biological amino alcohols in vibrational circular dichroism: ligand to ligand chirality transfer in lanthanide coordination sphere.

    Science.gov (United States)

    Miyake, Hiroyuki; Terada, Keiko; Tsukube, Hiroshi

    2014-06-01

    A series of lanthanide tris(β-diketonates) functioned as useful chirality probes in the vibrational circular dichroism (VCD) characterization of biological amino alcohols. Various chiral amino alcohols induced intense VCD signals upon ternary complexation with racemic lanthanide tris(β-diketonates). The VCD signals observed around 1500 cm(-1) (β-diketonate IR absorption region) correlated well with the stereochemistry and enantiomeric purity of the targeted amino alcohol, while the corresponding monoalcohol, monoamine, and diol substrates induced very weak VCD signals. The high-coordination number and dynamic property of the lanthanide complex offer an effective chirality VCD probing of biological substrates. © 2014 Wiley Periodicals, Inc.

  6. Neutron studies of paramagnetic fullerenols’ assembly in aqueous solutions

    Science.gov (United States)

    Lebedev, V. T.; Szhogina, A. A.; Suyasova, M. V.

    2018-03-01

    Recent results on structural studies of aqueous solutions of water-soluble derivatives of endofullerenes encapsulating 4f- and 3d-elements have been presented. Neutron small angle scattering experiments allowed recognize subtle features of fullerenols assembly as dependent on chemical nature (atomic number) of interior atom, pH-factor and temperature of solutions. It was observed a fractal-type fullerenols’ ordering at the scale of correlation radii ∼ 10-20 nm when molecules with iron atoms are integrated into branched structures at low concentrations (C ≤ 1 % wt.) and organized into globular aggregates at higher amounts (C > 1 % wt.). On the other hand, for Lanthanides captured in carbon cages the supramolecular structures are mostly globular and have larger gyration radii ∼ 30 nm. They demonstrated a good stability in acidic (pH ∼ 3) and neutral (pH ∼ 7) media that is important for forthcoming medical applications.

  7. The Paramagnetism of Dissolved Mn in {alpha} and {beta} Brasses

    Energy Technology Data Exchange (ETDEWEB)

    Myers, H P; Westin, R

    1962-12-15

    Paramagnetic susceptibility measurements have been made on {alpha} and {beta} brasses containing {approx} 1 w/o Mn. The susceptibility varied with temperature according to the Curie Weiss law and the Curie constant and thereby the Bohr magneton number per Mn atom were determined. Interpreted in terms of valency, Mn monovalent in copper has a valency in {alpha} brass which decreases progressively with zinc content attaining the value 0.58 at the limiting of composition. Mn in {beta} brass exhibits a valency 0.8. These results are not in keeping with previous values for the valency of manganese as determined from phase boundary relationships and electron to atom ratios.

  8. Moessbauer effect and electron paramagnetic resonance studies on yeast aconitase

    International Nuclear Information System (INIS)

    Suzuki, Takashi; Maeda, Yutaka; Sakai, Hiroshi; Fujimoto, Shigeru; Morita, Yuhei.

    1975-01-01

    The Moessbauer effect and electron paramagnetic resonance (EPR) of yeast aconitase [EC 4.2.1.3] purified from the cells of Candida lipolytica (ATCC 20114) were measured. Moessbauer spectra suggested that yeast acontitase mostly contained two high-spin Fe(III) ions in an antiferromagnetically coupled binuclear complex that resembled oxidized 2 Fe ferredoxins, together with a small amount of high-spin Fe(II). EPR spectra recorded no signal at 77 0 K, but showed a slightly asymmetric signal centered at g=2.0 at 4.2 0 K, presumably due to the small amount of Fe(II) Fe(III) pairs. (auth.)

  9. Multi-photon Rabi oscillations in high spin paramagnetic impurity

    International Nuclear Information System (INIS)

    Bertaina, S; Groll, N; Chen, L; Chiorescu, I

    2011-01-01

    We report on multiple photon monochromatic quantum oscillations (Rabi oscillations) observed by pulsed EPR (Electron Paramagnetic Resonance) of Mn 2+ (S = 5/2) impurities in MgO. We find that when the microwave magnetic field is similar or large than the anisotropy splitting, the Rabi oscillations have a spectrum made of many frequencies not predicted by the S = l/2 Rabi model. We show that these new frequencies come from multiple photon coherent manipulation of the multi-level spin impurity. We develop a model based on the crystal field theory and the rotating frame approximation, describing the observed phenomenon with a very good agreement.

  10. Moessbauer studies on the paramagnetic porton of alkidirat meteorite

    International Nuclear Information System (INIS)

    Kamal, Huda Mohamed

    1995-11-01

    This work was performed on a sample from alkidirat meteorite which fell west of Sudan by means of Moessbauer effect spectrometer. results showed the absence of transition temperature from the paramagnetic state to the magnetic state in the temperature range from 300K down to 16K. Also, it was found that olivine and ortho pyroxene exist together in site M 1 , while clinothyroxene exists alone in site M 2 . Formula for the composition of ortho pyroxene in the sample were also obtained and they were in good agreement with previous studies. The disorder parameter was also calculated and it showed that the pyroxene present in the sample is well-ordered.(Author)

  11. Optical and paramagnetic properties of Ti in LiF

    International Nuclear Information System (INIS)

    Krystek, M.

    1982-01-01

    Titanium replaces substitutionally Li + at its lattice site in LiF. The resulting deep impurity must be understood as TiF 6 -cluster. The symmetry of this cluster is octahedral in the case of the unoccupied impurity. If the impurity will be occupied by an electron, a trigonal distortion of the cluster results, whereby the orbital degeneracy of the ground state will be liftet. Since the occupied impurity is paramagnetic, the symmetry reduction could be proved by ENDOR measurements. Using a calculated term diagram of the impurity inside the crystal a model is offered to explain the photoluminescence and the thermoluminescence of LiF:Ti. (orig./HP) [de

  12. Development of polarization magneto-optics of paramagnetic crystals

    International Nuclear Information System (INIS)

    Zapasskij, V.S.; Feofilov, P.P.

    1975-01-01

    The present status of the polarization magnetooptics of crystals containing paramagnetic ion impurities is reviewed. The paper discusses methods of measurement of circular magnetic anisotropy and results obtained in recent years in the field of conventional magnetooptical studies, e.g., magnetooptical activity in absorption spectra for intrinsic and impurity defects in crystals, luminescence magnetic circular polarization, anisotropy of magnetooptical activity in cubic crystals. The main emphasis is placed on new trends in polarization magnetooptics: studies of interactions of a spin system with a lattice, in particular, spin-lattice relaxation and spin memory effect, experiments in the double radiooptical resonance, studies of optical spin relaxation, nonlinear magnetooptical effects, etc

  13. Magnon Spin Hall Magnetoresistance of a Gapped Quantum Paramagnet

    Science.gov (United States)

    Ulloa, Camilo; Duine, R. A.

    2018-04-01

    Motivated by recent experimental work, we consider spin transport between a normal metal and a gapped quantum paramagnet. We model the latter as the magnonic Mott-insulating phase of an easy-plane ferromagnetic insulator. We evaluate the spin current mediated by the interface exchange coupling between the ferromagnet and the adjacent normal metal. For the strongly interacting magnons that we consider, this spin current gives rise to a spin Hall magnetoresistance that strongly depends on the magnitude of the magnetic field, rather than its direction. This Letter may motivate electrical detection of the phases of quantum magnets and the incorporation of such materials into spintronic devices.

  14. Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

    Science.gov (United States)

    Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

    1987-01-01

    A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

  15. Retrospective dosimetry of nail by Electron Paramagnetic Resonance

    International Nuclear Information System (INIS)

    Giannoni, Ricardo A.; Rodrigues Junior, Orlando

    2015-01-01

    The purpose of this study is to characterize samples of human nails, subjected to irradiation of high doses through Technical Electron Paramagnetic Resonance (EPR). The goal is to establish a dose/response relationship in order to assess dose levels absorbed by individuals exposed in radiation accidents situations, retrospectively. Samples of human nails were irradiated with gamma radiation, and received a dose of 20 Gy. EPR measurements performed on samples before irradiation identified EPR signals associated with defects caused by the mechanical action of the sample collection. After irradiation other species of free radicals, associated with the action of gamma radiation, have been identified

  16. Contribution to the study of electron paramagnetic resonance and relaxation

    International Nuclear Information System (INIS)

    Theobald, Jean-Gerard

    1962-01-01

    This research thesis reports an experimental work which comprises the development of a very practical and very sensitive electron paramagnetic resonance spectrometer, and the use of this equipment for the study of irradiated substances and carbons. By studying electronic resonance signals by fast modulation of the magnetic field, the author studied phenomena of quick passage in electronic resonance, and showed that the study of these phenomena requires observation systems with a particularly large bandwidth. He reports the measurement of the line width of packs of spins of inhomogeneous lines by two different methods [fr

  17. Size-dependent concentration of N0 paramagnetic centres in HPHT nanodiamonds

    OpenAIRE

    Yavkin, Boris V; Mamin, Georgy V; Gafurov, Marat R.; Orlinskii, Sergei B.

    2015-01-01

    Size-calibrated commercial nanodiamonds synthesized by high-pressure high-temperature (HPHT) technique were studied by high-frequency W and conventional X band electron paramagnetic resonance (EPR) spectroscopy. The numbers of spins in the studied samples were estimated. The core-shell model of the HPHT nanodiamonds was proposed to explain the observed dependence of the concentration of the N0 paramagnetic centers. Two other observed paramagnetic centers are attributed to the two types of str...

  18. Energy transfer and quenching processes of excited uranyl ion and lanthanide ions in solutions

    International Nuclear Information System (INIS)

    Yamamura, Tomoo; Tomiyasu, Hiroshi

    1995-01-01

    Deactivation processes of photoexcited uranyl ion by various lanthanide ions in aqueous solution were studied. Each lanthanide ions show different interaction with excited uranyl ion depending on its lowest excited energy level, the number of 4f electrons and the acid concentration of the solution. (author)

  19. Adducts compounds of lanthanides (III) trifluoreacetates and yttrium and the N,N - dimenthylformamide

    International Nuclear Information System (INIS)

    Silva, M. das G. da.

    1983-01-01

    Some studies on lanthanides, f transition elements, and yttrium are presented. Adducts of lanthanides trifluoroacetates and N,N -dimethylformamide are described. The characterization of complexes from elementar analysis, conductance measurements, X-ray patterns, vibrational, electronics and fluorescence spectra are analysed. (M.J.C.) [pt

  20. Specification and comparative calculation of enthalpies and Gibbs formation energies of anhydrous lanthanide nitrates

    International Nuclear Information System (INIS)

    Del' Pino, Kh.; Chukurov, P.M.; Drakin, S.I.

    1980-01-01

    Analyzed are the results of experimental depermination of formation enthalpies of waterless nitrates of lanthane cerium, praseodymium, neodymium and samarium. Using method of comparative calculation computed are enthalpies of formation of waterless lanthanide and yttrium nitrates. Calculated values of enthalpies and Gibbs energies of waterless lanthanide nitrate formation are tabulated

  1. Spectrally resolved confocal microscopy using lanthanide centred near-IR emission

    DEFF Research Database (Denmark)

    Liao, Zhiyu; Tropiano, Manuel; Mantulnikovs, Konstantins

    2015-01-01

    The narrow, near infrared (NIR) emission from lanthanide ions has attracted great interest, particularly with regard to developing tools for bioimaging, where the long lifetimes of lanthanide excited states can be exploited to address problems arising from autofluorescence and sample transparency...

  2. Coordination symmetry determination of some lanthanide complexes by x-ray diffraction

    International Nuclear Information System (INIS)

    Oliveira Paiva Santos, C. de.

    1983-01-01

    The x-ray determination of the crystal and molecular structures of three lanthanide complexes is described. The work is a contribution to the study of the coordination chemistry of lanthanide ions with organic ligands and in particular, it aims to compare the observed point symmetry of the ion environment with spectroscopic predictions. (author)

  3. Tuning the sensitivity of lanthanide-activated NIR nanothermometers in the biological windows

    NARCIS (Netherlands)

    Cortelletti, P.; Skripka, A.; Facciotti, C.; Pedroni, M.; Caputo, G.; Pinna, N.; Quintanilla, M.; Benayas, A.; Vetrone, F.; Speghini, A.

    2018-01-01

    Lanthanide-activated SrF2 nanoparticles with a multishell architecture were investigated as optical thermometers in the biological windows. A ratiometric approach based on the relative changes in the intensities of different lanthanide (Nd3+ and Yb3+) NIR emissions was applied to investigate the

  4. Process for recovering yttrium and lanthanides from wet-process phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, J.A.; Weterings, C.A.

    1983-06-28

    Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

  5. Recovery of uranium and lanthanides during the production of nitrophosphate fertilizers using tertiary amyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Habashi, F; Awadalla, F T

    1986-01-01

    When phosphate rock is dissolved in nitric acid, phosphoric acid and uranium can be selectively extracted by tertiary amyl alcohol; other impurities including the lanthanides remain in the aqueous phase. Uranium can be recovered from the alcohol phase by selective stripping and the lanthanides from the raffinate by extraction with tributyl phosphate.

  6. Preparation, characterization and thermal behaviour study of double selenates of lanthanides, yttrium and beryllium

    International Nuclear Information System (INIS)

    Ribeiro, C.A.

    1988-01-01

    The lanthanides (III) and yttrium (III) double selenates were studied using common analytical methods, atomic absorption, X-ray diffraction infra-red absorption, thermogravimetry and differential thermal analysis. These compounds were prepared from the mixture of lanthanides (III) and yttrium (III) selenates aqueous solution and basic beryllium selenates aqueous solution, obeying equimolar relation (1:1) to the cation

  7. Fermionic spin liquid analysis of the paramagnetic state in volborthite

    Science.gov (United States)

    Chern, Li Ern; Schaffer, Robert; Sorn, Sopheak; Kim, Yong Baek

    2017-10-01

    Recently, thermal Hall effect has been observed in the paramagnetic state of volborthite, which consists of distorted kagome layers with S =1 /2 local moments. Despite the appearance of magnetic order below 1 K , the response to external magnetic field and unusual properties of the paramagnetic state above 1 K suggest possible realization of exotic quantum phases. Motivated by these discoveries, we investigate possible spin liquid phases with fermionic spinon excitations in a nonsymmorphic version of the kagome lattice, which belongs to the two-dimensional crystallographic group p 2 g g . This nonsymmorphic structure is consistent with the spin model obtained in the density functional theory calculation. Using projective symmetry group analysis and fermionic parton mean field theory, we identify twelve distinct Z2 spin liquid states, four of which are found to have correspondence in the eight Schwinger boson spin liquid states we classified earlier. We focus on the four fermionic states with bosonic counterpart and find that the spectrum of their corresponding root U (1 ) states features spinon Fermi surface. The existence of spinon Fermi surface in candidate spin liquid states may offer a possible explanation of the finite thermal Hall conductivity observed in volborthite.

  8. Electron paramagnetic resonance in Cu-doped ZnO

    Science.gov (United States)

    Buchheit, R.; Acosta-Humánez, F.; Almanza, O.

    2016-04-01

    In this work, ZnO and Cu-doped ZnO nanoparticles (Zn1-xCuxO, x = 3%), with a calcination temperature of 500∘C were synthesized using the sol-gel method. The particles were analyzed using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) at X-band, measurement in a temperature range from 90 K to room temperature. AAS confirmed a good correspondence between the experimental doping concentration and the theoretical value. XRD reveals the presence of ZnO phase in hexagonal wurtzite structure and a nanoparticle size for the samples synthesized. EPR spectroscopy shows the presence of point defects in both samples with g-values of g = 1.959 for shallow donors and g = 2.004 for ionized vacancies. It is important when these materials are required have been used as catalysts, as suggested that it is not necessary prepare them at higher temperature. A simulation of the Cu EPR signal using an anisotropic spin Hamiltonian was performed and showed good coincidence with the experimental spectra. It was shown that Cu2+ ions enter interstitial octahedral sites of orthorhombic symmetry in the wurtzite crystal structure. Temperature dependence of the EPR linewidth and signal intensity shows a paramagnetic behavior of the sample in the measurement range. A Néel temperature TN = 78 ± 19 K was determined.

  9. Paramagnetic ionic liquids for measurements of density using magnetic levitation.

    Science.gov (United States)

    Bwambok, David K; Thuo, Martin M; Atkinson, Manza B J; Mirica, Katherine A; Shapiro, Nathan D; Whitesides, George M

    2013-09-03

    Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev.

  10. Data acquisition system for electronic paramagnetic resonance spectrophotometer

    International Nuclear Information System (INIS)

    Pena Eguiluz, R.

    1992-01-01

    In the Atomic and Molecular Physics Laboratory at the Physics Department of the Instituto Nacional de Investigaciones Nucleares (ININ), there is in operation an electronic paramagnetic resonance spectrometer (EPR). This equipment is utilized for determine, the distribution of the absorbed energy intensity for a sample of paramagnetic substance by means of the study and analysis of its emission lines spectrum. The useful information is provided as a graphic result showing the spectrum corresponding to the analyzed sample. In similar devices like this, the researchers problem, trying to get the important information, is a hard and imprecise work, thus, this process of find the ordinate magnitudes of a approximately two hundred points, equal spaced in the spectrum, is carried out completely by hand. After this, the information is captured and processed in a personal computer. As a solution for this problem, an interface in both aspects, hardware and software adaptable to a personal computer, was designed and constructed. This interface is able to: a) To get and digitized the analogical signal, that represents the corresponding spectrum curve. b) It stores the digitized information in files and c) It displays in graphic mode the stored data, and then these are normalized in order to be transferred to a statistics and analytical software packets (Author)

  11. Effect of indium addition in U-Zr metallic fuel on lanthanide migration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Wiencek, T.; O' Hare, E.; Fortner, J.; Wright, A. [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL 60439 (United States); Cheon, J.S.; Lee, B.O. [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2017-02-15

    Advanced fast reactor concepts to achieve ultra-high burnup (∼50%) require prevention of fuel-cladding chemical interaction (FCCI). Fission product lanthanide accumulation at high burnup is substantial and significantly contributes to FCCI upon migration to the cladding interface. Diffusion barriers are typically used to prevent interaction of the lanthanides with the cladding. A more active method has been proposed which immobilizes the lanthanides through formation of stable compounds with an additive. Theoretical analysis showed that indium, thallium, and antimony are good candidates. Indium was the strongest candidate because of its low reactivity with iron-based cladding alloys. Characterization of the as-fabricated alloys was performed to determine the effectiveness of the indium addition in forming compounds with lanthanides, represented by cerium. Tests to examine how effectively the dopant prevents lanthanide migration under a thermal gradient were also performed. The results showed that indium effectively prevented cerium migration.

  12. Effect of indium addition in U-Zr metallic fuel on lanthanide migration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Soo; Wiencek, T.; O' Hare, E.; Fortner, J.; Wright, A.; Cheon, J. S.; Lee, B. O.

    2017-02-01

    Advanced fast reactor concepts to achieve ultra-high burnup (~50%) require prevention of fuel-cladding chemical interaction (FCCI). Fission product lanthanide accumulation at high burnup is substantial and significantly contributes to FCCI upon migration to the cladding interface. Diffusion barriers are typically used to prevent interaction of the lanthanides with the cladding. A more active method has been proposed which immobilizes the lanthanides through formation of stable compounds with an additive. Theoretical analysis showed that indium, thallium, and antimony are good candidates. Indium was the strongest candidate because of its low reactivity with iron-based cladding alloys. Characterization of the as-fabricated alloys was performed to determine the effectiveness of the indium addition in forming compounds with lanthanides, represented by cerium. Tests to examine how effectively the dopant prevents lanthanide migration under a thermal gradient were also performed. The results showed that indium effectively prevented cerium migration.

  13. Separation of Am from lanthanides by a synergistic mixture of purified Cyanex 301 and TBP

    International Nuclear Information System (INIS)

    Xinghai Wang; Yongjun Zhu; Rongzhou Jiao

    2002-01-01

    The dependence of the distribution ratios of 241 Am and lanthanides between purified Cyanex 301 (HBTMPDTP)-TBP-kerosene/nitrate solution on pH, lanthanide concentration in aqueous phase and degree of saponification of HBTMPDTP was investigated. The distribution ratios of 241 Am and lanthanides increase with pH and degree of saponification of HBTMPDTP and decrease with lanthanides concentration. Countercurrent multistage extraction consisting of 7 extraction, 3 washing and 2 stripping stages showed that more than 99,99% of 241 Am and less than 0.04% of lanthanides were extracted. The pH 1/2 value of Am was 2.45 compared to 3.16 in case of HBTMPDTP-kerosene extraction. (author)

  14. 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.

  15. Increasing lanthanide luminescence by use of the RETEL effect.

    Science.gov (United States)

    Leif, Robert C; Vallarino, Lidia M; Becker, Margie C; Yang, Sean

    2006-08-01

    Luminescent lanthanide complexes produce emissions with the narrowest-known width at half maximum; however, their significant use in cytometry required an increase in luminescence intensity. The companion review, Leif et al., Cytometry 2006;69A:767-778, described a new technique for the enhancement of lanthanide luminescence, the Resonance Energy Transfer Enhanced Luminescence (RETEL) effect, which increases luminescence and is compatible with standard slide microscopy. The luminescence of the europium ion macrocyclic complex, EuMac, was increased by employing the RETEL effect. After adding the nonluminescent gadolinium ion complex of the thenoyltrifluoroacetonate (TTFA) ligand or the sodium salt of TTFA in ethanol solution, the EuMac-labeled sample was allowed to dry. Both a conventional arc lamp and a time-gated UV LED served as light sources for microscopic imaging. The emission intensity was measured with a CCD camera. Multiple time-gated images were summed with special software to permit analysis and effective presentation of the final image. With the RETEL effect, the luminescence of the EuMac-streptavidin conjugate increased at least six-fold upon drying. Nuclei of apoptotic cells were stained with DAPI and tailed with 5BrdUrd to which a EuMac-anti-5BrdU conjugate was subsequently attached. Time-gated images showed the long-lived EuMac luminescence but did not show the short-lived DAPI fluorescence. Imaging of DNA-synthesizing cells with an arc lamp showed that both S phase and apoptotic cells were labeled, and that their labeling patterns were different. The images of the luminescent EuMac and fluorescent DAPI were combined to produce a color image on a white background. This combination of simple chemistry, instrumentation, and presentation should make possible the inexpensive use of the lanthanide macrocycles, Quantum Dyes, as molecular diagnostics for cytological and histopathological microscopic imaging. (c) 2006 International Society for Analytical

  16. 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.

  17. Recent progress in actinide and lanthanide solvent extraction

    International Nuclear Information System (INIS)

    Musikas, C.; Hubert, H.; Benjelloun, N.; Vitorge, P.; Bonnin, M.; Forchioni, A.; Chachaty, C.

    1983-04-01

    Work in progress on actinide solvent extraction is briefly reviewed in this paper. 1 H and 31 P NMR are used to elucidate several fundamental unsolved problems concerning organophosphorous extractants often used in actinides extraction: determination of site of dialkylthiophosphate protonation and addition of basic phosphine oxide to dibutylthiophosphoric acid dimer. Extraction of Am III and Eu from high radioactivity level wastes by tetrasubsituted methylene diamides is investigated. Trivalent actinide-lanthanide group are separated by solvent extraction using soft donor ligand complexes which are more stable. The synergism of dinonylnaphtalene sulfonic acid (HDNNS) associated with several neutral donors like TBP, TOPO, amides are examined in the trivalent and tetravalent actinide extraction

  18. Introduction to molecular magnetism from transition metals to lanthanides

    CERN Document Server

    Benelli, Cristiano

    2015-01-01

    This first introduction to the rapidly growing field of molecular magnetism is written with Masters and PhD students in mind, while postdocs and other newcomers will also find it an extremely useful guide. Adopting a clear didactic approach, the authors cover the fundamental concepts, providing many examples and give an overview of the most important techniques and key applications. Although the focus is one lanthanide ions, thus reflecting the current research in the field, the principles and the methods equally apply to other systems. The result is an excellent textbook from both a scientif

  19. Reaction between phenyl derivatives of lanthanides and carbonyl compounds

    International Nuclear Information System (INIS)

    Sigalov, A.B.; Petrov, Eh.S.; Rybakova, L.F.; Beletskaya, I.P.

    1983-01-01

    Reactions of PhLnI (Ln=Yb, Eu, Sm, Ce) with α, β-unsaturated ketons (trans-chalcone and benzalacetone) are considered as well as with 9-fluorene and benzophenone. The regioselectivity of the reaction of PhLnI addition to enones is compared with similar reactions of PhMgX and PhLi. The reaction between PhLnI and trans-chalcone proceeds regiospecifically as 1, 2-addition in contrast with reactions of PhMgI and PhLi. A new reaction of lanthanide carbinolate deoxygenation under the effect of reducers was found. The reaction product yields are presented

  20. Method of cerium separation from other lanthanides and yttrium

    International Nuclear Information System (INIS)

    Tran, Duc Hiep; Mostecky, J.

    1988-01-01

    Cerium is separated from a suspension produced during the aerial oxidation process. The suspension is subject to a cyclic process of two-stage fractional dissolution. Following the first dissolution, almost all cerium remains undissolved while 95% of the other lanthanides pass into the solution. The filtrate of the second stage of dissolution containing about 5% of ceriumm is returned for oxidation with the next batch of hydroxide mixed concentrate. Following oxidation, the two-stage fractional dissolution is repeated. This cycling provides quantitative cerium separation from other rare earth elements. (E.S.)

  1. Synthesis, characterization and reactivity of some lanthanide organometallics

    International Nuclear Information System (INIS)

    Marchal, N.

    1991-12-01

    Organo lanthanides with reactive metal-carbon bonds are obtained by direct synthesis of the metal (powder) and a hydrocarbon in ether medium, like with alkali metals. Two types of synthesis are envisaged: formation of covalent bonds by opening cycles, only biphenylene is reactive enough in regard to ytterbium and samarium, these organometallic compounds can also be prepared by the classical way, i.e. reaction of 2.2'-dilithio biphenyl on rare earth halogenides and coupling of 6.6-dimethylfulvene leading to dicyclopentadienyl compounds with Sm and Yb. The reactivity of these complexes is studied by catalysis of ethylene polymerization

  2. New strategies for the chemical separation of actinides and lanthanides

    International Nuclear Information System (INIS)

    Hudson, M.J.; Iveson, P.B.

    2002-01-01

    A general model is proposed for the effective design of ligands for partitioning. There is no doubt that the correct design of a molecule is required for the effective separation by separation of metal ions such as lanthanides(III) and actinides(III). Heterocyclic ligands with aromatic rings systems have a rich chemistry, which is only now becoming sufficiently well understood, in relation to the partitioning process. The synthesis, characterisation and structures of some chosen molecules will be introduced in order to illustrate some important features. For example, the molecule N-butyl-2-amino-4,6-di (2-pyridyl)-1,3,5-triazine (BADPTZ), which is an effective solvent extraction reagent for actinides and lanthanides, has been synthesised, characterised and its interaction with metal ions studied. The interesting and important features of this molecule will be compared with those of other heterocyclic molecules such as 2,6-bis(5-butyl-1,2,4-triazol-3-yl) pyridine (DBTZP), which is a candidate molecule for the commercial separation of actinides and lanthanide elements. Primary Coordination Sphere. One of the most critical features concerning whether a molecule is a suitable extraction reagent is the nature of the binding and co-ordination in the primary co-ordination sphere. This effect will be considered in depth for the selected heterocylic molecules. It will be shown how the bonding of the heterocyclic and nitrate ligands changes as the complete lanthanide series is traversed from lanthanum to lutetium. For effective solvent extraction, the ligand(s) should be able completely to occupy the primary co-ordination sphere of the metal ion to be extracted. Interactions in the secondary co-ordination sphere are of less importance. Inter-complex Hydrogen Bonding Interactions. Another feature that will be considered is the intermolecular binding between ligands when bound to the metal ion. Thus the intermolecular structures between complex molecules will be considered

  3. Lanthanides and actinides extraction by calixarenes containing CMPO groups

    International Nuclear Information System (INIS)

    Garcia Carrera, A.

    2001-01-01

    In the framework of the French program SPIN concerning the radioactive waste management, researches are performed to develop processes allowing the separation of long-lived radioisotopes in order to their transmutation or their specific conditioning. These studies deal with the extraction and the separation of trivalent lanthanides and actinides in acid solution. Many systems ''calixarene-diluent-aqueous phase'' are examined by extraction liquid-liquid and membrane transport. The extraction efficiency and the selectivity of the synthesized calixarene-CMPO and of the CMPO are compared with these cations, as the nitric acid extraction by these molecules. (A.L.B.)

  4. 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)

  5. Magnetic Circular Dichroism of Porphyrin Lanthanide M3+ Complexes

    Czech Academy of Sciences Publication Activity Database

    Andrushchenko, Valery; Padula, Daniele; Zhivotova, E.; Yamamoto, S.; Bouř, Petr

    2014-01-01

    Roč. 26, č. 10 (2014), s. 655-662 ISSN 0899-0042 R&D Projects: GA ČR GA13-03978S; GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Grant - others:GA AV ČR(CZ) M200550902 Institutional support: RVO:61388963 Keywords : magnetic circular dichroism * lanthanides * porphyrin complexes * density functional theory * sum over state computations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.886, year: 2014

  6. Status of the lanthanides and actinides in the periodic table

    International Nuclear Information System (INIS)

    Holden, N.E.

    1985-01-01

    In extended discussions and correspondence with Ekkehard Fluck, the author was made aware of a problem with the Periodic Table, i.e., which element should be shown in the main table as the representative of the lanthanide series and the actinide series. In earlier discussion, he came to the conclusion that lanthanum and actinium are not the elements which should appear, but rather lutetium and lawrencium are more appropriate for inclusion in their place. This paper will attempt to justify the reasons for the above conclusions. 4 refs

  7. Trispyrazolylborate Complexes: An Advanced Synthesis Experiment Using Paramagnetic NMR, Variable-Temperature NMR, and EPR Spectroscopies

    Science.gov (United States)

    Abell, Timothy N.; McCarrick, Robert M.; Bretz, Stacey Lowery; Tierney, David L.

    2017-01-01

    A structured inquiry experiment for inorganic synthesis has been developed to introduce undergraduate students to advanced spectroscopic techniques including paramagnetic nuclear magnetic resonance and electron paramagnetic resonance. Students synthesize multiple complexes with unknown first row transition metals and identify the unknown metals by…

  8. Magnetic nanoparticle imaging using multiple electron paramagnetic resonance activation sequences

    International Nuclear Information System (INIS)

    Coene, A.; Dupré, L.; Crevecoeur, G.

    2015-01-01

    Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a non-invasive way. Electron Paramagnetic Resonance (EPR) is a promising and sensitive measurement technique for recovering these distributions. In the conventional approach, EPR is applied with a homogeneous magnetic field. In this paper, we employ different heterogeneous magnetic fields that allow to stabilize the solution of the associated inverse problem and to obtain localized spatial information. A comparison is made between the two approaches and our novel adaptation shows an average increase in reconstruction quality by 5% and is 12 times more robust towards noise. Furthermore, our approach allows to speed up the EPR measurements while still obtaining reconstructions with an improved accuracy and noise robustness compared to homogeneous EPR

  9. Enhanced Wireless Power Transmission Using Strong Paramagnetic Response.

    Science.gov (United States)

    Ahn, Dukju; Kiani, Mehdi; Ghovanloo, Maysam

    2014-03-01

    A method of quasi-static magnetic resonant coupling has been presented for improving the power transmission efficiency (PTE) in near-field wireless power transmission, which improves upon the state of the art. The traditional source resonator on the transmitter side is equipped with an additional resonator with a resonance frequency that is tuned substantially higher than the magnetic field excitation frequency. This additional resonator enhances the magnetic dipole moment and the effective permeability of the power transmitter, owing to a phenomenon known as the strong paramagnetic response. Both theoretical calculations and experimental results show increased PTE due to amplification of the effective permeability. In measurements, the PTE was improved from 57.8% to 64.2% at the nominal distance of 15 cm when the effective permeability was 2.6. The power delivered to load was also improved significantly, with the same 10 V excitation voltage, from 0.38 to 5.26 W.

  10. Electron paramagnetic resonance of the ns1 centers in crystals

    International Nuclear Information System (INIS)

    Nistor, S.V.; Ursu, I.

    1993-05-01

    The results of the EPR studies concerning the paramagnetic centers with ns 1 (N=n>2) outer electronic configuration contained in crystals are reviewed. Such centers, with 2 S 1/2 ground state, are produced by electron trapping at impurities of the IB and IIB group or by hole trapping at impurities of the IIIB and IV group of elements. The production and structural properties of such centers consisting of ns 1 ions (atoms) at various sites in the crystal lattice with different configurations of neighbouring defects are discussed in connection with their EPR characteristics. Tables containing the spin Hamiltonian parameters of all ns 1 centers reported in the literature until the end of year 1992 are given. (author). 146 refs, 14 tabs

  11. Modified Mason number for charged paramagnetic colloidal suspensions

    Science.gov (United States)

    Du, Di; Hilou, Elaa; Biswal, Sibani Lisa

    2016-06-01

    The dynamics of magnetorheological fluids have typically been described by the Mason number, a governing parameter defined as the ratio between viscous and magnetic forces in the fluid. For most experimental suspensions of magnetic particles, surface forces, such as steric and electrostatic interactions, can significantly influence the dynamics. Here we propose a theory of a modified Mason number that accounts for surface forces and show that this modified Mason number is a function of interparticle distance. We demonstrate that this modified Mason number is accurate in describing the dynamics of a rotating pair of paramagnetic colloids of identical or mismatched sizes in either high or low salt solutions. The modified Mason number is confirmed to be pseudoconstant for particle pairs and particle chains undergoing a stable-metastable transition during rotation. The interparticle distance term can be calculated using theory or can be measured experimentally. This modified Mason number is more applicable to magnetorheological systems where surface forces are not negligible.

  12. Biophysical dosimetry using electron paramagnetic resonance in human tooth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

    2002-01-01

    Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

  13. The paramagnetic properties of ferromagnetic mixed-spin chain system

    International Nuclear Information System (INIS)

    Hu, Ai-Yuan; Wu, Zhi-Min; Cui, Yu-Ting; Qin, Guo-Ping

    2015-01-01

    The double-time Green's function method is used to investigate the paramagnetic properties of ferromagnetic mixed-spin chain system within the random-phase approximation and Anderson–Callen's decoupling approximation. The analytic expressions of the transverse susceptibility, longitudinal susceptibility and correlation length are obtained under transverse and longitudinal magnetic field. Using the analytic expressions of the transverse and longitudinal susceptibility to fit the experimental results, our results well agree with experimental data and the results from the high temperature series expansion within a simple Padé approximation. - Highlights: • We investigate the magnetic properties of a ferromagnetic mixed-spin chain system. • We use the double-time temperature-dependent Green's function technique. • Different single-ion anisotropy values for different spin values are considered. • Our results agree with experimental data and the results from the other theoretical methods

  14. Radiation silver paramagnetic centers in a beta-alumina crystal

    International Nuclear Information System (INIS)

    Badalyan, A.G.; Zhitnikov, R.A.

    1985-01-01

    Silver paramagnetic centers in a β-alumina crystal, formed after X-ray radiation at 77 K, are investigated by the EPR method. Silver enters the β-alumina crystal, substituting sodium and potassium ions in a mirror plane. Crystals with substitution from 0.1 to 100% of alkali metal ions by Ag + ions are investigated. Silver atomic centers (Ag 0 -centers), formed by electron capture with the Ag + ion, are firstly detected and investigated in the β-alumina. Hole Ag 2+ -centers are investigated and detected in crystals with high concentration of Ag + . By studying the orientation dependence of a g-factor it is established that hole capture by the Ag + ion is accompanied by Ag 2+ ion displacement from the position, Ag + being primarity taken up (Beavers-Roth or anti- Beavers-Roth) to the position between two oxygen ions in the mirror plane

  15. Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    2006-01-01

    The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...... into account a number of individual compartments. The signal dephasing is simulated in a semianalytical way by embedding Monte Carlo simulations in the framework of analytical theory. This approach yields a tool for fast, realistic simulation of the change in the transverse relaxation. The results indicate...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size...

  16. Moessbauer studies on the paramagnetic porton of alkidirat meteorite

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, Huda Mohamed [Department of Physics, Faculty of Science, University of Khartoum, Khartoum (Sudan)

    1995-11-01

    This work was performed on a sample from alkidirat meteorite which fell west of Sudan by means of Moessbauer effect spectrometer. results showed the absence of transition temperature from the paramagnetic state to the magnetic state in the temperature range from 300K down to 16K. Also, it was found that olivine and ortho pyroxene exist together in site M{sup 1}, while clinothyroxene exists alone in site M{sup 2}. Formula for the composition of ortho pyroxene in the sample were also obtained and they were in good agreement with previous studies. The disorder parameter was also calculated and it showed that the pyroxene present in the sample is well-ordered.(Author) 37 refs. , 2 tabs. , 19 figs.

  17. Thermodynamically consistent mesoscopic model of the ferro/paramagnetic transition

    Czech Academy of Sciences Publication Activity Database

    Benešová, Barbora; Kružík, Martin; Roubíček, Tomáš

    2013-01-01

    Roč. 64, Č. 1 (2013), s. 1-28 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GA106/09/1573; GA ČR GAP201/10/0357 Grant - others:GA ČR(CZ) GA106/08/1397; GA MŠk(CZ) LC06052 Program:GA; LC Institutional support: RVO:67985556 Keywords : ferro-para-magnetism * evolution * thermodynamics Subject RIV: BA - General Mathematics; BA - General Mathematics (UT-L) Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-thermodynamically consistent mesoscopic model of the ferro-paramagnetic transition.pdf

  18. Point defects in crystalline zircon (zirconium silicate), ZrSiO4: electron paramagnetic resonance studies

    Science.gov (United States)

    Tennant, W. C.; Claridge, R. F. C.; Walsby, C. J.; Lees, N. S.

    This article outlines the present state of knowledge of paramagnetic defects in crystalline zircon as obtained mainly, but not exclusively, from electron paramagnetic resonance (EPR) studies in crystalline zircon (zirconium silicate, ZrSiO4). The emphasis is on single-crystal studies where, in principle, unambiguous analysis is possible. Firstly, the crystallography of zircon is presented. Secondly, the relationships between available crystal-site symmetries and the symmetries of observed paramagnetic species in zircon, and how these observations lead to unambiguous assignments of point-group symmetries for particular paramagnetic species are detailed. Next, spin-Hamiltonian (SH) analysis is discussed with emphasis on the symmetry relationships that necessarily exist amongst the Laue classes of the crystal sites in zircon, the paramagnetic species occupying those sites and the SH itself. The final sections of the article then survey the results of EPR studies on zircon over the period 1960-2002.

  19. Efficient Separation of Lanthanides Using Poly (Styrene-Divinyl Benzene) Aminated Anion Exchanger

    International Nuclear Information System (INIS)

    Borai, E.H.; Hassan, R.S.; El- Dessouky, M.I.; Ghonem, A.

    2008-01-01

    New chromatographic method was developed for the determination and separation of lanthanides using AS4A anionic column. The behavior of the column towards lanthanides was studied through many parameters, From the data obtained it is found that, affinity of the column toward investigated ions increase by increasing eluent concentration and it decrease retention factors. With the two investigated eluent (oxalic and citric acids), elution order for lanthanide elements was obtained in their atomic number from La to Lu. Retention times and retention orders obtained at these conditions clearly show that, lanthanides in AS4A are displaced according to anion exchange mechanism. More over separation of lanthanides using AS4A was studied using isocratic and gradient elution programs. Light and the first intermediate lanthanide elements were separated successfully by applying a gradient program containing 70% oxalic acid (100 mM) and 30% water. The problem of separation for heavy and the last intermediate lanthanide elements was solved using 100 mM alpha hydroxy isobutyric acid (α-HIBA)

  20. 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)

  1. Lanthanide-based fluorescent tracers in complex media

    International Nuclear Information System (INIS)

    Brichart, Thomas

    2014-01-01

    Tracers are objects allowing the determination of the position or the distribution of a product; tracers are currently used in a great variety of domains. Despite the fact that each field has it's own specifications, it is possible to find tracers in medicine (contrast agents), anti-counterfeiting or geological exploration. We have developed lanthanide complex tracers for oil field injection waters. Those tracers, derived from the DOTA, have been detected at concentration lower than 1 ppb, thanks to a simple and compact apparatus. This detection has been made possible by the use of time-resolved fluorescence spectroscopy, this technique allows us to get rid of the background noise created by the intrinsic fluorescence of oil residues that are present in production waters. We also demonstrated how we can, through a reverse microemulsion synthesis, encapsulate several different dyes inside a single nanoparticle composed of a gold core and a silica shell. We showed as well, how those particles can be used as smart tracers to gather data, such as temperature, pH, solvents, etc. inside the well. Finally the use of lanthanides and scale inhibitors properties allowed us to create a simple and fast dosing protocol of such scale inhibitors in injection waters. This dosage will then allow the quick adjustment of their concentration inside each well. (author) [fr

  2. Lanthanide-IMAC enrichment of carbohydrates and polyols.

    Science.gov (United States)

    Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

    2014-03-01

    In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions. Copyright © 2013 John Wiley & Sons, Ltd.

  3. 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

  4. Thermochemistry of selected lanthanide and actinide hydroxycarbonates and carbonates

    International Nuclear Information System (INIS)

    Merli, L.; Fuger, J.

    1996-01-01

    Lanthanide and actinide carbonates and hydroxycarbonates are, together with the hydroxides, important compounds in the problematics of high level waste disposal, since such and related compounds may appear as solid phases as a result of the interaction of the waste with natural waters. Experimental results on the stability and relationships between these compounds, particularly the hydroxycarbonates, are relatively fragmentary and arise mainly from solubility measurements, and, to a lesser extent, from enthalpy of formation determinations. We report here the enthalpies of formation of a number of well characterized hydroxycarbonates of trivalent lanthanides, namely those of neodymium, samarium, dysprosium, ytterbium, and of americium, as well as that of neodymium sesquicarbonate, using solution calorimetry in acidic media. The obtained values are discussed in the light of literature data on existing solubility and enthalpy of formation of related compounds. Our results have been obtained with a newly conceived sealed calorimeter, briefly described in the paper, in which the CO 2 produced during the dissolution reaction is maintained in solution, thus eliminating the problem of the kinetically slow evolution of the CO 2 (g) from the medium and the irregularities in the associated thermal effect. (orig.)

  5. Energetic lanthanide complexes: coordination chemistry and explosives applications

    International Nuclear Information System (INIS)

    Manner, V W; Barker, B J; Sanders, V E; Laintz, K E; Scott, B L; Preston, D N; Sandstrom, M; Reardon, B L

    2014-01-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  6. Lanthanide complexes that respond to changes in cyanide concentration in water

    International Nuclear Information System (INIS)

    Routledge, Jack D.; Zhang, Xuejian; Connolly, Michael; Tropiano, Manuel; Blackburn, Octavia A.; Beer, Paul D.; Aldridge, Simon; Faulkner, Stephen; Kenwright, Alan M.

    2017-01-01

    Cyanide ions are shown to interact with lanthanide complexes of phenacylDO3A derivatives in aqueous solution, giving rise to changes in the luminescence and NMR spectra. These changes are the consequence of cyanohydrin formation, which is favored by the coordination of the phenacyl carbonyl group to the lanthanide center. These complexes display minimal affinity for fluoride and can detect cyanide at concentrations less than 1 μm. By contrast, lanthanide complexes with DOTAM derivatives display no affinity for cyanide in water, but respond to changes in fluoride concentration. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Lanthanide complexes that respond to changes in cyanide concentration in water

    Energy Technology Data Exchange (ETDEWEB)

    Routledge, Jack D.; Zhang, Xuejian; Connolly, Michael; Tropiano, Manuel; Blackburn, Octavia A.; Beer, Paul D.; Aldridge, Simon; Faulkner, Stephen [Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford (United Kingdom); Kenwright, Alan M. [Department of Chemistry, Durham University (United Kingdom)

    2017-06-26

    Cyanide ions are shown to interact with lanthanide complexes of phenacylDO3A derivatives in aqueous solution, giving rise to changes in the luminescence and NMR spectra. These changes are the consequence of cyanohydrin formation, which is favored by the coordination of the phenacyl carbonyl group to the lanthanide center. These complexes display minimal affinity for fluoride and can detect cyanide at concentrations less than 1 μm. By contrast, lanthanide complexes with DOTAM derivatives display no affinity for cyanide in water, but respond to changes in fluoride concentration. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. 2,2',-bipyridine and 1,10-phenanthroline complexes of lanthanide(III) trifluoroacetates

    International Nuclear Information System (INIS)

    Misra, S.N.; Singh, M.

    1983-01-01

    The syntheses and characterization of lanthanide(III) triflloroacetate complexes with 2,2'-bipyridine and 1,10-phenanthroline are reported. Lanthanide(III) trifluoroacetates yield compounds of the type Ln(CF 3 COO) 3 .bipy or phen with 2,2'-bipyridine and 1,10-phenanthroline. Their properties and structures have been studied using chemical analyses. electronic and infrared spectra. Thermal analysis of a few complexes have also been done. The infrared data show that the trifluoroacetate group acts as a bidentate ligand making the coordination number of lanthanide eight. (author)

  9. A lanthanide complex with dual biosensing properties: CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts) with europium DOTA-tetraglycinate.

    Science.gov (United States)

    Coman, Daniel; Kiefer, Garry E; Rothman, Douglas L; Sherry, A Dean; Hyder, Fahmeed

    2011-12-01

    Responsive contrast agents (RCAs) composed of lanthanide(III) ion (Ln3R) complexes with a variety of1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA4S) derivatives have shown great potential as molecular imaging agents for MR. A variety of LnDOTA–tetraamide complexes have been demonstrated as RCAs for molecular imaging using chemical exchange saturation transfer (CEST). The CEST method detects proton exchange between bulk water and any exchangeable sites on the ligand itself or an inner sphere of bound water that is shifted by a paramagnetic Ln3R ion bound in the core of the macrocycle. It has also been shown that molecular imaging is possible when the RCA itself is observed (i.e. not its effect on bulk water) using a method called biosensor imaging of redundant deviation in shifts (BIRDS). The BIRDS method utilizes redundant information stored in the nonexchangeable proton resonances emanating from the paramagnetic RCA for ambient factors such as temperature and/or pH.Thus, CEST and BIRDS rely on exchangeable and nonexchangeable protons, respectively, for biosensing. We posited that it would be feasible to combine these two biosensing features into the same RCA (i.e. dual CEST and BIRDS properties). A complex between europium(III) ion (Eu3R) and DOTA–tetraglycinate [DOTA–(gly)S4] was used to demonstrate that its CEST characteristics are preserved, while its BIRDS properties are also detectable. The in vitro temperature sensitivity of EuDOTA–(gly)S4 was used to show that qualitative MR contrast with CEST can be calibrated using quantitative MR mapping with BIRDS, thereby enabling quantitative molecular imaging at high spatial resolution.

  10. Magnetic resonance studies of isotopically labeled paramagnetic proteins: (2FE-2S) ferredoxins

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, H.; Xia, B.; Chae, Y.K.; Westler, W.M.; Markley, J.L. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    Recent developments in NMR spectroscopy, especially multidimensional, multinuclear NMR techniques, have made NMR the most versatile tool available for studying protein structure and function in solution. Unlike diamagnetic proteins, paramagnetic proteins contain centers with unpaired electrons. These unpaired electrons interact with magnetic nuclei either through chemical bonds by a contact mechanism or through space by a pseudocontact mechanism. Such interactions make the acquisition and analysis of NMR spectra of paramagnetic proteins more challenging than those of diamagnetic proteins. Some NMR signals from paramagnetic proteins are shifted outside the chemical shift region characteristic of diamagnetic proteins; these {open_quotes}hyperfine-shifted{close_quotes} resonances originate from nuclei that interact with unpaired electrons from the paramagnetic center. The large chemical shift dispersion in spectra of paramagnetic proteins makes it difficult to excite the entire spectral window and leads to distortions in the baseline. Interactions with paramagnetic centers shorten T{sub 1} and T{sub 2} relaxation times of nuclei; the consequences are line broadening and lower spectral sensitivity. Scalar (through bond) and dipolar (through space) interactions between pairs of nuclei are what give rise to crosspeak signals in multi-dimensional NMR spectra of small diamagnetic proteins. When such interactions involve a nucleus that is strongly relaxed by interaction with a paramagnetic center, specialized methods may be needed for its detection or it may be completely undetectable by present nD NMR methods.

  11. Electron paramagnetic resonance (EPR) in characterization of rocks and minerals

    Energy Technology Data Exchange (ETDEWEB)

    Valezi, D.F.; Mauro, E. di [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Lab. de Fluorescencia e Ressonaancia Paramagnetica Eletronica (LAFLURPE); Zaia, D.A.M.; Carneiro, C.E.A. [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Costa, A.C.S. da [Universidade Estadual de Maringa (UEM), PR (Brazil). Centro de Ciencias Agrarias. Dept. de Agronomia

    2011-07-01

    Full text. his work is based on the study of several stones and minerals from the Parana state, Brazil. They were analyzed by the Electron Paramagnetic Resonance (EPR) technique. The measurements were made on a spectrometer JEOL (JES-PE-3X), operating on X-band and at room temperature, with the exception of the mineral Goethite, which was measured with temperature variation. In all the samples were determined spectroscopic factors (or g factor) and line widths of paramagnetic species. A great number of the samples showed in their spectra, the presence of iron complexes. Phyllite and shale showed a resonance signal with approximately g = 2, and line width with about 1000 Gauss, which indicates the presence of the hematite mineral hematite in these rocks. Shale and coal samples showed the presence of free radical, it was identified as a very intense signal, centered at about g = 2.003. Phyllite sample showed in its spectra a resonance signal between the third and fourth line of the g marker (Mg O:Mn{sup 2+}) used in the measurements, and also a signal at g = 4.3, these characteristics may indicate the presence of Kaolinite in the sample. Limestone showed a signal with line width of about 600 Gauss, centered around g = 2, this signal is probably due to a mixture of ferrihydrite and some other compound, besides the presence of manganese, displaying a spectra with its six peculiar lines, due to hyperfine splitting. The two different types of limestone presented a overlap of two distinct spectra lines for the manganese, in the first limestone sample, rich in calcite, the existence of these different spectra is a result of the manganese substitution in a single site with different orientations of the calcite; the other limestone sample, this one abundant in dolomite, the existence of these different spectra is the result of the manganese substitution in different dolomite sites, taking the place of calcium and or of the magnesium. Now, we are focusing our research in the

  12. Flexible Photonics: Polymer LEDs Made from Monochromatic Red Emitting Lanthanide/Polymer Blends. Phase 1

    National Research Council Canada - National Science Library

    O'Regan, Marie

    1999-01-01

    .... Spectrally pure, red emitting flexible LEDs have been fabricated. Close to a four-fold increase in device efficiency is obtained when a suitable lanthanide complex is blended with the semi-conducting host polymer...

  13. Detection of Fluorescence for Lanthanides in LiCl-KCl Molten Salt Medium

    International Nuclear Information System (INIS)

    Im, Hee Jung; Kim, Tack Jin; Song, Kyu Seok; Jee, Kwang Yong

    2007-01-01

    In the electrorefining step of the pyrochemical process, actinide ions dissolved in the LiCl-KCl eutectic salt are recovered as pure actinide metals at a cathode for a re-use as a nuclear fuel from the aspect of its nonproliferation of the nuclear fuel cycles. The lanthanide species dissolved in the LiCl-KCl eutectic salt play an important role in an effective metal purification during the electrorefining step, so it is necessary to understand the chemical and physical behaviors of lanthanides in molten salt. The in situ spectroscopic measurement system and studies according to temperature changes are essential for better understandable information. To our knowledge, the absorption studies of lanthanides at high temperatures have been reported before, but the fluorescence studies of those at high temperature are not reported yet. We will discuss here the fluorescence behaviors of lanthanides in LiCl-KCl molten salt medium according to a changing temperature

  14. Separation of interfering elements in the neutron activation analysis of lanthanides in geological materials

    International Nuclear Information System (INIS)

    Saiki, M.

    1988-01-01

    A chemical procedure has been developed for the separation of U, Th, Fe, Sc, Na,Ta, and Mo which interfere in the neutron activation analysis of the lanthanide elements in geological materials. This procedure is based on the solvent extraction of interferents using a solution of tetracycline in benzyl alcohol. The lanthanide elements remaining in the aqueous phase are coprecipitated on calcium oxalate or ferric hydroxide for irradiation and subsequent determination by gamma ray spectrometry. The chemical separation procedure was applied in the analysis of lanthanides in two international geological reference materials GSP-1 (USGS), GS-N (CRPG) and in the analysis of a volcanic rock from Pocos de Caldas, MG, Brazil. The sensitivities for all the lanthanides were determined. (author) [pt

  15. Multicolour synthesis in lanthanide-doped nanocrystals through cation exchange in water

    KAUST Repository

    Han, Sanyang; Qin, Xian; An, Zhongfu; Zhu, Yihan; Liang, Liangliang; Han, Yu; Huang, Wei; Liu, Xiaogang

    2016-01-01

    lanthanide-doped luminescent nanomaterials have relied on direct synthesis requiring stringent controls over crystal nucleation and growth at elevated temperatures. Here we demonstrate the use of a cation exchange strategy for expeditiously accessing large

  16. FY17 Progress in Modeling of Lanthanide Transport in Metallic Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Cetin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Matthews, Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-19

    A critical review of fuel-clad-chemical interactions along with modelling requirements is published. The mechanism of lanthanide transport is studied experimentally (NEUP collaboration) and using simulations and initial results are published in Refs.

  17. Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

    International Nuclear Information System (INIS)

    Hassan, S.S.M.; Mahmoud, W.H.

    1982-01-01

    Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations ( 4 L mol -1 cm -1 ) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 μg/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 μg to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated

  18. Adducts of between lanthanide (III) trifluoromethanesulfonate and yttrium (III) and tetramethylene sulphoxide ligand

    International Nuclear Information System (INIS)

    Assis Araujo, F. de.

    1983-01-01

    The synthesis, characterization and spectroscopic properties of lanthanides trifluoromethanesulfonate complexes with tetramethylenesulfoxide (TMSO), are described. The interpretation of X-ray powder patterns show one isomorphous series. (M.J.C.) [pt

  19. Lanthanide Selective Sorbents: Self-Assembled Monolayers on Mesoporous Supports (SAMMS)

    Energy Technology Data Exchange (ETDEWEB)

    Fryxell, Glen E.; Wu, Hong; Lin, Yuehe; Shaw, Wendy J.; Birnbaum, Jerome C.; Linehan, John C.; Nie, Zimin; Kemner, K. M.; Kelly, Shelley

    2004-11-01

    Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a ''hard'' anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized

  20. Nature of the magnetic susceptibility of dysprosium. Paramagnetic susceptibility of dysprosium - yttrium alloys

    International Nuclear Information System (INIS)

    Demidov, V.G.; Levitin, R.Z.; Chistyakov, O.D.

    1976-01-01

    The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature

  1. Ferro-paramagnetic coupled resonant modes in GdEuCuO4

    International Nuclear Information System (INIS)

    Fainstein, A.; Tovar, M.

    1990-01-01

    Two paramagnetic resonances were observed in compound GdEuCuO 4 : one was originated in trivalent gadolinium paramagnetism, while the other is associated to a weak ferromagnetic mode in Cu-O planes. In this work, experimental results are presented that show an anisotropy and a strongly anomalous temperature dependence of Gd 3+ . A theoretical model was introduced which explains the data in terms of coupled ferro-paramagnetic resonant modes originated in spin exchange coupling of Cu and Gd. (Author). 9 refs., 4 figs

  2. Size-dependent concentration of N0 paramagnetic centres in HPHT nanodiamonds

    Directory of Open Access Journals (Sweden)

    B.V. Yavkin, G.V. Mamin, M.R. Gafurov, S.B. Orlinskii

    2015-12-01

    Full Text Available Size-calibrated commercial nanodiamonds synthesized by high-pressure high-temperature (HPHT technique were studied by high-frequency W- and conventional X-band electron paramagnetic resonance (EPR spectroscopy. The numbers of spins in the studied samples were estimated. The core-shell model of the HPHT nanodiamonds was proposed to explain the observed dependence of the concentration of the N0 paramagnetic centers. Two other observed paramagnetic centers are attributed to the two types of structures in the nanodiamond shell.

  3. 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

  4. Citrate-based open-quotes Talspeakclose quotes actinide-lanthanide separation process

    International Nuclear Information System (INIS)

    Del Cul, G.D.; Toth, L.M.; Bond, W.D.

    1997-01-01

    Lanthanide elements are produced in relatively high yield by fission of 235 U. Almost all the lanthanide isotopes decay to stable nonradioactive lanthanide isotopes in a relatively short time. Consequently, it is highly advantageous to separate the relatively small actinide fraction from the relatively large quantities of lanthanide isotopes. The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. Previous work based on the use of lactic or glycolic acid has shown deleterious effects of some impurity ions such as zirconium(IV), even at concentrations on the order of 10 -4 M. Other perceived problems were the need to maintain the pH and reagent concentrations within a narrow range and a significant solubility of the organic phase at high carboxylic acid concentrations. The authors' cold experiments showed that replacing the traditional extractants glycolic or lactic acid with citric acid eliminates or greatly reduces the deleterious effects produced by impurities such as zirconium. An extensive series of batch tests was done using a wide range of reagent concentrations at different pH values, temperatures, and contact times. The results demonstrated that the citrate-based TALSPEAK can tolerate appreciable changes in pH and reagent concentrations while maintaining an adequate lanthanide extraction. Experiments using a three-stage glass mixer-settler showed a good lanthanide extraction, appropriate phase disengagement, no appreciable deleterious effects due to the presence of impurities such as zirconium, excellent pH buffering, and no significant loss of organic phase

  5. SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

    Science.gov (United States)

    Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

    1963-02-12

    This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

  6. 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.

  7. Studies on trivalent lanthanide complexes of bis-vanillin p-phenylenediamine

    International Nuclear Information System (INIS)

    Shahma, Abu; Ahmad, Naseer

    1983-01-01

    The coordination interaction of lanthanide(III) chlorides with bis-vanillin o-phenylenediamine was studied by Ansari and Ahmad (1977). It was thought fruitful to compare these with the complexes of trivalent lanthanide ions with bis-vanillin p-phenylenediamine. The newly synthesized complexes were subjected to elemental, thermogravimetric and differential thermal analyses and their melting points, magnetic susceptibilities, molar conductances determined and infrared and electronic spectra taken. (author)

  8. Lanthanide alkyl and silyl compounds: Synthesis, reactivity and catalysts for green

    Energy Technology Data Exchange (ETDEWEB)

    Pindwal, Aradhana [Iowa State Univ., Ames, IA (United States)

    2016-01-01

    The last few decades have witnessed enormous research in the field of organometallic lanthanide chemistry. Our research group has developed a few rare earth alkyl compounds containing tris(dimethylsilyl)methyl ligand and explored their reactivity. This thesis focusses on extending the study of lanthanide alkyl and silyl compounds to develop strategies for their synthesis and explore their reactivity and role as catalysts in processes such as hydrosilylation and cross-dehydrocoupling.

  9. Application of lanthanide ions doped in different glasses

    International Nuclear Information System (INIS)

    Dhondiyal, Charu Chandra

    2015-01-01

    The transfer of optical excitation energy from one ion/molecule to another ion/molecule has proved to be of potential importance in industrial application as well as research. Rare earth elements (RE) although not as rare as some of them occur more prevalently then other well known material (e.g. silver, tin, tungsten) are special group of elements of the periodic table comprising lanthanide series (from lanthanum to lutetium) and actinide series (from actinium to lawrencium). Most of the actinides are highly radioactive hence their uses are limited. Fluorescence is the particular optical property of lanthanide (RE) ions. The narrow absorption and emission lines exhibited by the RE ions in crystals, glasses and solutions have always made these ions attractive as sensitive probes of solids and liquid state and also makes them useful in laser technology, CRT displays, UV to visible converters and optical communications etc. In recent years there has been a special interest to study the properties and applications of rare earth doped in glasses. Lanthanide ions in glasses play an important role, especially by retaining their emission capabilities, in the host matrix. Glass as a dielectric material plays an important role in science and industry. Its chemical, physical and particular optical properties make it suitable for applications such as opto-electronic materials, laboratory equipment, laser gain media, etc. Photoluminescence from rare earth doped glasses are of major interest in the research area of optoelectronic device applications like phosphors, display monitors, lasers and amplifiers for communication systems. Now a days, development of optical devices based on rare-earth ions doped materials is one of the interesting fields of research. Rare earth doped glasses are widely used as laser materials, optical amplifiers, optical memory devices, magneto-optical devices, medical lasers, eye safe lasers, flat panel displays, fluorescent lamps, white LED's etc

  10. Lanthanides in molecular magnetism: old tools in a new field.

    Science.gov (United States)

    Sorace, Lorenzo; Benelli, Cristiano; Gatteschi, Dante

    2011-06-01

    In this tutorial review we discuss some basic aspects concerning the magnetic properties of rare-earth ions, which are currently the subject of a renovated interest in the field of molecular magnetism, after the discovery that slow relaxation of the magnetization at liquid nitrogen temperature can occur in mononuclear complexes of these ions. Focusing on Dy(III) derivatives a tutorial discussion is given of the relation of the crystal field parameters, which determine the anisotropy of these systems and consequently their interesting magnetic properties, with the geometry of the coordination sphere around the lanthanide centre and with the pattern of f orbitals. The problem of systems of low point symmetry is also addressed by showing how detailed single crystal investigation, coupled to more sophisticated calculation procedures, is an absolute necessity to obtain meaningful structure-property relationships in these systems.

  11. NMR studies of structures of lanthanide dicarboxylate complexes in solution

    International Nuclear Information System (INIS)

    Choppin, G.R.; Kullberg, L.

    PMR pand 13 C shift data were measured for complexes of Pr(III), Eu(III) and Yb(III) with ethylene 1,2-dioxydiacetate (EDODA), ethylene 1,2-dithiodiacetate (EDSDA), and ethylene, 1,2-diaminodiacetate (EDDA). Solubility problems limited analysis of the EDSDA and EDDA data to qualitative evaluation. In the EDSDA complexes, the data indicate that the sulfur atoms do not participate in bonding to the lanthanide cations. Moreover, both carboxylate groups seem to bind Pr and Eu while Yb interacts with only a single carboxylate group. The EDDA complexes are tetradentate with long lived (NMR scale) Ln-N bonds. Shift theory allowed more quantitative analysis of the EDODA complexes. They are tetradentate with a puckered chelate ring and Ln-O(ether) distances of 2.3 A

  12. Lanthanide and actinide ion phytoextraction: investigations of biosorption chemistry

    International Nuclear Information System (INIS)

    Rayson, Gary D.; Serna, Debbie D.; Moore, Jessica L.

    2009-01-01

    Investigations of the chemical interactions responsible for passive biosorption of a lanthanide (Eu (III)) and an actinide (U (VI)) metal ion is described. Spectroscopic methods for the elucidation of chemical functionalities on cultured anther cell walls from the plant Datura innoxia include metal ion luminescence measurements. These have revealed the presence of distinctly different binding environments involving one, two, and three carboxylate moieties for Eu (III) and UO 2 2+ binding and sulfonates (or sulfates) and phosphates for sequestration of Eu (III) on the uranyl ion, respectively. Additional investigations of the apparent affinities of these metals to this material have revealed the presence of both low and high affinity sites for the binding of Eu (III) with weak electrostatic attractions proposed for binding at high metal concentrations (i.e., low affinities) and surface coordination interactions responsible for higher affinities. Conversely, total uranyl ion binding revealed only a single distribution of interactions based on apparent affinities. (author)

  13. Luminescence properties of isomeric and tautomeric lanthanide pyridinedicarboxylates

    International Nuclear Information System (INIS)

    Puntus, L.N.; Zolin, V.F.; Babushkina, T.A.; Kutuza, I.B.

    2004-01-01

    The luminescence and PMR spectra of europium salts of six isomers of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-pyridinedicarboxylic acids (PDA) had been studied. The distribution of the effective charge in the nearest surroundings of the Eu 3+ ion in these salts was evaluated from Stark splittings of electronic transitions. The values of relative integral intensities of electronic transitions 5 D 0 - 7 F J (J=0-4) in the luminescence spectra were reported. Compounds investigated were divided into three subgroups taking into account the details of the structure of the ligands and details of the luminescence spectra. The ligand coordination manners as well as the strength of interaction between lanthanide ion and ligands were confirmed by data of the PMR and IR spectroscopy

  14. 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

  15. Chelation studies involving decontamination of light lanthanides by polyaminopolycarboxylic

    International Nuclear Information System (INIS)

    Hassan, N.E.H.

    1985-01-01

    The present thesis constitutes chelation studies involving decontamination of light lanthanides, cobalt , and uranium with 2,2-bis-acryloyliminomethylene- acid (BAETA) using the spectrophotometric method. the work carried out aimed to clear up the effectiveness of BAETA as a decontaminating agent for radioactive nuclides from human body . the thesis includes a general introduction , outlines the aim of work and contains three main chapters . the results of the work are discussed at the end of the thesis. the first chapter deals with a comprehensive survey of the relevant literature. this includes the metabolism and toxicity of cerium, uranium, cobalt and Ln +3 elements, general methodologies of internal decontamination, choice and effectiveness of chelating agents

  16. Migration study of actinides and lanthanides in compacted bentonite

    International Nuclear Information System (INIS)

    Sastrowardoyo, P.B.; Susilowati, D.; Suganda, D.

    1998-01-01

    Migration study of actinide and lanthanide elements in compacted bentonite has been conducted. Data of these elements mobilities have been shown, and it is showed that the diffusion coefficient was varied as the function of solution phase condition as well as the origin/composition of bentonite. It is showed that the diffusion coefficient decreased by the increasing of density, as well as the increasing of montmorillonite content in bentonite. The ratio of bentonite/silica-sand used was related to the increasing of elements mobility. In many case the difference of diffusion coefficient was related to the variation of pH and redox condition, as well as the presence of complexant in solution phase. The Lower diffusion coefficient could give the higher retardation factor, which is a favourable factor to retard the radionuclides release from a disposal facility to geosphere. (author)

  17. Application of electron paramagnetic resonance to identify irradiated soybean

    International Nuclear Information System (INIS)

    Bhaskar, S.; Behere, Arun; Sharma, Arun

    2006-01-01

    Full text: Electron paramagnetic resonance spectroscopy was applied to study free radicals in soy bean seed after gamma irradiation and to establish the potential of these radiation induced free radicals as the indicator of the radiation treatment. The radiation doses administered to the samples were 1 to 30 kGy. A stable doublet signal was detected at g = 2.0279 with hyperfine coupling constant of 2.8 mT, produced only by radiolysis. This signal can be used to identify irradiated soy bean seed samples. With the increase of the radiation dose the central line intensity and the intensities of the satellite lines showed almost a linear rise having linear correlation factors of 0.99724 and 0.99996, respectively. Thermal treatment at 373 deg K in air was studied. No line specific to thermolysis was observed. The spectrometer was operated with power 0.253 mW, microwave frequency 9.74 GHz, modulation frequency 100 kHz and scan range 10 mT. To study the stability of the signal, EPR spectra were obtained from the irradiated skin part of soy bean seeds samples following 1 and 90 days of storage after radiation treatment. The two satellite lines of g left = 2.0279 and g right 1.99529 were detected in all samples. This suggests that the signal is associated with a stable radical and therefore, the detection of a particular free radical as a marker of irradiation is proposed

  18. Thermophysical properties of paramagnetic Fe from first principles

    Science.gov (United States)

    Ehteshami, Hossein; Korzhavyi, Pavel A.

    2017-12-01

    A computationally efficient, yet general, free-energy modeling scheme is developed based on first-principles calculations. Finite-temperature disorder associated with the fast (electronic and magnetic) degrees of freedom is directly included in the electronic structure calculations, whereas the vibrational free energy is evaluated by a proposed model that uses elastic constants to calculate average sound velocity of the quasiharmonic Debye model. The proposed scheme is tested by calculating the lattice parameter, heat capacity, and single-crystal elastic constants of α -, γ -, and δ -iron as functions of temperature in the range 1000-1800 K. The calculations accurately reproduce the well-established experimental data on thermal expansion and heat capacity of γ - and δ -iron. Electronic and magnetic excitations are shown to account for about 20% of the heat capacity for the two phases. Nonphonon contributions to thermal expansion are 12% and 10% for α - and δ -Fe and about 30% for γ -Fe. The elastic properties predicted by the model are in good agreement with those obtained in previous theoretical treatments of paramagnetic phases of iron, as well as with the bulk moduli derived from isothermal compressibility measurements [N. Tsujino et al., Earth Planet. Sci. Lett. 375, 244 (2013), 10.1016/j.epsl.2013.05.040]. Less agreement is found between theoretically calculated and experimentally derived single-crystal elastic constants of γ - and δ -iron.

  19. Effects of water on fingernail electron paramagnetic resonance dosimetry.

    Science.gov (United States)

    Zhang, Tengda; Zhao, Zhixin; Zhang, Haiying; Zhai, Hezheng; Ruan, Shuzhou; Jiao, Ling; Zhang, Wenyi

    2016-09-01

    Electron paramagnetic resonance (EPR) is a promising biodosimetric method, and fingernails are sensitive biomaterials to ionizing radiation. Therefore, kinetic energy released per unit mass (kerma) can be estimated by measuring the level of free radicals within fingernails, using EPR. However, to date this dosimetry has been deficient and insufficiently accurate. In the sampling processes and measurements, water plays a significant role. This paper discusses many effects of water on fingernail EPR dosimetry, including disturbance to EPR measurements and two different effects on the production of free radicals. Water that is unable to contact free radicals can promote the production of free radicals due to indirect ionizing effects. Therefore, varying water content within fingernails can lead to varying growth rates in the free radical concentration after irradiation-these two variables have a linear relationship, with a slope of 1.8143. Thus, EPR dosimetry needs to be adjusted according to the water content of the fingernails of an individual. When the free radicals are exposed to water, the eliminating effect will appear. Therefore, soaking fingernail pieces in water before irradiation, as many researchers have previously done, can cause estimation errors. In addition, nails need to be dehydrated before making accurately quantitative EPR measurements. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  20. Using an electron paramagnetic resonance method for testing motor oils

    Energy Technology Data Exchange (ETDEWEB)

    Krais, S; Tkac, T

    1982-01-01

    Using an ER-9 spectrometer from the Karl Zeiss company, the relative effectiveness is studied of antioxidation additives. Motor oils of the E group, M6AD, 465, M6AD, 466, M6AD 467, 15 W/40, S-3/2 M/4, R-950, which contain the antioxidation additive were tested in Petter AV-1 motors at a temperature of 50 degrees for 120 hours and Petter AVB at a temperature of 90 degrees for 53 hours. To measure the concentration of free radicals of the antioxidation additives one part of 2,2-diphenyl-1-picrylhydrazine (I), which forms stable dimagnetic products with the radicals of the antioxidation additives was introduced into each three parts of the oil. The reduction in the intensity of the signal of I was the measure of the radical concentration. The spectrum was taken for 1 to 2 minutes. The graphs of the dependence of the electron paramagnetic resonance on the test time and the concentration of I are built. The beginning and end of the induction period of oxidation of the oils and the change in the hourly activity of the PP was recorded.

  1. Spin dynamics of EuS in the paramagnetic phase

    International Nuclear Information System (INIS)

    Chaudhury, R.; Shastry, B.S.

    1988-07-01

    The spin dynamics of the semiclassical Heisenberg model on the fcc lattice, with ferromagnetic interaction in the first neighbour shell, anti-ferromagnetic interaction in the second neighbour shell and which undergoes a ferromagnetic transition, is studied in the paramagnetic phase at the temperature 1.1 T c using the Monte-Carlo molecular dynamics technique. The important quantities calculated are the dynamic structure function S(q-vector,ω) and the spin auto-correlation function i (O)·S-vector i (t)>. Our results for S(q-vector,ω) show the existence of purely diffusive modes in the low q regime. For q-vector close to the zone boundary, our calculated S(q-vector,ω) shows multi-peaked structure, signifying damped propagating modes. This result disagrees with the theoretical predictions of Young and Shastry and also of Lindgard. Our results for S(q-vector,ω) in the entire q-vector-space are in good qualitative and quantitative agreement with the recent neutron scattering experiments of Boni et al. and also Bohn et al. Our calculated auto-correlation function shows a diffusive behaviour temporally. (author). 15 refs, 5 figs

  2. THz Electron Paramagnetic Resonance / THz Spectroscopy at BESSY II

    Directory of Open Access Journals (Sweden)

    Karsten Holldack

    2016-02-01

    Full Text Available The THz beamline at BESSY II employs high power broadband femto- to picosecond long THz pulses for magneto-optical THz and FIR studies. A newly designed set-up exploits the unique properties of ultrashort THz pulses generated by laser-energy modulation of electron bunches in the storage ring or alternatively from compressed electron bunches. Experiments from 0.15 to 5 THz (~ 5 – 150 cm-1 may be conducted at a user station equipped with a fully evacuated high resolution FTIR spectrometer (0.0063 cm-1, lHe cooled bolometer detectors, a THz TDS set-up and different sample environments, including a superconducting high field magnet (+11 T - 11T with variable temperature insert (1.5 K – 300 K, a sample cryostat and a THz attenuated total reflection chamber.  Main applications are Frequency Domain Fourier transform THz-Electron Paramagnetic Resonance (FD-FT THz-EPR, THz-FTIR spectroscopy and optical pump - THz probe time domain spectroscopy (TDS, with sub-ps time resolution.

  3. Cation Binding to Xanthorhodopsin: Electron Paramagnetic Resonance and Magnetic Studies.

    Science.gov (United States)

    Smolensky Koganov, Elena; Leitus, Gregory; Rozin, Rinat; Weiner, Lev; Friedman, Noga; Sheves, Mordechai

    2017-05-04

    Xanthorhodopsin (xR) is a member of the retinal protein family and acts as a proton pump in the cell membranes of the extremely halophilic eubacterium Salinibacter ruber. In addition to the retinal chromophore, xR contains a carotenoid, which acts as a light-harvesting antenna as it transfers 40% of the quanta it absorbs to the retinal. Our previous studies have shown that the CD and absorption spectra of xR are dramatically affected due to the protonation of two different residues. It is still unclear whether xR can bind cations. Electron paramagnetic resonance (EPR) spectroscopy used in the present study revealed that xR can bind divalent cations, such as Mn 2+ and Ca 2+ , to deionized xR (DI-xR). We also demonstrate that xR can bind 1 equiv of Mn 2+ to a high-affinity binding site followed by binding of ∼40 equiv in cooperative manner and ∼100 equiv of Mn 2+ that are weakly bound. SQUID magnetic studies suggest that the high cooperative binding of Mn 2+ cations to xR is due to the formation of Mn 2+ clusters. Our data demonstrate that Ca 2+ cations bind to DI-xR with a lower affinity than Mn 2+ , supporting the assumption that binding of Mn 2+ occurs through cluster formation, because Ca 2+ cations cannot form clusters in contrast to Mn 2+ .

  4. Enamel dose calculation by electron paramagnetic resonance spectral simulation technique

    International Nuclear Information System (INIS)

    Dong Guofu; Cong Jianbo; Guo Linchao; Ning Jing; Xian Hong; Wang Changzhen; Wu Ke

    2011-01-01

    Objective: To optimize the enamel electron paramagnetic resonance (EPR) spectral processing by using the EPR spectral simulation method to improve the accuracy of enamel EPR dosimetry and reduce artificial error. Methods: The multi-component superimposed EPR powder spectral simulation software was developed to simulate EPR spectrum models of the background signal (BS) and the radiation- induced signal (RS) of irradiated enamel respectively. RS was extracted from the multi-component superimposed spectrum of irradiated enamel and its amplitude was calculated. The dose-response curve was then established for calculating the doses of a group of enamel samples. The result of estimated dose was compared with that calculated by traditional method. Results: BS was simulated as a powder spectrum of gaussian line shape with the following spectrum parameters: g=2.00 35 and Hpp=0.65-1.1 mT, RS signal was also simulated as a powder spectrum but with axi-symmetric spectrum characteristics. The spectrum parameters of RS were: g ⊥ =2.0018, g ‖ =1.9965, Hpp=0.335-0.4 mT. The amplitude of RS had a linear response to radiation dose with the regression equation as y=240.74x + 76 724 (R 2 =0.9947). The expectation of relative error of dose estimation was 0.13. Conclusions: EPR simulation method has improved somehow the accuracy and reliability of enamel EPR dose estimation. (authors)

  5. Biophysical dose measurement using electron paramagnetic resonance in rodent teeth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

    2003-01-01

    Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. However, there are situations that do not involve a human victim (e.g. tests for suspected environmental overexposures, measurements of doses to experimental animals in radiation biology research, or chronology of archaeological deposits). For such cases we have developed an EPR dosimetry technique making use of enamel of teeth extracted from mice. Tooth enamel from both previously irradiated and unirradiated mice was extracted and cleaned by processing in supersaturated KOH aqueous solution. Teeth from mice with no previous irradiation history exhibited a linear EPR response to the dose in the range from 0.8 to 5.5 Gy. The EPR dose reconstruction for a preliminarily irradiated batch resulted in the radiation dose of (1.4±0.2) Gy, which was in a good agreement with the estimated exposure of the teeth. The sensitivity of the EPR response of mouse enamel to gamma radiation was found to be half of that of human tooth enamel. The dosimetric EPR signal of mouse enamel is stable up at least to 42 days after exposure to radiation. Dose reconstruction was only possible with the enamel extracted from molars and premolars and could not be performed with incisors. Electron micrographs showed structural variations in the incisor enamel, possibly explaining the large interfering signal in the non-molar teeth

  6. Lanthanide-based laser-induced phosphorescence for spray diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Voort, D. D. van der, E-mail: d.d.v.d.voort@tue.nl; Water, W. van de; Kunnen, R. P. J.; Clercx, H. J. H.; Heijst, G. J. F. van [Applied Physics Department, Eindhoven University of Technology, 5612 AZ Eindhoven (Netherlands); Maes, N. C. J.; Sweep, A. M.; Dam, N. J. [Mechanical Engineering Department, Eindhoven University of Technology, 5612 AZ Eindhoven (Netherlands); Lamberts, T. [Institute of Theoretical Chemistry, University of Stuttgart, D-70569 Stuttgart (Germany)

    2016-03-15

    Laser-induced phosphorescence (LIP) is a relatively recent and versatile development for studying flow dynamics. This work investigates certain lanthanide-based molecular complexes for their use in LIP for high-speed sprays. Lanthanide complexes in solutions have been shown to possess long phosphorescence lifetimes (∼1-2 ms) and to emit light in the visible wavelength range. In particular, europium and terbium complexes are investigated using fluorescence/phosphorescence spectrometry, showing that europium-thenoyltrifluoracetone-trioctylphosphineoxide (Eu-TTA-TOPO) can be easily and efficiently excited using a standard frequency-tripled Nd:YAG laser. The emitted spectrum, with maximum intensity at a wavelength of 614 nm, is shown not to vary strongly with temperature (293-383 K). The decay constant of the phosphorescence, while independent of ambient pressure, decreases by approximately 12 μs/K between 323 and 373 K, with the base level of the decay constant dependent on the used solvent. The complex does not luminesce in the gas or solid state, meaning only the liquid phase is visualized, even in an evaporating spray. By using an internally excited spray containing the phosphorescent complex, the effect of vaporization is shown through the decrease in measured intensity over the length of the spray, together with droplet size measurements using interferometric particle imaging. This study shows that LIP, using the Eu-TTA-TOPO complex, can be used with different solvents, including diesel surrogates. Furthermore, it can be easily handled and used in sprays to investigate spray breakup and evaporation.

  7. High temperature vaporization/decomposition studies of lanthanide and actinide fluorides

    International Nuclear Information System (INIS)

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

    1987-01-01

    Binary fluorides of the lanthanide and actinide elements comprise a fundamental class of compounds. The authors' investigations of their basic high temperature vaporization and/or decomposition behavior are aimed at elucidating more fully the thermal properties of selected tri- and tetrafluorides and extending such investigations to fluorides which have not been studied previously. Depending on the particular system and the specific experimental conditions, the authors' measurements can provide such information as the enthalpy associated with a congruent vaporization process and/or the relative stabilities of fluorides containing a lanthanide/actinide element in different oxidation states. The authors are also studying the congruent vaporization of selected lanthanide trifluorides with particular emphasis on two areas. The first concerns the variation in the enthalpies of sublimation of the trifluorides across the lanthanide series. Although this variation is rather small (δ5 kcal where ΔH/sub subl/ is approximately 100 kcal), it is larger than observed for other lanthanide trihalides and is unusually irregular. To examine this reported variation more closely, they are attempting to measure relative vapor pressures/enthalpies of vaporization by studying mixtures of two or more lanthanide trifluorides by the technique discussed above

  8. Ternary complex formation of lanthanides and radiolanthanides with phosphate and serum proteins

    International Nuclear Information System (INIS)

    Neumaier, B.; Roesch, F.

    1999-01-01

    Radioyttrium was recently reported to form ternary complexes with phosphate and serum proteins in blood. In the present work it was investigated whether the trivalent radiolanthanides react in a chemically similar way. In systematic binding studies using gel filtration a ternary complex formation between different lanthanides, phosphate and serum proteins could be identified. The tendency to build a ternary compound of the type Ln III - phosphate - serum protein, however, is dependent on the ionic radii of the lanthanides. Whereas the light and transition lanthanides have a strong inclination to build a ternary complex, this tendency is weaker for the heavier ones. Taking into account the high content of phosphate in human blood, the corresponding ternary complexes of radiolanthanides represent an important transport form of these elements in blood. This finding may contribute to an understanding of the nuclear medical observation on the biodistribution of radiolanthanides. The heavy radiolanthanides can be classified as bone seeking metals, whereas the light and transition lanthanide elements accumulate mainly in the liver and the spleen. For the lighter radiolanthanides the corresponding ternary complexes thus represent an important transport form in blood. This physicochemical form of lanthanides mainly results in reticulo endothelial accumulation; on the other hand, the lower tendency of heavier lanthanides leads to preferential skeletal deposition. (orig.)

  9. Lanthanide fission product separation from the transuranics in the integral fast reactor fuel cycle demonstration

    International Nuclear Information System (INIS)

    Goff, K.M.; Mariani, R.D.; Benedict, R.W.; Ackerman, J.P.

    1993-01-01

    The Integral Fast Reactor (IFR) is an innovative reactor concept being developed by Argonne National Laboratory. This reactor uses liquid-metal cooling and metallic fuel. Its spent fuel will be reprocessed using a pyrochemical method employing molten salts and liquid metals in an electrofining operation. The lanthanide fission products are a concern during reprocessing because of heating and fuel performance issues, so they must be removed periodically from the system to lessen their impact. The actinides must first be removed form the system before the lanthanides are removed as a waste stream. This operation requires a relatively good lanthanide-actinide separation to minimize both the amount of transuranic material lost in the waste stream and the amount of lanthanides collected when the actinides are first removed. A computer code, PYRO, that models these operations using thermodynamic and empirical data was developed at Argonne and has been used to model the removal of the lanthanides from the electrorefiner after a normal operating campaign. Data from this model are presented. The results demonstrate that greater that 75% of the lanthanides can be separated from the actinides at the end of the first fuel reprocessing campaign using only the electrorefiner vessel

  10. Antiferromagnetic–paramagnetic state transition of NiO synthesized by pulsed laser deposition

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-01-01

    Full Text Available respectively from Raman spectroscopy study. These particle sizes are known be affected by substrate temperature during the deposition. Electron spin resonance (ESR) results demonstrated a strange antiferromagnetic to paramagnetic transition at a room...

  11. Electron paramagnetic resonance study on the ionizing radiation induced defects of the tooth enamel hydroxyapatite

    International Nuclear Information System (INIS)

    Oliveira, Liana Macedo de

    1995-01-01

    Hydroxyapatite is the main constituent of calcified tissues. Defects induced by ionizing radiations in this biomineral can present high stability and then, these are used as biological markers in radiological accidents, irradiated food identifying and geological and archaeological dating. In this work, paramagnetic centers induced on the enamel of the teeth by environmental ionizing radiation, are investigated by electron paramagnetic resonance (EPR). Decay thermal kinetic presents high complexity and shows the formation of different electron ligation energy centers and structures

  12. Dosimetry of ionizing radiations by Electron paramagnetic resonance; Dosimetria de radiaciones ionizantes por resonancia paramagnetica electronica

    Energy Technology Data Exchange (ETDEWEB)

    Azorin N, J [UAM-I, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  13. Two-frequency radiospectrometer for studying paramagnetics under a strong magnetic field

    International Nuclear Information System (INIS)

    Vertii, A.A.; Gudym, I.Y.; Ivanchenko, I.V.

    1994-01-01

    A two-frequency radiospectrometer for studying electron paramagnetic resonance in the 120-150-GHz band and nuclear magnetic resonance in the 180-200-MHz band is described. The spectrometer is used to measure the properties of paramagnetics by a double-resonance technique in a magnetic field of up to 5 T at a temperature ranging from 1.7 to 20 degrees K

  14. Electrically-detected electron paramagnetic resonance of point centers in 6H-SiC nanostructures

    Czech Academy of Sciences Publication Activity Database

    Bagraev, N.T.; Gets, D.S.; Kalabukhova, E.N.; Klyachkin, L.E.; Malyarenko, A.M.; Mashkov, V.A.; Savchenko, Dariia; Shanina, B.D.

    2014-01-01

    Roč. 48, č. 11 (2014), s. 1467-1480 ISSN 1063-7826 R&D Projects: GA MŠk(CZ) LM2011029 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : electron paramagnetic resonance * electrically- detected electron paramagnetic resonance * 6H -SiC nanostructures * nitrogen-vacancy defect * point defect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.739, year: 2014

  15. Paramagnetic moments in YBa2Cu3O7−δ nanocomposite films

    International Nuclear Information System (INIS)

    Dias, F.T.; Vieira, V.N.; Silva, D.L.; Albino Aguiar, J.; Valadão, D.R.B.; Obradors, X.; Puig, T.; Wolff-Fabris, F.; Kampert, E.

    2014-01-01

    Highlights: • The paramagnetic Meissner effect was observed in a nanocomposite YBaCuO thin film. • The paramagnetic moments in FC experiments were observed up to 10 T. • The paramagnetic Meissner effect increases when the magnetic field is increased. • Results may be explained based on the flux compression scenario and vortex pinning. • An apparent saturation tendency of the paramagnetic moments could be observed. - Abstract: We report on magnetization studies in YBa 2 Cu 3 O 7−δ thin films with dispersed Ba 2 YTaO 6 nanoparticles. The magnetization measurements were made using a superconducting quantum interference device (SQUID) and a vibrating sample magnetometer (VSM). Magnetic moments were measured as functions temperature using zero-field cooling (ZFC) and field-cooled (FC) prescriptions for magnetic fields up to 10 T applied parallel and perpendicular to the ab planes. A paramagnetic response related to the superconducting state was observed during the FC experiments. This effect, known as paramagnetic Meissner effect (PME), apparently increases when the magnetic field is increased. We discuss our PME results in terms of the strong pinning scenario modulated by Ba 2 YTaO 6 nanoparticles dispersed into the superconducting matrix

  16. Thermodynamic modelling of the extraction of nitrates of lanthanides by CMPO and by CMPO-like calixarene in concentrated nitric acid medium. Application in the optimization of the separation of lanthanides and actinides/lanthanides

    International Nuclear Information System (INIS)

    Belair, S.

    2003-01-01

    The separation minor actinides / lanthanides in nitric acid medium is as one of problems of separative chemistry the most delicate within the framework of the processes allowing the recovery of long life radioelements present in the solutions of fission products. Previous studies showed that CMPO-substituted calix[4]arenes presents a better affinity for actinides than for lanthanides. To optimize the operating conditions of separation and to take into account the degree of non-ideality for the concentrated nitric solutions, we adopted a thermodynamic approach. The methodology taken to determine the number and the stoichiometry of the complexes formed in organic phase base on MIKULIN-SERGIEVSKII's model used through a software of data processing of experimental extraction isotherms. These tools are exploited at first on an extraction system engaging the CMPO, extractant reagent of actinides and lanthanides in concentrated nitric medium. The modelling of the system Ln(NO 3 ) 3 -HNO 3 -H 2 O/CMPO comes to confirm the results of several studies. At the same time, they allow to establish working hypotheses aiming at limiting the investigations of our researches towards the most stable complexes formed between lanthanides and CMPO-like calixarene to which the same method is then applied. An analytical expression of the selectivity of separation by the calixarene is established to determine the parameters and physico-chemical variables on which it depends. So, the ratio of the constants of extraction and the value of the activity of water of the system fixes the selectivity of separation of 2 elements. The exploitation of this relation allows to preview the influence of a variation of the concentration of nitric acid. Experiments of extraction confirm these forecasts and inform about the affinity of the calixarene with respect to lanthanides elements and to the americium. (author)

  17. Radiation dosimetry in human bone using electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Breen, S.L.

    1995-01-01

    Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with a half-life of many years. The population of trapped unpaired electrons is proportional to the radiation dose administered to the bone and can be measured in excised bone samples using electron paramagnetic resonance (EPR). EPR spectra of synthetic hydroxyapatite, irradiated with Co-60, were obtained at room temperature and at 77 K. At room temperature, the radiation-induced signal, with a g-value of 2.001 ± 0.001 increased linearly with absorbed dose above a lower threshold of 3 Gy, up to doses of 200 Gy. In contrast with pure hydroxyapatite, EPR spectra of excised human bone showed a broad 'native' signal, due to the organic component of bone, which masks the dosimetrically important signal. This native signal is highly variable from sample to sample and precludes the use of EPR as an absolute dosimetry technique. However, after subtraction of the background signal, irradiated human bone showed a linear response with a lower limit of measurement similar to that of synthetic hydroxyapatite. Bone is an in vivo linear dosimeter which can be exploited to develop accurate estimates of the radiation dose delivered during systemic radiotherapy and teletherapy. However, improved sensitivity of the EPR dosimetry technique is necessary before it can be applied reliably in clinical situations. (author)

  18. Paramagnetic relaxation enhancements in NMR peptide-membrane interaction studies

    International Nuclear Information System (INIS)

    Kosol, S.

    2011-01-01

    Small membrane-bound proteins or peptides are involved in numerous essential biological processes, like cellular recognition, signaling, channel formation, and cytolysis. The secondary structure, orientation, mode of interaction and dynamics of these peptides can be as varied as their functions. Their localization in the membrane, the immersion depth, and their binding mode are factors critical to the function of these peptides. The atomic 3D solution structure of peptides bound to micelles can be determined by NMR spectroscopy. However, by employing paramagnetic relaxation enhancements (PREs) information on the complete topology of peptide bound to a micelle can be obtained. The antimicrobial peptide maximin H6, fst, a bacterial toxin, and the human peptide hormone ghrelin served as membrane-bound model peptides of similar sizes but strongly differing amino acid sequences. Their structures and binding behavior were determined and compared.The measured PREs provided suitable data for determining and distinguishing the different topologies of the investigated peptides bound to micelles. Maximin H6 and fst fold into α-helices upon insertion into a membrane, whereas the unstructured ghrelin is freely mobile in solution and interacts only via a covalently bound octanoyl group with the lipids. Maximin H6 is oriented parallel to the membrane surface, enabling the peptide to aggregate at the membrane water interface. Fst binds in transmembrane orientation with a protruding intrinsically disordered region near the C-terminus. Aside from determining the orientation of the bound peptides from the PREs, the moieties critical for membrane binding could be mapped in ghrelin. If suitable relaxation-edited spectra are acquired, the complete orientation and immersion depth of a peptide bound to a micelle can readily be obtained. (author) [de

  19. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.

    2003-01-01

    This thesis deals with the advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency, and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post-process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma exposures as low as 80±30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in 100 mGy ranges can be easily reconstructed in teeth that were previously thought useless for EPR dosimetry. Also, the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K.N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons

  20. Electron paramagnetic resonance detection of carotenoid triplet states

    International Nuclear Information System (INIS)

    Frank, H.A.; Bolt, J.D.; deCosta, S.M.; Sauer, K.

    1980-01-01

    Triplet states of carotenoids have been detected by X-band electron paramagnetic resonance (EPR) and are reported here for the first time. The systems in which carotenoid triplets are observed include cells of photosynthetic bacteria, isolated bacteriochlorophyll-protein complexes, and detergent micelles which contain β-carotene. It is well known that if electron transfer is blocked following the initial acceptor in the bacterial photochemical reaction center, back reaction of the primary radical pair produces a bacteriochlorophyll dimer triplet. Previous optical studies have shown that in reaction centers containing carotenoids the bacteriochlorophyll dimer triplet sensitizes the carotenoid triplet. We have observed this carotenoid triplet state by EPR in reaction centers of Rhodopseudomonas sphaeroides, strain 2.4.1 (wild type), which contain the carotenoid spheroidene. The zero-field splitting parameters of the triplet spectrum are /D/ = 0.0290 +- 0.0005 cm -1 and /E/ = 0.0044 +-0.0006 cm -1 , in contrast with the parameters of the bacteriochlorophyll dimer triplet, which are /D/ = 0.0189 +- 0.0004 cm -1 and /E/ = 0.0032 +- 0.004 cm -1 . Bacteriochlorophyll in a light harvesting protein complex from Rps. sphaeroides, wild type, also sensitizes carotenoid triplet formation. In whole cells the EPR spectra vary with temperature between 100 and 10 K. Carotenoid triplets also have been observed by EPR in whole cells of Rps. sphaeroides and cells of Rhodospirillum rubrum which contain the carotenoid spirilloxanthin. Attempts to observe the triplet state EPR spectrum of β-carotene in numerous organic solvents failed. However, in nonionic detergent micelles and in phospholipid bilayer vesicles β-carotene gives a triplet state spectrum with /D/ = 0.0333 +- 0.0010 cm -1 and /E/ = 0.0037 +- 0.0010 cm -1 . 6 figures, 1 table

  1. A Novel Paramagnetic Substrate for Detecting Myeloperoxidase Activity in Vivo

    Directory of Open Access Journals (Sweden)

    Mohammed S. Shazeeb

    2012-09-01

    Full Text Available Bis-phenylamides and bis-hydroxyindolamides of diethylenetriaminepentaacetic acid-gadolinium (DTPA(Gd are paramagnetic reducing substrates of peroxidases that enable molecular imaging of peroxidase activity in vivo. Specifically, gadolinium chelates of bis-5-hydroxytryptamide-DTPA (bis-5HT-DTPA(Gd have been used to image localized inflammation in animal models by detecting neutrophil-derived myeloperoxidase (MPO activity at the inflammation site. However, in other preclinical disease models, bis-5HT-DTPA(Gd presents technical challenges due to its limited solubility in vivo. Here we report a novel MPO-sensing probe obtained by replacing the reducing substrate serotonin (5-HT with 5-hydroxytryptophan (HTrp. Characterization of the resulting probe (bis-HTrp-DTPA(Gd in vitro using nuclear magnetic resonance spectroscopy and enzyme kinetic analysis showed that bis-HTrp-DTPA(Gd (1 improves solubility in water; (2 acts as a substrate for both horseradish peroxidase and MPO enzymes; (3 induces cross-linking of proteins in the presence of MPO; (4 produces oxidation products, which bind to plasma proteins; and (5 unlike bis-5HT-DTPA(Gd, does not follow first-order reaction kinetics. In vivo magnetic resonance imaging (MR! in mice demonstrated that bis-HTrp-DTPA(Gd was retained for up to 5 days in MPO-containing sites and cleared faster than bis-5HT-DTPA(Gd from MPO-negative sites. Bis-HTrp-DTPA(Gd should offer improvements for MR! of MPO-mediated inflammation in vivo, especially in high-field MR!, which requires a higher dose of contrast agent.

  2. A novel paramagnetic substrate for detecting myeloperoxidase activity in vivo.

    Science.gov (United States)

    Shazeeb, Mohammed S; Xie, Yang; Gupta, Suresh; Bogdanov, Alexei A

    2012-01-01

    Bis-phenylamides and bis-hydroxyindolamides of diethylenetriaminepentaacetic acid-gadolinium (DTPA(Gd)) are paramagnetic reducing substrates of peroxidases that enable molecular imaging of peroxidase activity in vivo. Specifically, gadolinium chelates of bis-5-hydroxytryptamide-DTPA (bis-5HT-DTPA(Gd)) have been used to image localized inflammation in animal models by detecting neutrophil-derived myeloperoxidase (MPO) activity at the inflammation site. However, in other preclinical disease models, bis-5HT-DTPA(Gd) presents technical challenges due to its limited solubility in vivo. Here we report a novel MPO-sensing probe obtained by replacing the reducing substrate serotonin (5-HT) with 5-hydroxytryptophan (HTrp). Characterization of the resulting probe (bis-HTrp-DTPA(Gd)) in vitro using nuclear magnetic resonance spectroscopy and enzyme kinetic analysis showed that bis-HTrp-DTPA(Gd) (1) improves solubility in water; (2) acts as a substrate for both horseradish peroxidase and MPO enzymes; (3) induces cross-linking of proteins in the presence of MPO; (4) produces oxidation products, which bind to plasma proteins; and (5) unlike bis-5HT-DTPA(Gd), does not follow first-order reaction kinetics. In vivo magnetic resonance imaging (MRI) in mice demonstrated that bis-HTrp-DTPA(Gd) was retained for up to 5 days in MPO-containing sites and cleared faster than bis-5HT-DTPA(Gd) from MPO-negative sites. Bis-HTrp-DTPA(Gd) should offer improvements for MRI of MPO-mediated inflammation in vivo, especially in high-field MRI, which requires a higher dose of contrast agent.

  3. Rapid separation of lanthanides and actinides on small particle based reverse phase supports

    Energy Technology Data Exchange (ETDEWEB)

    Datta, A.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2010-07-01

    This paper presents the results on the use of short columns (3-5 cm long) with small particle size (1.8 {mu}m) for high performance liquid chromatographic separation of individual lanthanides and uranium from plutonium as well as uranium from thorium to achieve rapid separations i.e. separation time as short as 3.6 min for individual lanthanides, 1 min for thorium-uranium and 4.2 min for uranium from plutonium. These advantages can be exploited to significantly reduce analysis time, liquid waste generation as well as dose to operator when radioactive samples are analysed e.g. burn-up determination. In the present work, a dynamic ion-exchange chromatographic separation technique was employed using camphor-10-sulfonic acid (CSA) as the ion-pairing reagent and {alpha}-hydroxy isobutyric acid ({alpha}-HIBA) as the complexing reagent for the isolation of individual lanthanides as well as the separation of uranium from thorium. Uranium was separated from Pu(III) as well as Pu(IV) by reverse phase HPLC technique. The reverse phase HPLC was also investigated for the isolation and quantitative determination of uranium from thorium as well as lanthanide group from uranium. The dynamic ion-exchange technique using small particle support was demonstrated for measuring the concentrations of lanthanide fission products such as La, Ce, Pr, Nd and Sm in the dissolver solution of fast reactor fuel. Similarly, the assay of uranium in the dissolver solution of fast reactor was carried out using reverse phase HPLC technique. The rapid separation technique using reverse phase HPLC was also demonstrated for separation of lanthanides as a group from uranium matrix; samples of LiCl-KCl eutectic salt containing chlorides of lanthanides in uranium matrix (typically 1: 2000) were analysed. (orig.)

  4. Thermodynamic modelling of the extraction of nitrates of lanthanides by CMPO and by CMPO-like calixarene in concentrated nitric acid medium. Application in the optimization of the separation of lanthanides and actinides/lanthanides; Modelisation thermodynamique de l'extraction de nitrates de lanthanides par le CMPO et par un calixarene-CMPO en milieu acide nitrique concentre. Application a l'optimisation de la separation des lanthanides et des actinides/lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Belair, S

    2003-07-01

    The separation minor actinides / lanthanides in nitric acid medium is as one of problems of separative chemistry the most delicate within the framework of the processes allowing the recovery of long life radioelements present in the solutions of fission products. Previous studies showed that CMPO-substituted calix[4]arenes presents a better affinity for actinides than for lanthanides. To optimize the operating conditions of separation and to take into account the degree of non-ideality for the concentrated nitric solutions, we adopted a thermodynamic approach. The methodology taken to determine the number and the stoichiometry of the complexes formed in organic phase base on MIKULIN-SERGIEVSKII's model used through a software of data processing of experimental extraction isotherms. These tools are exploited at first on an extraction system engaging the CMPO, extractant reagent of actinides and lanthanides in concentrated nitric medium. The modelling of the system Ln(NO{sub 3}){sub 3}-HNO{sub 3}-H{sub 2}O/CMPO comes to confirm the results of several studies. At the same time, they allow to establish working hypotheses aiming at limiting the investigations of our researches towards the most stable complexes formed between lanthanides and CMPO-like calixarene to which the same method is then applied. An analytical expression of the selectivity of separation by the calixarene is established to determine the parameters and physico-chemical variables on which it depends. So, the ratio of the constants of extraction and the value of the activity of water of the system fixes the selectivity of separation of 2 elements. The exploitation of this relation allows to preview the influence of a variation of the concentration of nitric acid. Experiments of extraction confirm these forecasts and inform about the affinity of the calixarene with respect to lanthanides elements and to the americium. (author)

  5. 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 SmII/SmIII and YbII/YbIII 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

  6. Electron paramagnetic resonance study of Ce doped partially stabilized ZrO2 crystals

    Directory of Open Access Journals (Sweden)

    Mikhail А. Borik

    2017-09-01

    Full Text Available ZrO2 (PSZ solid solutions crystals stabilized with yttrium and cerium oxides have been studied using electron paramagnetic resonance (EPR in the X and Q ranges. Zr3+ have been observed centers in the as-annealed ZrO2 crystals stabilized only by yttrium oxide (2.8 mol% Y2O3. Another type of paramagnetic-O-centers appear as a result of CeO2 addition to ZrO2 crystals along with yttrium oxide. To estimate the concentration of Ce3+ ions in PZS crystals, we recorded the EPR spectra in the presence of a reference at 7 K. Paramagnetic Ce3+ ions have been identified and their relative amount in the PSZ crystals before and after high-temperature heat treatment has been assessed. Annealing in air leads decreases the concentration of Ce3+ ions for all the test compositions and changes the color of the crystals from red to white. After annealing of the sample 2.0Y0.8Ce3Zr, the amount of paramagnetic Ce3+ ions decreased approximately twofold. Paramagnetic centers from Ce3+ have not been detected in the specimen with a low cerium content of 0.1 mol% after annealing which indicates the complete transition of Ce3+ to the Ce4+ state. We show that the forming cerium paramagnetic centers are bound by strong exchange interactions. No angular dependence of the EPR lines of the paramagnetic Ce3+ cations on the applied external magnetic field has been observed. Probable origin of the absence of angular dependence is that the impurity rare-earth ions are located close to one another, forming impurity clusters with an effective spin of Seff=1/2.

  7. Calorimetric approach of lanthanides (3) complexation and extraction by malonamides; Approche calorimetrique de la complexation et de l'extraction des lanthanides (3) par les malonamides

    Energy Technology Data Exchange (ETDEWEB)

    Flandin, J.L

    2001-07-01

    In the field of long lived radionuclides separation, diamides are interesting extractants because of their ability to co-extract trivalent lanthanides and actinides, which is a preliminary and essential step in high level radioactive waste reprocessing. The research carried out contributes to a better understanding of the mechanisms and the aim is the determination of thermodynamics properties ({delta}{sub r}G, {delta}{sub r}H et {delta}{sub r}S) related to the complexation and the extraction of lanthanides(III) by malonamides. The first part of the document deals with the complexation of lanthanides(III) by an hydrosoluble diamide. The experimental results obtained by UV-visible spectrometry, TRLIF, NMR and microcalorimetric titration proved that lanthanides(III)-TEMA interactions in aqueous medium are very weak and that the complexation reaction is endothermic. The TEMA ligand still stays in the second coordination sphere of coordination of the lanthanide ion. The second part of this study focuses on the extraction of neodymium(III) nitrate by a lipophilic diamide which is an exothermic reaction. The influence of the composition of aqueous and organic phases on the thermodynamics properties {delta}{sub r}G et {delta}{sub r}H has been studied by microcalorimetric titration. The most influent parameter is the total concentration in extractant. As a consequence, thermodynamic values are very dependent on the organic phase organisation before and alter extraction. At the same time, this study showed the interest of the calorimetric approach for the analysis of basic reactions like diamide dilution and their organisation as oligomeric aggregates. (author)

  8. 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.

  9. The commercial production of compounds of the lanthanides and yttrium as CRT phosphor precursors

    International Nuclear Information System (INIS)

    Kilbourn, B.T.

    1987-01-01

    The consumer acceptance of color television at the start of the 60's was triggered by the phosphor industry's discovery and production of a satisfactory red phosphor using the element europium. This element, in the middle of the lanthanide series, had until that time been an academic curiosity, prepared only in gram quantities for research. The large-scale production by the lanthanide industry, in order to meet the demand for commercial quantities of high purity europium oxide, required the introduction of new technology. Lanthanide elements other than europium, such as cerium and terbium, are also needed as the active ions for many phosphors. In addition, the inert host lattice for those emitting ions can be provided by compounds of yttrium, the element above the lanthanides in the periodic table, with comparable properties. The lanthanide industry has developed processes to produce compounds of such elements in the required quantities and purities. For commercial separation of these elements a technology known as counter-current liquid-liquid extraction has been developed. This technique, commonly called solvent extraction, is illustrated and described. The initial ore preparation steps, together with the final high purity oxide production is also mentioned

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Efficiency of crystalline laser materials based on lanthanides

    International Nuclear Information System (INIS)

    Synek, M.

    1990-01-01

    Lanthanide-based laser-crystal efficiency has been investigated, using the laser-active ions Dy 2+ and Nd 3+ as significant illustrations. Authors' calculations, and various approaches by other authors, are reviewed. In specific examples of treatment, the analytical self-consistent field(SCF) expansion method has been used to calculate accurate ab initio wave functions and energy levels for a number of excited states of Nd 3+ and Dy 2+ , which were investigated for the first time. General group-theoretical principles were considered and the formulae for crystal-field parameters were obtained. The Racah quantum numbers were included in these calculations, in fact showing sizeable energy effects. Oscillator strengths, calculated from the SCF wave functions, revealed which orbitals can be neglected without influencing the transition probability at the fourth significant figure. The relationship to the spectral character of the pumping device was considered. The efficiency parameters (mechanical, economic, and energetic) have to be considered as supplementing the related threshold energy parameter. It would be conceivable to predict the applicability of competing laser systems to a specific task, based on integrated energy pictures. (author). 32 refs., 2 tabs

  15. Lattice disorder in strongly correlated lanthanide and actinide intermetallics

    International Nuclear Information System (INIS)

    Booth, C.H.; Bauer, E.D.; Maple, M.B.; Lawrence, J.M.; Kwei, G.H.; Sarrao, J.L.

    2001-01-01

    Lanthanide and actinide intermetallic compounds display a wide range of correlated-electron behavior, including ferromagnetism, antiferromagnetism, nonmagnetic (Kondo) ground states, and so-called 'non-Fermi liquid' (NFL) behavior. The interaction between f electrons and the conduction band is a dominant factor in determining the ground state of a given system. However, lattice disorder can create a distribution of interactions, generating unusual physical properties. These properties may include NFL behavior in many materials. In addition, lattice disorder can cause deviations from standard Kondo behavior that is less severe than NFL behavior. A review of the lattice disorder mechanism within a tight-binding model is presented, along with measurements of the YbBCu 4 and UPd x Cu 5-x systems, demonstrating the applicability of the model. These measurements indicate that while the YbBCu 4 system appears to be well ordered, both site interchange and continuous bond-length disorder occur in the UPd x Cu 5-x series. Nevertheless, the measured bond-length disorder in UPdCu 4 does not appear to be enough to explain the NFL properties simply with the Kondo disorder model. (au)

  16. Lanthanide ions as absorption spectral probes in biochemical reactions

    International Nuclear Information System (INIS)

    Misra, S.N.

    1989-01-01

    The interactions of adenine, adenosine, adenosine 5'-monophosphate, 5'-diphosphate and 5'-triphosphate with Pr(III) and Nd(III) in different stoichiometries and at varying pH levels have been investigated by electronic spectral studies. The intra 4f-4f transitions yield sharp bands which were analysed individually by Gaussian curve analysis. The energy interaction (Fsup(k),Esup(k)) spin orbit interaction (ζ4f), bonding(b), nephelauxetic (β,δ) and intensity parameters (Tsub(τ.P)) have been computed on HP-1000/45 computer using regression analyses refined by least square fit. The nature of bonding, coordination environment, outer and inner sphere coordination have been interpreted in terms of the magnitude of these parameters as compared to the lanthanide free ion. In order to supplicate the solution studies the crystalline compounds of AMP, ADP and ATP with Pr(III) and Nd(III) have been isolated and characterized by IR, 1 H and 31 P NMR studies. The infrared spectral data indicated weak interaction with the imidazole nitrogen of adenine moiety and bidentate attachment of oxygen. (author). 10 refs

  17. Photo-reactive charge trapping memory based on lanthanide complex

    Science.gov (United States)

    Zhuang, Jiaqing; Lo, Wai-Sum; Zhou, Li; Sun, Qi-Jun; Chan, Chi-Fai; Zhou, Ye; Han, Su-Ting; Yan, Yan; Wong, Wing-Tak; Wong, Ka-Leung; Roy, V. A. L.

    2015-10-01

    Traditional utilization of photo-induced excitons is popularly but restricted in the fields of photovoltaic devices as well as photodetectors, and efforts on broadening its function have always been attempted. However, rare reports are available on organic field effect transistor (OFET) memory employing photo-induced charges. Here, we demonstrate an OFET memory containing a novel organic lanthanide complex Eu(tta)3ppta (Eu(tta)3 = Europium(III) thenoyltrifluoroacetonate, ppta = 2-phenyl-4,6-bis(pyrazol-1-yl)-1,3,5-triazine), in which the photo-induced charges can be successfully trapped and detrapped. The luminescent complex emits intense red emission upon ultraviolet (UV) light excitation and serves as a trapping element of holes injected from the pentacene semiconductor layer. Memory window can be significantly enlarged by light-assisted programming and erasing procedures, during which the photo-induced excitons in the semiconductor layer are separated by voltage bias. The enhancement of memory window is attributed to the increasing number of photo-induced excitons by the UV light. The charges are stored in this luminescent complex for at least 104 s after withdrawing voltage bias. The present study on photo-assisted novel memory may motivate the research on a new type of light tunable charge trapping photo-reactive memory devices.

  18. Dissolution of lanthanide alumino-silicate oxynitride glasses

    Science.gov (United States)

    Bois, L.; Barré, N.; Guillopé, S.; Guittet, M. J.; Gautier-Soyer, M.; Duraud, J. P.; Trocellier, P.; Verdier, P.; Laurent, Y.

    2000-01-01

    The aqueous corrosion behavior of lanthanide aluminosilicate glasses has been studied under static conditions ( T=96°C, duration=1 and 3 months, glass surface area/leachate volume, S/ V=0.3 cm -1) by means of solution and solid analyses. It was found that these glasses exhibit a high chemical durability. The influence of yttrium, magnesium and nitrogen, which are supposed to improve the mechanical properties, on the chemical durability, has been investigated. After a one-month experiment, lanthanum and yttrium releases were found to be about 10 -7 mol l -1, while silicon and aluminum releases were about 10 -5 mol l -1. Yttrium seems to improve the chemical durability. The presence of nitrogen does not seem to modify the glass constituents releases, but seems to improve the surface state of the altered glass. XPS experiments reveal that lanthanum and yttrium are more concentrated near the surface (20-30 Å) of the glass after the leaching test.

  19. Studies on mixed ligand complexes of lanthanide (III) ions

    International Nuclear Information System (INIS)

    Rajendran, G.; Usha Devi, K.G.

    2002-01-01

    As part of our research programme, we have prepared and characterized a few nitrato, thiocyanato and perchlorato complexes of lanthanide(III) ions with ligands, viz., a Schiff base derived from p-anisidine and vanillin and diphenyl sulphoxide. The complexes were characterized by the measurement of electrical conductances and magnetic susceptibilities, molecular mass and metal percentage and spectral analysis. The thermal decompositions were studied by TG and DTG techniques. The thiocyanato complexes were prepared by substitution method from nitrato complexes. p-Anisidine-vanillin (HDDA) and diphenyl sulphoxide (DPSO) are coordinated to the metal ion in unidentate fashion. All the anions were involved in coordination in these complexes. Thus they were found to have non- electrolytic behaviour with composition [Ln(HDDA) 2 (DPSO)X 3 ] where X = NO 3 ) or SCN perchlorato complexes were prepared from metal perchlorate as done in the case of nitrato complexes. They were found to have electrical conductance which corresponds to 1 : 1 electrolyte. Hence one of the perchlorate ions is outside the coordination sphere. The composition of this complex is found to be [Ln(HDDA) 3 (DPSO)(ClO 4 ) 2 ]ClO 4 . (author)

  20. Lanthanide complexes of 2-aminoacetophenone and 2-acetylaminoacetophenone 2-thenoylhydrazone

    International Nuclear Information System (INIS)

    Singh, Praveen K.; Singh, B.

    1998-01-01

    The reaction of lanthanide chlorides with 2-aminoacetophenone-2-thenoyl- hydrazone and 2-acetylaminoacetophenone-2-thenoylhydrazone yield complexes of the type [Ln(aath) 2 Cl 2 (H 2 )O]Cl and [Ln(acaath) 2 Cl 2 ]Cl. These complexes have been characterized by molar conductance, magnetic susceptibility, TGA, DTA and various spectroscopic techniques such as mass, IR, NMR, UV - visible and emission spectra. Mass spectral data indicate the aath complexes to be monomeric. Thermal stability of the complexes and presence of one water molecule in aath complex is indicated by TGA and DTA studies. Electronic spectra of Pr(III) and Nd(III) complexes show the coordination number to be nine and eight around the metal ions in the aath and acaath complexes, respectively. This has also been inferred from the spectral features of the hypersensitive transition in the Nd(III) complexes. The lowering in coordination number from aath to acaath complexes may be attributed to increase in chelate ring size and/or steric/inductive effect of methyl group. Emission spectral studies of the [Eu(aath) 2 Cl 2 (H 2 O)]Cl and [Eu(acaath) 2 Cl 2 ]Cl suggest tricapped trigonal prismatic (D 3h ) and square antiprismatic (D 4d ) geometry, respectively. (author)

  1. PARAssign-paramagnetic NMR assignments of protein nuclei on the basis of pseudocontact shifts

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Simon P., E-mail: skinnersp@chem.leidenuniv.nl [Leiden University, Gorlaeus Laboratories, Leiden Institute of Chemistry (Netherlands); Moshev, Mois, E-mail: mois@monomon.me [Leiden University, Leiden Institute of Advanced Computer Science (Netherlands); Hass, Mathias A. S., E-mail: hassmas@chem.leidenuniv.nl; Ubbink, Marcellus, E-mail: m.ubbink@chem.leidenuniv.nl [Leiden University, Gorlaeus Laboratories, Leiden Institute of Chemistry (Netherlands)

    2013-04-15

    The use of paramagnetic NMR data for the refinement of structures of proteins and protein complexes is widespread. However, the power of paramagnetism for protein assignment has not yet been fully exploited. PARAssign is software that uses pseudocontact shift data derived from several paramagnetic centers attached to the protein to obtain amide and methyl assignments. The ability of PARAssign to perform assignment when the positions of the paramagnetic centers are known and unknown is demonstrated. PARAssign has been tested using synthetic data for methyl assignment of a 47 kDa protein, and using both synthetic and experimental data for amide assignment of a 14 kDa protein. The complex fitting space involved in such an assignment procedure necessitates that good starting conditions are found, both regarding placement and strength of paramagnetic centers. These starting conditions are obtained through automated tensor placement and user-defined tensor parameters. The results presented herein demonstrate that PARAssign is able to successfully perform resonance assignment in large systems with a high degree of reliability. This software provides a method for obtaining the assignments of large systems, which may previously have been unassignable, by using 2D NMR spectral data and a known protein structure.

  2. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  3. About kinetics of paramagnetic radiation malformations in beryllium ceramics; O kinetike nakopleniya paramagnitnykh radiatsionnykh defectov v berillievykh keramikakh

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, A I; Ryabinkin, Yu A; Zashkvara, O V; Bitenbaev, M I [Fiziko-tekhniucheskij Inst. Ministerstva Nauki i Vysshego Obrazovaniya Respubliki Kazakhstan, Almaty (Kazakhstan); Petukhov, Yu V [Inst. Atomnoj Ehnergii Natsional' nogo Yadernogo Tsentra Respubliki Kazakhstan, Almaty (Kazakhstan)

    1999-07-01

    This paper [1] specifies that {gamma}-radiation of the beryllium-oxide-based ceramics results in development of paramagnetic radiation malformations emerging the ESR spectrum in form of doublet with the splitting rate of oestrasid {delta}{approx}1.6 and g-factor of 2.008. This report presents evaluation outcomes of dependence of paramagnetic radiation malformations concentration in beryllium ceramics on gamma-radiation dose ({sup 60}Co) within the range of 0-100 Mrad. Total paramagnetic parameters of beryllium ceramics in the range 0-100 Mrad of gamma-radiation dose varied slightly, and were specified by the first type of paramagnetic radiation malformations.

  4. Faraday effect in γ-Dy2S3 and c-Dy2O3 paramagnetic crystals

    International Nuclear Information System (INIS)

    Shelykh, A.I.

    1987-01-01

    Studies of spectral and temperature dependences of Faraday effect in γ-Dy 2 S 3 and C-Dy 2 O 3 paramagnetic crystals are conducted. Paramagnetism of these crystals is brought about by Dy 3+ ions. Estimation of the effect of such factors as the value of paramagnetic ion concentration, width of the forbidden band, crystallochemical composition on magnetooptical effect in the considered compounds of dysprosium is carried out on the basis of the obtained experimental data and theoretical analysis. It is shown, that the Faraday effect in the considered compounds of dysprosium as well as the value of paramagnetic moment may be regarded rather accurately in free ion approximation

  5. Extended lanthanide-transition metal arrays with cyanide bridges: syntheses, structures, and catalytic applications

    International Nuclear Information System (INIS)

    Liu Shengming; Poplaukhin, Pavel; Ding Errun; Plecnik, Christine E.; Chen Xuenian; Keane, Mark A.; Shore, Sheldon G.

    2006-01-01

    Systematic synthetic procedures produced several different structural types of extended lanthanide-transition metal (group 10) complexes with cyanide bridges. Of these, one-dimensional ladder arrays containing a Yb-Pd combination have been converted to bimetallic heterogeneous catalysts on an oxide (SiO 2 ) surface that is more effective than supported Pd alone. Two lanthanide-Cu(I) complexes have been prepared. One type, an inclusion complex consists of lanthanide(III) cations encapsulated in the pockets of a three-dimensional anionic array that contains Cu(I)-CN-Cu(I) bridges. The second type, an extended layer complex, consists of joined five-membered rings in a 'tile-like' pattern with Ln-CN-Cu and Cu-CN-Cu bridges

  6. Separation of thorium from lanthanides by solvent extraction with ionizable crown ethers

    International Nuclear Information System (INIS)

    Du, H.S.; Wood, D.J.; Elshani, Sadik; Wai, C.M.

    1993-01-01

    Thorium and the lanthanides are extracted by α-(sym-dibenzo-16-crown-5-oxy)acetic acid and its analogues in different pH ranges. At pH 4.5, Th is quantitatively extracted by the crown ether carboxylic acids into chloroform whereas the extraction of the lanthanides is negligible. Separation of Th from the lanthanides can be achieved by solvent extraction under this condition. The extraction does not require specific counteranions and is reversible with respect to pH. Trace amounts of Th in water can be quantitatively recovered using this extraction system for neutron activation analysis. The nature of the extracted Th complex and the mechanism of extraction are discussed. (author)

  7. Separation of thorium from lanthanides by solvent extraction with ionizable crown ethers.

    Science.gov (United States)

    Du, H S; Wood, D J; Elshani, S; Wai, C M

    1993-02-01

    Thorium and the lanthanides are extracted by alpha-(sym-dibenzo-16-crown-5-oxy)acetic acid and its analogues in different pH ranges. At pH 4.5, Th is quantitatively extracted by the crown ether carboxylic acids into chloroform whereas the extraction of the lanthanides is negligible. Separation of Th from the lanthanides can be achieved by solvent extraction under this condition. The extraction does not require specific counteranions and is reversible with respect to pH. Trace amounts of Th in water can be quantitatively recovered using this extraction system for neutron activation analysis. The nature of the extracted Th complex and the mechanism of extraction are discussed.

  8. Effect of the Lithium Oxide Concentration on a Reduction of Lanthanide Oxides

    International Nuclear Information System (INIS)

    Choi, In-Kyu; Jeong, Myeong-Soo; Do, Jae-Bum; Seo, Chung-Seok

    2007-01-01

    The pyrochemical reduction process of spent oxide fuel is one of the options to handle spent PWR fuels in Korea. After spent oxide fuel is converted to a metallic form, fission products will be removed from the resultant uranium and higher actinide metals by an electrorefining process. The chemical behaviors of lanthanide oxides during the pyrochemical process has been extensively studied. It was also reported that about 30 to 50% of several lanthanide oxides were reduced to corresponding metals by an electrolytic reduction process having 1 wt% of a lithium oxide concentration. Korea Atomic Energy Research Institute (KAERI), however, has been used 3 wt% of lithium oxide to increase the applied current of the electrolytic reduction process. Though it was reported that U 3 O 8 was reduced to uranium metal having a high reduction yield at 3 wt% of the Li 2 O concentration, the effect of the lithium oxide concentration on the reduction of lanthanide oxides has not been clarified

  9. The Role of Chromohalobacter on Transport of Lanthanides and Cesium in the Dolomite Mineral System

    Energy Technology Data Exchange (ETDEWEB)

    Zengotita, Frances [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Emerson, Hilary Palmer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Wayne State Univ., Detroit, MI (United States); Swanson, Juliet S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reed, Donald T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-12-01

    The chemical behavior of actinide series elements and fission products is a concern for the Waste Isolation Pilot Plant repository due to their uncertain mobility in the subsurface salt formation. In this work, we are observing the behavior of the halophilic bacterium, Chromohalobacter, and its effect on the mobility of lanthanides and cesium in the presence of dolomite. Batch and minicolumn experiments were conducted with Cs+ and lanthanides (Nd3+, Eu3+) to quantify potential transport with bacteria. Preliminary results show that Cs does not interact strongly with dolomite or Chromohalobacter, while the lanthanides can interact strongly with both minerals and bacteria depending on which the Ln contacts first.

  10. Molecular design of highly efficient extractants for separation of lanthanides and actinides by computational chemistry

    International Nuclear Information System (INIS)

    Uezu, Kazuya; Yamagawa, Jun-ichiro; Goto, Masahiro

    2006-01-01

    Novel organophosphorus extractants, which have two functional moieties in the molecular structure, were developed for the recycle system of transuranium elements using liquid-liquid extraction. The synthesized extractants showed extremely high extractability to lanthanides elements compared to those of commercially available extractants. The results of extraction equilibrium suggested that the structural effect of extractants is one of the key factors to enhance the selectivity and extractability in lanthanides extractions. Furthermore, molecular modeling was carried out to evaluate the extraction properties for extraction of lanthanides by the synthesized extractants. Molecular modeling was shown to be very useful for designing new extractants. The new concept to connect some functional moieties with a spacer is very useful and is a promising method to develop novel extractants for treatment of nuclear fuel. (author)

  11. 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

  12. A generic biokinetic model for predicting the behaviour of the lanthanide elements in the human body

    International Nuclear Information System (INIS)

    Taylor, D.M.; Leggett, R.W.

    2003-01-01

    Information on the biokinetics of the 15 elements of the lanthanide series, 57 La to 71 Lu, is too sparse to permit individual development of meaningful biokinetic models to describe the behaviour of each of the elements in humans. The lanthanides show a regular gradation in chemical properties across the series, and animal studies indicate that this is reflected in regular differences in their deposition in tissues such as the liver and skeleton. These regular differences in chemical and biological behaviour have been utilised to construct a generic lanthanide biokinetic model and to define element-specific parameters for each element in the series. This report describes the use of the available biokinetic data for humans and animals to derive the parameters for each of the elements. (author)

  13. 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.

  14. NMR-based Enantiodifferentiation of Chiral trans-2-Phenylcyclopropane Derivatives Using a Chiral Lanthanide Shift Reagent

    International Nuclear Information System (INIS)

    Cho, Nam Sook; Kim, Hyun Sook; Song, Mi Sook

    2011-01-01

    In contrast with optical methods, there is no need to characterize the pure enantiomers. Instead, the NMR method makes use of chiral reagents that convert a mixture of enantiomers into a mixture of diastereomeric complexes. Integration of the resulting NMR spectra yields a direct measurement of enantiomeric purity as long as there is a sufficiently large difference between the chemical shifts of the two diastereoisomeric complexes to produce baseline-resolved peaks. Absolute enantiomeric configurations can also be determined using this method. Chiral lanthanide shift reagents have been used since the 1970s to form addition complexes with various compounds through interactions with electron donor sites. Lanthanide-induced, pseudo-contact shifts (LIS) are a function of the distance, r, between the nuclei under observation and the lanthanide center, and the angle, θ, between the line connecting the metal ion with the observed nucleus and the line representing the CLSR magnetic axis

  15. Average electronegativity, electronic polarizability and optical basicity of lanthanide oxides for different coordination numbers

    International Nuclear Information System (INIS)

    Zhao Xinyu; Wang Xiaoli; Lin Hai; Wang Zhiqiang

    2008-01-01

    On the basis of new electronegativity values, electronic polarizability and optical basicity of lanthanide oxides are calculated from the concept of average electronegativity given by Asokamani and Manjula. The estimated values are in close agreement with our previous conclusion. Particularly, we attempt to obtain new data of electronic polarizability and optical basicity of lanthanide sesquioxides for different coordination numbers (6-12). The present investigation suggests that both electronic polarizability and optical basicity increase gradually with increasing coordination number. We also looked for another double peak effect, that is, electronic polarizability and optical basicity of trivalent lanthanide oxides show a gradual decrease and then an abrupt increase at the Europia and Ytterbia. Furthermore, close correlations are investigated among average electronegativity, optical basicity, electronic polarizability and coordination number in this paper

  16. 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.

  17. In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence

    Directory of Open Access Journals (Sweden)

    Ribot EJ

    2014-04-01

    Full Text Available Emeline J Ribot,1 Jeffrey M Gaudet,1,2 Yuhua Chen,1 Kyle M Gilbert,1 Paula J Foster1,2 1Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada; 2Department of Medical Biophysics, University of Western Ontario, London, ON, Canada Abstract: Mesenchymal stem cells (MSC are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migration within the body, and to quantify their accumulation at the target. Cellular magnetic resonance imaging (MRI using fluorine-based nanoemulsions is a great means to detect these transplanted cells in vivo because of the high specificity for fluorine detection and the capability for precise quantification. This technique, however, has low sensitivity, necessitating improvement in MR sequences. To counteract this issue, the balanced steady-state free precession (bSSFP imaging sequence can be of great interest due to the high signal-to-noise ratio (SNR. Furthermore, it can be applied to obtain 3D images within short acquisition times. In this paper, bSSFP provided accurate quantification of samples of the perfluorocarbon Cell Sense-labeled cells in vitro. Cell Sense was internalized by human MSC (hMSC without adverse alterations in cell viability or differentiation into adipocytes/osteocytes. The bSSFP sequence was applied in vivo to track and quantify the signals from both Cell Sense-labeled and iron-labeled hMSC after intramuscular implantation. The fluorine signal was observed to decrease faster and more significantly than the volume of iron-associated voids, which points to the advantage of quantifying the fluorine signal and the complexity of quantifying signal loss due to iron. Keywords: bSSFP, fluorine MRI, mesenchymal stem cell, mouse, cell tracking

  18. In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence.

    Science.gov (United States)

    Ribot, Emeline J; Gaudet, Jeffrey M; Chen, Yuhua; Gilbert, Kyle M; Foster, Paula J

    2014-01-01

    Mesenchymal stem cells (MSC) are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migration within the body, and to quantify their accumulation at the target. Cellular magnetic resonance imaging (MRI) using fluorine-based nanoemulsions is a great means to detect these transplanted cells in vivo because of the high specificity for fluorine detection and the capability for precise quantification. This technique, however, has low sensitivity, necessitating improvement in MR sequences. To counteract this issue, the balanced steady-state free precession (bSSFP) imaging sequence can be of great interest due to the high signal-to-noise ratio (SNR). Furthermore, it can be applied to obtain 3D images within short acquisition times. In this paper, bSSFP provided accurate quantification of samples of the perfluorocarbon Cell Sense-labeled cells in vitro. Cell Sense was internalized by human MSC (hMSC) without adverse alterations in cell viability or differentiation into adipocytes/osteocytes. The bSSFP sequence was applied in vivo to track and quantify the signals from both Cell Sense-labeled and iron-labeled hMSC after intramuscular implantation. The fluorine signal was observed to decrease faster and more significantly than the volume of iron-associated voids, which points to the advantage of quantifying the fluorine signal and the complexity of quantifying signal loss due to iron.

  19. In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence

    OpenAIRE

    Ribot, Emeline J; Gaudet, Jeffrey M; Chen, Yuhua; Gilbert, Kyle M; Foster, Paula J

    2014-01-01

    Emeline J Ribot,1 Jeffrey M Gaudet,1,2 Yuhua Chen,1 Kyle M Gilbert,1 Paula J Foster1,2 1Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada; 2Department of Medical Biophysics, University of Western Ontario, London, ON, Canada Abstract: Mesenchymal stem cells (MSC) are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migra...

  20. Dietary intake and burden of lanthanide in main organs and tissues for Chinese man

    International Nuclear Information System (INIS)

    Zhu Hongda; Liu Qingfeng; Ouyang Li; Liu Husheng; Wang Naifen; Liu Yaqiong; Zhang Yongbao; Wang Ke; Chen Rusong

    2004-01-01

    Objective: To determine lanthanide concentrations in dietary foods and main organs or tissues for Chinese adult man and to estimate their daily intakes by ingestion and organ or tissue burdens. Methods: Ten kinds of organ or tissue samples collected in autopsy from 21 supplemental subjects of 4 areas with different dietary types in China who died suddenly, and had been healthy and normal before death. The concentrations of 11 lanthanide in foods and 14 lanthanide in these organ or tissue samples, including those collected from 31 subjects in the past, were analyzed by using ICP-MS or INAA technique as well as necessary QC measures. With uses of the local diet composition and relevant organ or tissue weights for Chinese Reference Man, their daily intakes and organ or tissue burdens were estimated. Results: The concentrations of 14 lanthanide in 12 categories of foods and 10 kinds of organ or tissue samples, their dietary daily intakes and organ or tissue burdens for Chinese adult men were obtained. Conclusion: Besides updating the relevant data of La, Ce and Eu in 5 kinds of organ or tissue and diet, this research obtained data on concentrations of other 11 lanthanide in Chinese foods and 10 kinds of organ or tissue, their daily intakes and burdens for the first time in China. The results provide more systematic bases for developing the parameters of Chinese Reference Man than before. This study provides also comparative data for different kinds of lanthanide, foods, organs or tissues and also the background values of Chinese soil

  1. Investigation of the photoluminescence properties of composite optical resins containing high lanthanide content

    International Nuclear Information System (INIS)

    Wang Dongmei; Wang Fuxiang; Peng Weixian

    2012-01-01

    Novel composite optical resins with high lanthanide content have been synthesized through a free radical copolymerization of methacrylic acid (MA), styrene (St) and Eu(DBM) 3 ·H 2 O nanocrystals. We characterized the structure, the thermal properties, dimensions and photoluminescence properties of Eu(DBM) 3 ·H 2 O nanocrystals. Our results indicated that the diameters of the Eu(DBM) 3 ·H 2 O nanocrystals were within the range of 30 to 300 nm. These materials exhibited characteristic europium ion luminescence. The europium-bearing nanocrystals and were then incorporated into the copolymer systems of MA/St and luminescence functional optical resins with high lanthanide content (50 wt%) were obtained. The combination of these particles and optical resins is facile because the diameter of Eu(DBM) 3 ·H 2 O is decreased. These copolymer-based optical resins not only possess good transparency and mechanical performance, but also exhibit an intense narrow band emission of lanthanide complexes and longer fluorescence lifetimes under UV excitation at room temperature. - Highlights: ► Novel composite optical resins with high lanthanide content have been synthesized. ► The Eu(DBM) 3 ·H 2 O nanocrystals were within the range of 30 to 300 nm. ► Fluorescent resins with high lanthanide content (50 wt%) were obtained. ► Resins exhibit intense emission of lanthanide and longer fluorescence lifetimes. ► Variety properties of Eu(DBM) 3 ·H 2 O nanocrystals were characterized.

  2. Development of ion imprinted polymers for the selective extraction of lanthanides from environmental samples

    International Nuclear Information System (INIS)

    Moussa, Manel

    2016-01-01

    The analysis of the lanthanide ions present at trace level in complex environmental matrices requires often a purification and preconcentration step. The solid phase extraction (SPE) is the most used sample preparation technique. To improve the selectivity of this step, Ion Imprinted Polymers (IIPs) can be used as SPE solid supports. The aim of this work was the development of IIPs for the selective extraction of lanthanide ions from environmental samples. In a first part, IIPs were prepared according to the trapping approach using 5,7-dichloroquinoline-8-ol as non-vinylated ligand. For the first time, the loss of the trapped ligand during template ion removal and sedimentation steps was demonstrated by HPLC-UV. Moreover, this loss was not repeatable, which led to a lack of repeatability of the SPE profiles. It was then demonstrated that the trapping approach is not appropriate for the IIPs synthesis. In a second part, IIPs were synthesized by chemical immobilization of methacrylic acid as vinylated monomer. The repeatability of the synthesis and the SPE protocol were confirmed. A good selectivity of the IIPs for all the lanthanide ions was obtained. IIPs were successfully used to selectively extract lanthanide ions from tap and river water. Finally, IIPs were synthesized by chemical immobilization of methacrylic acid and 4-vinylpyridine as functional monomers and either a light (Nd 3+ ) or a heavy (Er 3+ ) lanthanide ion as template. Both kinds of IIPs led to a similar selectivity for all lanthanide ions. Nevertheless, this selectivity can be modified by changing the nature and the pH of the washing solution used in the SPE protocol. (author)

  3. 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)

  4. Radiation-induced electron paramagnetic resonance signal and soybean isoflavones content

    International Nuclear Information System (INIS)

    Oliveira, Marcos R.R. de; Mandarino, José M.G.; Mastro, Nelida L. del

    2012-01-01

    Electron Paramagnetic Resonance (EPR) is a well-known spectroscopic technique that detects paramagnetic centers and can detect free radicals with high sensitivity. In food, free radicals can be generated by several commonly used industrial processes, such as radiosterilization or heat treatment. EPR spectroscopy is used to detect radioinduced free radicals in food. In this work the relation between EPR signal induced by gamma irradiation treatment and soybean isoflavones content was investigated. Present results did not show correlation between total isoflavones content and the EPR signal. Nevertheless, some isoflavone contents had a negative correlation with the radiation-induced EPR signal. - Highlights: ► Electron Paramagnetic Resonance (EPR) detects free radicals. ► Ionizing radiation as free radicals inducer. ► Total soybean isoflvones do not correlate with radiation-induced EPR intensity but a soybean glucosyl glucoside isoflavone does.

  5. Paramagnetic resonance and susceptibility of ilmenite, FeTiO3 crystal

    Science.gov (United States)

    Mcdonald, P. F.; Parasiris, A.; Pandey, R. K.; Gries, B. L.; Kirk, W. P.

    1991-01-01

    Large high-purity single crystals of FeTiO3 with ilmenite structure have been grown from a stoichiometric melt of Fe2O3 and TiO2 under an inert atmosphere using the modified Czochralski technique. Susceptibility and X-band paramagnetic resonance studies have been performed. Susceptibility measurements indicate a Neel temperature of about 59 K. The paramagnetic resonance spectrum for magnetic field perpendicular to the crystal c axis consists of a portion of a single, very intense approximately Lorentzian absorption line with its peak at about 600 G and half width at half maximum almost 1200 G. The absorption extends to zero magnetic field. For magnetic field approximately parallel to the c axis, the paramagnetic absorption is much smaller and may be considered a superposition of two approximately Lorentzian line shapes. The magnetic resonance measurements indicate a weak temperature dependence and large angular anisotropy.

  6. Refinement of the ferri and paramagnetic phases of magnetite measured by neutron multiple diffraction

    International Nuclear Information System (INIS)

    Mazzochi, V.L.; Parente, C.B.R.

    1989-10-01

    Structural parameters of the ferri and paramagnetic phases of magnetite have been refined from neutron multiple diffraction data. Experimental patterns were obtained by measuring the III primary reflection of a natural single crystal of this compound, at room temperature for the ferrimagnetic phase and 703 0 C for the paramagnetic phase. Theoretical multiple diffraction patterns for both phases have been calculated by the program MULTI which uses the iterative method. In this method intensities are caluclated as Taylor series expansions summed up to a order sufficient for a good approximation. A step by step process has been used in the refinements similarly to the parameter-shift method. Final values for the discrepancy factor found for the ferri and paramagnetic phases were R = 3.96% and R = 3.46%, respectively. (author) [pt

  7. A fundamental self-generated quenching center for lanthanide-doped high-purity solids

    International Nuclear Information System (INIS)

    Auzel, F.

    2002-01-01

    An intrinsic self-generated quenching center for lanthanide-doped high-purity solids is presented for transitions, which cannot be quenched by cross-relaxation. This center, in fact a cluster-like pair of active centers, is shown to come from a particular multiphonon-assisted energy transfer between them. Being due to the vibronic properties of the host it cannot be suppressed. Its role in lanthanide first excited states self-quenching is analyzed and a simple mathematical expression is derived. This law is compared with experimental results for self-quenching in Er-doped fluorophosphate glasses

  8. 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

  9. Lanthanide mixed ligand chelates for DNA profiling and latent fingerprint detection

    Science.gov (United States)

    Menzel, E. R.; Allred, Clay

    1997-02-01

    It is our aim to develop a universally applicable latent fingerprint detection method using lanthanide (rare-earth) complexes as a source of luminescence. Use of these lanthanide complexes offers advantages on several fronts, including benefits from large Stokes shifts, long luminescence lifetimes, narrow emissions, ability of sequential assembly of complexes, and chemical variability of the ligands. Proper exploitation of these advantages would lead to a latent fingerprint detection method superior to any currently available. These same characteristics also lend themselves to many of the problems associated with DNA processing in the forensic science context.

  10. Luminescence and host lattice structure of crystalline micro and nanoparticles co-doped with lanthanide ions

    International Nuclear Information System (INIS)

    Zurba, Nadia Khaled; Ferreira, Jose Maria da Fonte

    2012-01-01

    This article reports the investigation of crystalline micro and nanoparticles codoped with lanthanide ions, aiming at correlate their host lattice structure and chemical composition to the luminescence features. For this purpose, five phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled to energy dispersive X-ray (EDX) spectroscopy, and photoluminescence (PL) spectroscopy, namely performed by their chromatic coordinates, radiance, luminance and PL emission spectra. This type of investigation concerning the optical characterization of luminescent crystalline micro and nanoparticles doped with lanthanide ions might be useful for scientific and practical applications, such as in light-emitting devices, luminescent paintings, ceramics, sensors, in nanoscience and nanotechnology. (author)

  11. Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Sabrina

    2015-05-13

    This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

  12. Contribution to the study of pseudohalides complexes of tervalent, lanthanides and actinides in solution

    International Nuclear Information System (INIS)

    Cuillerdier, Christine.

    1981-10-01

    Some complexes formed with halides or pseudohalides (iodide, cyanide, azide and thiocyanate) and tervalent lanthanides and actinides have been studied in solution. Methods like solvent extraction, polarography have been used to measure inner plus outer sphere complexation and spectroscopic methods have been chosen to study inner sphere complexes only. It has been found that inner sphere complexe of americium and neodymium with cyanide exist in aqueous solutions. Tervalent actinides form stronger inner sphere complexes with azide than lanthanide in solution. Thiocyanate complexes appear to be inner sphere and N-bonded [fr

  13. Method of growing yttrium aluminate and/or lanthanide single crystals with perovskite structure

    International Nuclear Information System (INIS)

    Kvapil, Jiri; Perner, B.; Kvapil, Josef; Blazek, K.

    1989-01-01

    Single crystals of yttrium aluminate and/or lanthanide with perovskite structure are grown from melt in a vacuum at a pressure of gas residues of max. 0.01 Pa. The melt contains 1±0.05 gram-ions of aluminium per gram-ion of yttrium and/or lanthanides. The single crystals are then heated in a vacuum (0.01 Pa) at temperatures of 1,450 to 1,800 degC for 2 to 3 hours. (B.S.)

  14. Systematic comparisons between the 4d spectra of lanthanide atoms and solids

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, E R [Bonn Univ. (Germany, F.R.). Physikalisches Inst.

    1979-02-14

    It is shown that the lanthanides can be divided into two groups according to the occupation of the 4f subshell in the solid and in the atom. In the first group the 4d absorption spectrum in the atom and in the solid are similar. In the second group the atomic spectrum of the element with nuclear charge Z corresponds to the solid with nuclear charge (Z + 1). Predictions are made for the 4d spectra of those lanthanides which remain to be observed.

  15. Systematic comparisons between the 4d spectra of lanthanide atoms and solids

    International Nuclear Information System (INIS)

    Radtke, E.R.

    1979-01-01

    It is shown that the lanthanides can be divided into two groups according to the occupation of the 4f subshell in the solid and in the atom. In the first group the 4d absorption spectrum in the atom and in the solid are similar. In the second group the atomic spectrum of the element with nuclear charge Z corresponds to the solid with nuclear charge (Z + 1). Predictions are made for the 4d spectra of those lanthanides which remain to be observed. (author)

  16. Comparison of the thermodynamic properties and high temperature chemical behavior of lanthanide and actinide oxides

    International Nuclear Information System (INIS)

    Ackermann, R.J.; Rauh, E.G.

    1977-01-01

    The thermodynamic properties of the lanthanide and actinide oxides are examined, compared, and associated with a variety of high temperature chemical behavior. Trends are cited resulting from a number of thermodynamic and spectroscopic correlations involving solid phases, species in aqueous solution, and molecules and ions in the vapor phase. Inadequacies in the data and alternative approaches are discussed. The characterization of nonstoichiometric phases stable only at high temperatures is related to a network of heterogeneous and homogeneous equilibria. A broad perspective of similarity and dissimilarity between the lanthanides and actinides emerges and forms the basis of the projected needs for further study

  17. Complexes of trivalent lanthanide ions with schiff base derived from vanillin and triethylenetetraamine

    International Nuclear Information System (INIS)

    Shahma, A.; Athar, M.; Ahmad, N.

    1982-01-01

    Complexes of lanthanide(III) ions with the schiff base derived from vanillin and triethylenetetraamine have been synthesised and characterised on the basis of elemental analyses, molar conductance, magnetic moment, IR and thermal analysis data. The thermograms show the elimination (OH)(OCH 3 )C 6 H 3 CH-group at low temperatures before the elimination of triethylenetetraamine part corroborating the observation made on the basis of IR spectral data. This is a clear indication of the non-coordination of the phenolic hydroxyl groups. The lanthanide ions in the complexes exhibit eight coordination numbers. (author)

  18. Synthesis, characterization and properties of lanthanide trifluoroacetate complexes with N-(1-adamantyl) acetamide

    International Nuclear Information System (INIS)

    Miranda Junior, P.; Isolani, P.C.; Vicentini, G.; Zinner, L.B.

    1999-01-01

    Complexes of lanthanide trifluoacetates and N-(1-adamantyl) acetamide (ADA) with composition Ln (TFA) 3 .ADA (Ln=Nd, Sm, Eu, Gd, Tb, Dy; TFA trifluoroacetate) were synthesized by titration of lanthanides with EDTA and CHN microanalytical procedures. According to IR spectra the bonding of ADA occurs through the carbonyl oxygen. Compounds of Nd 3+ , Sm 3+ and Eu 3+ present two bands attributed to v aa COO and that of Gd 3+ Tb 3+ only one. In all cases only one band is attributed to v a -s COO. The absorption spectra of the neodymium and the emission spectra of the europium compounds were determined and interpreted. (author)

  19. A stimuli-responsive smart lanthanide nanocomposite for multidimensional optical recording and encryption

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang; Xie, Yujie; Zhang, Hao-Li; Chen, Hao; Cai, Huijuan; Liu, Weisheng; Tang, Yu [State Key Lab. of Applied Organic Chemistry, Key Lab. of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou Univ. (China); Song, Bo [State Key Lab. of Fine Chemicals, School of Chemistry, Dalian Univ. of Technology, Dalian (China)

    2017-03-01

    A stimuli-responsive lanthanide-based smart nanocomposite has been fabricated by supramolecular assembly and applied as an active material in multidimensional memory materials. Conjugation of the lanthanide complexes with carbon dots provides a stimuli response that is based on the modulation of the energy level of the ligand and affords microsecond-to-nanosecond fluorescence lifetimes, giving rise to intriguing memory performance in the spatial and temporal dimension. The present study points to a new direction for the future development of multidimensional memory materials based on inorganic-organic hybrid nanosystems. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate for dual biosensing of pH with chemical exchange saturation transfer (CEST) and biosensor imaging of redundant deviation in shifts (BIRDS).

    Science.gov (United States)

    Huang, Yuegao; Coman, Daniel; Ali, Meser M; Hyder, Fahmeed

    2015-01-01

    Relaxivity-based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd(3+)) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the nonexchangeable or the exchangeable protons on the lanthanide complexes themselves. The nonexchangeable protons (e.g. -CHx, where 3 ≥ x ≥ 1) are detected using a three-dimensional chemical shift imaging method called biosensor imaging of redundant deviation in shifts (BIRDS), whereas the exchangeable protons (e.g. -OH or -NHy , where 2 ≥ y ≥ 1) are measured with chemical exchange saturation transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP(8-)) chelated with thulium (Tm(3+) ) and ytterbium (Yb(3+)). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e. 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP(5-) than with TmDOTA-4AmP(5-). In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging. Copyright © 2014 John Wiley & Sons, Ltd.

  1. 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

  2. Role of paramagnetic chromium in chromium(VI)-induced damage in cultured mammalian cells.

    OpenAIRE

    Sugiyama, M

    1994-01-01

    Chromium(VI) compounds are known to be potent toxic and carcinogenic agents. Because chromium(VI) is easily taken up by cells and is subsequently reduced to chromium(III), the formation of paramagnetic chromium such as chromium(V) and chromium(III) is believed to play a role in the adverse biological effects of chromium(VI) compounds. The present report, uses electron spin resonance (ESR) spectroscopy; the importance of the role of paramagnetic chromium in chromium(VI)-induced damage in intac...

  3. Measurement of electron paramagnetic resonance using terahertz time-domain spectroscopy.

    Science.gov (United States)

    Kozuki, Kohei; Nagashima, Takeshi; Hangyo, Masanori

    2011-12-05

    We present a frequency-domain electron spin resonance (ESR) measurement system using terahertz time-domain spectroscopy. A crossed polarizer technique is utilized to increase the sensitivity in detecting weak ESR signals of paramagnets caused by magnetic dipole transitions between magnetic sublevels. We demonstrate the measurements of ESR signal of paramagnetic copper(II) sulfate pentahydrate with uniaxial anisotropy of the g-factor under magnetic fields up to 10 T. The lineshape of the obtained ESR signals agrees well with the theoretical predictions for a powder sample with the uniaxial anisotropy.

  4. Pauli Paramagnetic Susceptibility of an Ideal Anyon Gas within Haldane Fractional Exclusion Statistics

    International Nuclear Information System (INIS)

    Qin Fang; Chen Jisheng

    2012-01-01

    The finite-temperature Pauli paramagnetic susceptibility of a three-dimensional ideal anyon gas obeying Haldane fractional exclusion statistics is studied analytically. Different from the result of an ideal Fermi gas, the susceptibility of an ideal anyon gas depends on a statistical factor g in Haldane statistics model. The low-temperature and high-temperature behaviors of the susceptibility are investigated in detail. The Pauli paramagnetic susceptibility of the two-dimensional ideal anyons is also derived. It is found that the reciprocal of the susceptibility has the similar factorizable property which is exhibited in some thermodynamic quantities in two dimensions.

  5. Susceptibility cancellation of a microcoil wound with a paramagnetic-liquid-filled copper capillary

    Science.gov (United States)

    Takeda, Kazuyuki; Takasaki, Tomoya; Takegoshi, K.

    2015-09-01

    Even though microcoils improve the sensitivity of NMR measurement of tiny samples, magnetic-field inhomogeneity due to the bulk susceptibility effect of the coil material can cause serious resonance-line broadening. Here, we propose to fabricate the microcoil using a thin, hollow copper capillary instead of a wire and fill paramagnetic liquid inside the capillary, so as to cancel the diamagnetic contribution of the copper. Susceptibility cancellation is demonstrated using aqueous solution of NiSO4. In addition, the paramagnetic liquid serves as coolant when it is circulated through the copper capillary, effectively transferring the heat generated by radiofrequency pulses.

  6. Silver baits for the "miraculous draught" of amphiphilic lanthanide helicates.

    Science.gov (United States)

    Terazzi, Emmanuel; Guénée, Laure; Varin, Johan; Bocquet, Bernard; Lemonnier, Jean-François; Emery, Daniel; Mareda, Jiri; Piguet, Claude

    2011-01-03

    The axial connection of flexible thioalkyls chains of variable length (n=1-12) within the segmental bis-tridentate 2-benzimidazole-8-hydroxyquinoline ligands [L12(Cn) -2 H](2-) provides amphiphilic receptors designed for the synthesis of neutral dinuclear lanthanides helicates. However, the stoichiometric mixing of metals and ligands in basic media only yields intricate mixtures of poorly soluble aggregates. The addition of Ag(I) in solution restores classical helicate architectures for n=3, with the quantitative formation of the discrete D(3) -symmetrical [Ln(2) Ag2(L12(C3) -2 H)(3) ](2+) complexes at millimolar concentration (Ln=La, Eu, Lu). The X-ray crystal structure supports the formation of [La(2) Ag(2) (L12(C3) -2 H)(3) ][OTf](2) , which exists in the solid state as infinite linear polymers bridged by S-Ag-S bonds. In contrast, molecular dynamics (MD) simulations in the gas phase and in solution confirm the experimental diffusion measurements, which imply the formation of discrete molecular entities in these media, in which the sulfur atoms of each lipophilic ligand are rapidly exchanged within the Ag(I) coordination sphere. Turned as a predictive tool, MD suggests that this Ag(I) templating effect is efficient only for n=1-3, while for n>3 very loose interactions occur between Ag(I) and the thioalkyl residues. The subsequent experimental demonstration that only 25 % of the total ligand speciation contributes to the formation of [Ln(2) Ag(2) (L12(C12) -2 H)(3) ](2+) in solution puts the bases for a rational approach for the design of amphiphilic helical complexes with predetermined molecular interfaces. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Advanced Extraction Methods for Actinide/Lanthanide Separations

    International Nuclear Information System (INIS)

    Scott, M.J.

    2005-01-01

    The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form

  8. Advanced Extraction Methods for Actinide/Lanthanide Separations

    Energy Technology Data Exchange (ETDEWEB)

    Scott, M.J.

    2005-12-01

    The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form

  9. Medium temperature reaction between lanthanide and actinide carbides and hydrogen; Reaction a temperature moyenne entre les monocarbures de lanthanides et d'actinides et l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Dean, G; Lorenzelli, R; Pascard, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    Hydrogen is fixed reversibly by the lanthanide and actinide mono carbides in the range 25 - 400 C, as for pure corresponding metals. Hydrogen goes into the carbides lattice through carbon vacancies and the total fixed amount is approximately equal to two hydrogen atoms per initial vacancy. Final products c.n thus be considered as carbo-hydrides of general formula M(C{sub 1-x}, H{sub 2x}). The primitive CFC, NaCl type, structure remains unchanged but expands strongly in the case of actinide carbides. With lanthanide carbides, hydrogenation induces a phase transformation with reappearance of the metal structure (HCP). Hydrogen decomposition pressures of all the studied carbo-hydrides are greater than those of the corresponding di-hydrides. (authors) [French] Les monocarbures d'actinides et de lanthanides fixent reversiblement de l'hydrogene a temperature peu elevee, a peu pres dans les memes conditions que les metaux purs correspondants. L'hydrogene penetre dans le reseau des carbures par l'intermediaire des lacunes de carbone, et la quantite totale fixee est approximativement egale a deux atomes d'hydrogene par lacune initiale. Les produits obtenus peuvent donc etre consideres comme des carbohydrures de formule generale M(C{sub 1-x}, H{sub 2x}). La structure d'origine CFC, type NaCl est conservee, mais avec une forte expansion, dans le cas des carbures d'actinides. En revanche, l'hydrogenation entraine un changement de phase cristalline avec retour a la structure du metal (HC) pour les carbures de lanthanides. Tous les carbohydrures etudies ont des tensions de decomposition en hydrogene superieures a celles des dihydrures correspondants. (auteurs)

  10. Approximate estimation method of the degree of lanthanide tetr[ effect and application to the tetr[ effects in lanthanide ionic r[ii

    International Nuclear Information System (INIS)

    Minami, M.

    1998-01-01

    Fitting of qu[ratic curves to four defined subgroups of lanthanides shows that the tetr[ effects in Ln 3+ ionic r[ii with coordination number (CN) 6 are larger than those with CN 8. The features for the first tetr[ are peculiar compared with other three subgroups, with both CN. The observed facts can be explained in terms of configuration of 4f electron clouds and their interaction with ligands. (orig.)

  11. Actinides(3)/lanthanides(3) separation by nano-filtration assisted by complexation; Separation actinides(3)lanthanides(3) par nanofiltration assistee par complexation

    Energy Technology Data Exchange (ETDEWEB)

    Sorin, A

    2006-07-01

    In France, one of the research trend concerning the reprocessing of spent nuclear fuel consists to separate selectively the very radio-toxic elements with a long life to be recycled (Pu) or transmuted (Am, Cm, Np). The aim of this thesis concerns the last theme about actinides(III)/lanthanides(III) separation by a process of nano-filtration assisted by complexation. Thus, a pilot of tangential membrane filtration was designed and established in a glove box at the ATALANTE place of CEA-Marcoule. Physico-chemical characterisation of the Desal GH membrane (OSMONICS), selected to carry out actinides(III)/lanthanides(III) separation, was realized to determine the zeta potential of the active layer and its resistance to ionizing radiations. Moreover, a parametric study was also carried out to optimize the selectivity of complexation, and the operating conditions of complex retention (influences of the transmembrane pressure, solute concentration, tangential velocity and temperature). Finally, the separation of traces of Am(III) contained in a mixture of lanthanides(III), simulating the real load coming from a reprocessing cycle, was evaluated with several chelating agents such as poly-amino-carboxylic acids according to the solution acidity and the [Ligand]/[Cation(III)] ratio. (author)

  12. Silica-modified monodisperse hexagonal lanthanide nanocrystals: synthesis and biological properties

    Czech Academy of Sciences Publication Activity Database

    Kostiv, Uliana; Janoušková, Olga; Šlouf, Miroslav; Kotov, Nikolay; Engstová, Hana; Smolková, Katarína; Ježek, Petr; Horák, Daniel

    2015-01-01

    Roč. 7, č. 43 (2015), s. 18096-18104 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-01897S Institutional support: RVO:61389013 ; RVO:67985823 Keywords : upconverting * nanoparticles * lanthanide Subject RIV: CD - Macromolecular Chemistry; FD - Oncology ; Hematology (FGU-C) Impact factor: 7.760, year: 2015

  13. Magnetic Properties of linear chain compounds formed by lanthanide (III) ions and nitronyl-nitroxide radicals

    Energy Technology Data Exchange (ETDEWEB)

    Benelli, C.; Caneschi, A.; Gatteschi, D.; Pardi, L. (Florence Univ. (IT)); Rey, P. (CEA Centre d' Etudes Nucleaires de Grenoble, 38 (FR). Dept. de Recherche Fondamentale)

    1988-12-01

    The magnetic properties of novel linear chain compounds containing lanthanide (III) ions (gadolinium, europium) coupled to stable nitronyl-nitroxide radicals are reported. The metal ions and the radicals are regularly alternating along the chain. The magnetic behaviors appears to be dominated by antiferromagnetic interactions between the radicals.

  14. Magnetic Properties of linear chain compounds formed by lanthanide (III) ions and nitronyl-nitroxide radicals

    International Nuclear Information System (INIS)

    Benelli, C.; Caneschi, A.; Gatteschi, D.; Pardi, L.; Rey, P.

    1988-01-01

    The magnetic properties of novel linear chain compounds containing lanthanide (III) ions (gadolinium, europium) coupled to stable nitronyl-nitroxide radicals are reported. The metal ions and the radicals are regularly alternating along the chain. The magnetic behaviors appears to be dominated by antiferromagnetic interactions between the radicals

  15. N,N-dimethylformamide (dMF) adducts of lanthanide trifluoroacetates

    International Nuclear Information System (INIS)

    Vicentini, G.; Silva, M.G. da

    1984-01-01

    Addition compounds of lanthanide iodides, acetates, nitrates, perchlorates, chlorides, perhenates, hexathiocyanates, chromiates, isothiocyanates and hexafluorophosphates with DMF have been extensively described in the literature. This article reports the preparation and characterization of adducts with general formula Ln(CF 3 COO) 3 . 2 DMF. (Author) [pt

  16. 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)

  17. Detection of phosphorylation states by intermolecular sensitization of lanthanide-peptide conjugates.

    Science.gov (United States)

    Pazos, Elena; Goličnik, Marko; Mascareñas, José L; Vázquez, M Eugenio

    2012-10-04

    The luminescence of a designed peptide equipped with a coordinatively-unsaturated lanthanide complex is modulated by the phosphorylation state of a serine residue in the sequence. While the phosphorylated state is weakly emissive, even in the presence of an external antenna, removal of the phosphate allows coordination of the sensitizer to the metal, yielding a highly emissive supramolecular complex.

  18. 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.

  19. Controlled synthesis of bright and compatible lanthanide-doped upconverting nanocrystals

    Science.gov (United States)

    Cohen, Bruce E.; Ostrowski, Alexis D.; Chan, Emory M.; Gargas, Daniel J.; Katz, Elan M.; Schuck, P. James; Milliron, Delia J.

    2017-01-31

    Certain nanocrystals possess exceptional optical properties that may make them valuable probes for biological imaging, but rendering these nanoparticles biocompatible requires that they be small enough not to perturb cellular systems. This invention describes a phosphorescent upconverting sub-10 nm nanoparticle comprising a lanthanide-doped hexagonal .beta.-phase NaYF.sub.4 nanocrystal and methods for making the same.

  20. Study of electron spectra of lanthanide complexes with carbonyl-containing reagents

    International Nuclear Information System (INIS)

    Tishchenko, M.A.; Gerasimenko, G.I.; Markina, A.I.; Tishchenko, V.V.; Rybalka, V.B.; Tsitko, A.S.

    1990-01-01

    Interaction of lanthanide complexes (Ln=Er, Nd, Ho) of 2-acetylindandione-1,3 with polyphenols was investigated by the methods of electron spectroscopy. Position, intensity, oscillator strengths of supersensitive transitions, formed in the system of different-ligand complexes were determined. 10 refs.; 4 figs.; 3 tabs

  1. 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

  2. Coordination polymers of some lanthanide(III) nitrate with schiff bases

    International Nuclear Information System (INIS)

    Dwivedi, D.K.; Shukla, B.K.; Shukla, R.K.

    1991-01-01

    The Schiff bases derived from 2-hydroxy-1-naphthaldehyde and salicylaldehyde with o-dianisidine, p-phenylene diamine and benzidine and their lanthanide(III) complexes have been synthesized and characterized by elemental, I.R., thermal, magnetic and D.R.S. studies. (author). 7 refs

  3. 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)

  4. Study on the phosphate reaction characteristics of lanthanide chlorides in molten salt with operating conditions

    International Nuclear Information System (INIS)

    Lee, Tae-Kyo; Hwang, Taek-Sung; Cho, Yung-Zun; Eun, Hee-Chul; Park, Hwan-Seo; Park, Geun-Il; Son, Sung-Mo

    2013-01-01

    A minimization of waste salt is one of the most important issues for the optimization of pyroprocessing. The separation of fission products in waste salts and the reuse of purified waste salt are promising strategies for minimizing the waste salt amounts. The phosphate precipitation of lanthanide is currently being considered for eutectic (LiCl–KCl) waste salt purification. In this research, the effects of molten salt temperature (400–550°C) and reaction time (max. 180 min) upon conversion into the phosphate of lanthanides was investigated using 1 and 3 kg of eutectic salt. The conversion efficiency of lanthanides to molten salt-insoluble precipitates and phosphates was increased with an increase in molten salt temperature and operating time until it attained a specific temperature and time. K 3 PO 4 as a precipitant was more favorable than Li 3 PO 4 in terms of reactivity. To obtain over a 99% overall conversion efficiency, about 30 min was required in the case of using K 3 PO 4 at 450°C, but about 120 min in the case of using Li 3 PO 4 at 550°C. The lanthanide precipitates formed by a reaction with phosphate were a mixture of monoclinic structures, usually representing a polyhedron structure, and a tetragonal structure, representing a platelet structure. (author)

  5. Using remote substituents to control solution structure and anion binding in lanthanide complexes

    DEFF Research Database (Denmark)

    Tropiano, Manuel; Blackburn, Octavia A.; Tilney, James A.

    2013-01-01

    A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery ...

  6. Thermal decomposition of double selenates of lanthanides (III), yttrium (III) and ammonium

    International Nuclear Information System (INIS)

    Crespi, M.S.

    1989-01-01

    Double selenates of lanthanides, yttrium and ammonium were prepared by treating mixtures of simple selenates with equimolar amounts and then dried in a vacuum desiccator containing anhydrous calcium chloride, protected from light. The compounds were studied using the conventional analytical methods such as infrared absorption spectra, X-ray diffraction, differential thermal analysis (DTA), and thermogravimetry (TG). (author)

  7. Direct conversion of glucose to 5-(hydroxymethyl)furfural in ionic liquids with lanthanide catalysts

    DEFF Research Database (Denmark)

    Ståhlberg, Tim; Sørensen, Mathilde Grau; Riisager, Anders

    2010-01-01

    The direct conversion of glucose to 5-(hydroxymethyl)furfural (HMF) in ionic liquids with lanthanide catalysts was examined in search of a possibly more environmentally feasible process not involving chromium. The highest HMF yield was obtained with ytterbium chloride or triflate together...

  8. 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.

  9. 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...

  10. Electrolytic production of light lanthanides from molten chloride alloys on a large laboratory scale

    International Nuclear Information System (INIS)

    Szklarski, W.; Bogacz, A.; Strzyzewska, M.

    1979-01-01

    Literature data relating to electrolytic production of rare earth metals are presented. Conditions and results are given of own investigations into the electrolytic process of light lanthanide chloride solutions (LA-Nd) in molten potassium and sodium chlorides conducted on a large laboratory scale using molybdenic, iron, cobaltic and zinc cathodes. Design schemes of employed electrolysers are enclosed. (author)

  11. 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.

  12. Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

    Science.gov (United States)

    Ueno, K.; Toibana, Y.

    1984-01-01

    The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

  13. Lanthanide 4f-level location in AVO4:Ln3+ (A = La, Gd, Lu) crystals

    NARCIS (Netherlands)

    Krumpel, A.H.; Van der Kolk, E.; Cavalli, E.; Boutinaud, P.; Bettinelli, M.; Dorenbos, P.

    2009-01-01

    The spectral properties of LaVO4, GdVO4 and LuVO4 crystals doped with Ce3+, Pr3+, Eu3+ or Tb3+ have been investigated in order to determine the position of the energy levels relative to the valence and conduction bands of the hosts along the trivalent and divalent lanthanide series. Pr3+ and Tb3+

  14. 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

  15. Structure and potential applications of amido lanthanide complexes chelated by bifunctional b-diketiminate ligand

    Czech Academy of Sciences Publication Activity Database

    Olejník, R.; Padělková, Z.; Fridrichová, A.; Horáček, Michal; Merna, J.; Růžička, A.

    2014-01-01

    Roč. 759, JUN 2014 (2014), s. 1-10 ISSN 0022-328X R&D Projects: GA ČR GAP106/10/0924 Institutional support: RVO:61388955 Keywords : Bifunctional b-diketiminates * lanthanides * hydroamination Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.173, year: 2014

  16. Lanthanide Phytanates: Liquid-Crystalline Phase Behavior, Colloidal Particle Dispersions, and Potential as Medical Imaging Agents

    Energy Technology Data Exchange (ETDEWEB)

    Conn, Charlotte E.; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J.; Kennedy, Danielle F.; Drummond, Calum J. (CSIRO/MHT); (CSIRO/MSE)

    2010-08-23

    Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

  17. Lanthanide Phytanates: Liquid-Crystalline Phase Behavior, Colloidal Particle Dispersions, and Potential as Medical Imaging Agents

    International Nuclear Information System (INIS)

    Conn, Charlotte E.; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J.; Kennedy, Danielle F.; Drummond, Calum J.

    2010-01-01

    Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

  18. Polymer Assembly Encapsulation of Lanthanide Nanoparticles as Contrast Agents for In Vivo Micro-CT.

    Science.gov (United States)

    Cruje, Charmainne; Dunmore-Buyze, Joy; MacDonald, Jarret P; Holdsworth, David W; Drangova, Maria; Gillies, Elizabeth R

    2018-03-12

    Despite recent technological advancements in microcomputed tomography (micro-CT) and contrast agent development, preclinical contrast agents are still predominantly iodine-based. Higher contrast can be achieved when using elements with higher atomic numbers, such as lanthanides; lanthanides also have X-ray attenuation properties that are ideal for spectral CT. However, the formulation of lanthanide-based contrast agents at the high concentrations required for vascular imaging presents a significant challenge. In this work, we developed an erbium-based contrast agent that meets micro-CT imaging requirements, which include colloidal stability upon redispersion at high concentrations, evasion of rapid renal clearance, and circulation times of tens of minutes in small animals. Through systematic studies with poly(ethylene glycol) (PEG)-poly(propylene glycol), PEG-polycaprolactone, and PEG-poly(l-lactide) (PLA) block copolymers, the amphiphilic block copolymer PEG 114 -PLA 53 was identified to be ideal for encapsulating oleate-coated lanthanide-based nanoparticles for in vivo intravenous administration. We were able to synthesize a contrast agent containing 100 mg/mL of erbium that could be redispersed into colloidally stable particles in saline after lyophilization. Contrast enhancement of over 250 HU was achieved in the blood pool for up to an hour, thereby meeting the requirements of live animal micro-CT.

  19. Lanthanide-Based Metal Organic Frameworks: Synthetic Strategies and Catalytic Applications

    NARCIS (Netherlands)

    Pagis, C.; Ferbinteanu, M.; Rothenberg, G.; Grecea, S.

    2016-01-01

    This short critical review outlines the main synthetic strategies used in the designed synthesis of lanthanide-based metal organic frameworks (Ln-MOFs). It explains the impact of the choice of organic linker on the final network topology, and it highlights the applications of Ln-MOFs in the

  20. Bioaccumulation pattern of lanthanides in pteridophytes and magnoliophytes species from Atlantic Forest

    International Nuclear Information System (INIS)

    Andre Luis Lima de Araujo; De Nadai Fernandes, E.A.; Marcio Arruda Bacchi; Elvis Joacir De Franca

    2012-01-01

    The availability of chemical elements for plants is mainly dependent on the nature of the soil and characteristics of each species. The transfer factors of lanthanides from the soil to the tree leaves of the Atlantic Forest, Brazil, were calculated for one fern species (Alsophila sternbergii-Pteridophyta division) and four magnoliophytes species (Bathysa australis, Euterpe edulis, Garcinia gardneriana and Guapira opposita-Magnoliophyta division) obtained in two areas of Serra do Mar State Park and collected in two different seasons. Samples were analyzed by instrumental neutron activation analysis (INAA). The soil-to-plant transfer factor (TF = C plant :C soil ) in magnoliophytes species was correlated to the mass fraction of lanthanides in the soil, described by a exponential model (TF = a.C soil -b ). Despite the tree fern Alsophila sternbergii presented a hyperaccumulation of lanthanides, this species did not have a significant relationship between TF and mass fraction in soil. Results indicated that plants of Magnoliophyta division selected the input of lanthanides from the soil, while the same was not observed in Alsophila sternbergii. (author)

  1. Sorption Speciation of Lanthanides/Actinides on Minerals by TRLFS, EXAFS and DFT Studies: A Review

    Directory of Open Access Journals (Sweden)

    Xiaoli Tan

    2010-11-01

    Full Text Available Lanthanides/actinides sorption speciation on minerals and oxides by means of time resolved laser fluorescence spectroscopy (TRLFS, extended X-ray absorption fine structure spectroscopy (EXAFS and density functional theory (DFT is reviewed in the field of nuclear disposal safety research. The theoretical aspects of the methods are concisely presented. Examples of recent research results of lanthanide/actinide speciation and local atomic structures using TRLFS, EXAFS and DFT are discussed. The interaction of lanthanides/actinides with oxides and minerals as well as their uptake are also of common interest in radionuclide chemistry. Especially the sorption and inclusion of radionuclides into several minerals lead to an improvement in knowledge of minor components in solids. In the solid-liquid interface, the speciation and local atomic structures of Eu(III, Cm(III, U(VI, and Np(IV/VI in several natural and synthetic minerals and oxides are also reviewed and discussed. The review is important to understand the physicochemical behavior of lanthanides/actinides at a molecular level in the natural environment.

  2. U, TH and lanthanides in street soils of Sao Paulo city, Brazil

    International Nuclear Information System (INIS)

    Ticianelli, R.B.; Ribeiro, A.P.; Figueiredo, A.M.G.; Zanh, G.S.

    2013-01-01

    The study of lanthanide distribution in urban environments has become of interest over the last years, due to the increased industrial use of these elements. Sao Paulo is the 6th largest metropolitan region of the world, with about 20 million inhabitants in its metropolitan area, more than 9 million motor vehicles and intense industrial activity. There is little information on U, Th, and lanthanide contents in urban soils, and there are as of yet no reference values for these elements in soils of Sao Paulo city. The present study aimed to determine U, Th and lanthanide concentrations in soils adjacent to avenues of highly dense traffic downtown in Sao Paulo city, to assess their possible sources and potential environmental impacts. The analytical technique employed was Instrumental Neutron Activation Analysis (INAA). Th and U levels ranged from 4.0 to 37.0 mg kg -1 and from 1.6 to 18.7 mg kg -1 , respectively. These values are higher than literature values for U and Th in Brazilian superficial soils. The results obtained for the lanthanides indicate enrichment in La and Ce. However, a possible anthropogenic source should be investigated since high background values of these elements may be associated to the natural geological composition of the soils. (author)

  3. On kinetics of paramagnetic radiation defects accumulation in beryllium ceramics; O kinetike nakopleniya paramagnitnykh radiatsionnykh defektov v berillievykh keramikakh

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, A I; Ryabikin, Yu A; Zashkvara, O V; Bitenbaev, M I; Petykhov, Yu V [Fiziko-Tekhnicheskij Inst., Almaty (Kazakhstan); Inst. Atomnoj Ehnergii, Kurchatov (Kazakhstan)

    1999-07-01

    Results of paramagnetic radiation defects concentration dependence study in beryllium ceramics from gamma-irradiation dose ({sup 60}Co) within interval 0-100 Mrem are cited. Obtained dose dependence has form of accumulation curve with saturation typical of for majority of solids (crystals, different polymers, organic substances and others) , in which under irradiation occur not only formation of paramagnetic radiation defects, but its destruction due to recombination and interaction with radiation fields. Analysis of accumulation curve by the method of distant asymptotics allows to determine that observed in gamma-irradiated beryllium ceramics double line of electron spin resonance is forming of two types of paramagnetic radiation defects. It was defined, that sum paramagnetic characteristics of beryllium ceramics within 1-100 Mrad gamma- irradiation dose field change insignificantly and define from first type of paramagnetic radiation defects.

  4. 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.

  5. Pauli paramagnetic effects on vortices in superconducting TmNi2B2C

    DEFF Research Database (Denmark)

    DeBeer-Schmitt, L.; Eskildsen, Morten Ring; Ichioka, M.

    2007-01-01

    The magnetic field distribution around the vortices in TmNi2B2C in the paramagnetic phase was studied experimentally as well as theoretically. The vortex form factor, measured by small-angle neutron scattering, is found to be field independent up to 0.6H(c2) followed by a sharp decrease at higher...

  6. Contribution of electron paramagnetic resonance to the studies of hemoglobin: the nitrosylhemoglobin system

    International Nuclear Information System (INIS)

    Bemski, G.

    1995-03-01

    Since the initial work of Ingram Electron Paramagnetic Resonance contributed considerably to research in hemoglobins. Now, 40 years later some of the results of the application of EPR to nitrosyl hemoglobin (HbNO), are reviewed as an example of the diversity of information which this technique can provide are reviewed. (author). 34 refs, 7 figs

  7. Paramagnetic NMR investigation of dendrimer-based host-guest interactions.

    Directory of Open Access Journals (Sweden)

    Fei Wang

    Full Text Available In this study, the host-guest behavior of poly(amidoamine (PAMAM dendrimers bearing amine, hydroxyl, or carboxylate surface functionalities were investigated by paramagnetic NMR studies. 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO derivatives were used as paramagnetic guest molecules. The results showed that TEMPO-COOH significantly broaden the ¹H NMR peaks of amine- and hydroxyl-terminated PAMAM dendrimers. In comparison, no paramagnetic relaxation enhancement (PRE was observed between TEMPO-NH₂, TEMPO-OH and the three types of PAMAM dendrimers. The PRE phenomenon observed is correlated with the encapsulation of TEMPO-COOH within dendrimer pockets. Protonation of the tertiary amine groups within PAMAM dendrimers plays an important role during this process. Interestingly, the absence of TEMPO-COOH encapsulation within carboxylate-terminated PAMAM dendrimer is observed due to the repulsion of TEMPO-COO- anion and anionic dendrimer surface. The combination of paramagnetic probes and ¹H NMR linewidth analysis can be used as a powerful tool in the analysis of dendrimer-based host-guest systems.

  8. Clean bulk YBaCuO superconductors doped by paramagnetic ions of Sm and Yb

    Czech Academy of Sciences Publication Activity Database

    Jirsa, Miloš; Volochová, D.; Kováč, J.; Diko, P.

    2017-01-01

    Roč. 131, č. 4 (2017), s. 1027-1029 ISSN 0587-4246 Institutional support: RVO:68378271 Keywords : YBaCuO * bulk superconductors * paramagnetic ions * microstructure * vortex pinning Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.469, year: 2016

  9. Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

    1976-01-01

    The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

  10. Effect of paramagnetic manganese cations on H-1 MRS of the brain

    DEFF Research Database (Denmark)

    Madsen, K. S.; Holm, David Alberg; Søgaard, L. V.

    2008-01-01

    Manganese cations (Mn2+) call be used as all intracellular contrast agent for structural, functional and neural pathway imaging applications. However, at high concentrations, Mn2+ is neurotoxic and play influence the concentration of H-1 MR-detectable metabolites. Furthermore, the paramagnetic Mn...

  11. Concentration of paramagnetic centres at low-temperature thermal destruction of asphaltenes of heavy petroleum distillates

    Directory of Open Access Journals (Sweden)

    Dolomatov M.U., Rodionov A.A., Gafurov M.R., Petrov A.V., Biktagirov T.B., Bakhtizin R.Z., Makarchikov S.O., Khairudinov I.Z., Orlinskii S.B.

    2016-11-01

    Full Text Available Changes of paramagnetic centers (PC concentration in dispersed petroleum systems were studied in the process of low-temperature thermolysis. The kinetic model of PC concentration dynamics based on the processes of unpaired electrons formation during singlet-triplet transitions, weak chemical bonds dissociation and recombination of free radicals is proposed.

  12. Identification and Quantification of Copper Sites in Zeolites by Electron Paramagnetic Resonance Spectroscopy

    DEFF Research Database (Denmark)

    Godiksen, Anita; Vennestrøm, Peter N. R.; Rasmussen, Søren Birk

    2017-01-01

    Recent quantitative electron paramagnetic resonance spectroscopy (EPR) data on different copper species present in copper exchanged CHA zeolites are presented and put into context with the literature on other copper zeolites. Results presented herein were obtained using ex situ and in situ EPR...

  13. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers

    KAUST Repository

    Chu, Shidong; Maltsev, Sergey B.; Emwas, Abdul-Hamid M.; Lorigan, Gary A.

    2010-01-01

    A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2

  14. Electron Paramagnetic Resonance and X-ray Diffraction of Boron- and Phosphorus-Doped Nanodiamonds

    Science.gov (United States)

    Binh, Nguyen Thi Thanh; Dolmatov, V. Yu.; Lapchuk, N. M.; Shymanski, V. I.

    2017-11-01

    Powders of boron- and phosphorus-doped detonation nanodiamonds and sintered pellets of non-doped nanodiamond powders were studied using electron paramagnetic resonance and x-ray diffraction. Doping of detonation nanodiamond crystals with boron and phosphorus was demonstrated to be possible. These methods could be used to diagnose diamond nanocrystals doped during shock-wave synthesis.

  15. An EPR study on tea: Identification of paramagnetic species, effect of heat and sweeteners

    Science.gov (United States)

    Bıyık, Recep; Tapramaz, Recep

    2009-10-01

    Tea ( Camellia Sinensis) is the most widely consumed beverage in the world, and is known to be having therapeutic, antioxidant and nutritional effects. Electron paramagnetic resonance (EPR) spectral studies made on the tea cultivated along the shore of Black Sea, Turkey, show Mn 2+ and Fe 3+ centers in green tea leaves and in black tea extract. Dry black tea flakes and dry extract show additional sharp line attributed to semiquinone radical. The origins of the paramagnetic species in black tea are defined and discussed. Effect of humidity and heat are investigated. It is observed that dry extract of black tea melts at 100 °C and the semiquinone radical lives up to 140 °C while Mn 2+ sextet disappears just above 100 °C in tea extract. Natural and synthetics sweeteners have different effects on the paramagnetic centers. White sugar (sucrose) quenches the Mn 2+ and semiquinone lines in black tea EPR spectrum, and glucose, fructose, lactose and maltose quench Fe 3+ line while synthetic sweeteners acesulfam potassium, aspartame and sodium saccharine do not have any effect on paramagnetic species in tea.

  16. Thermal evolution of nitrate precursors for processing of lanthanide perovskites

    Directory of Open Access Journals (Sweden)

    Kozhukharov, V. S.

    1998-12-01

    Full Text Available Studies on thermal decomposition of ceramic powder with a general formula of (La1-x Ba x (Co0.8 Fe0.2O3 have been achieved. Precursors as nitrate solutions with additive of EDTA as complexion agent are used for powder processing. The black powders obtained are dried and their thermal evolution up to 1000ºC has been investigated by Differential Thermal Analysis. The powders was analyzed by EDX and ICP- AES, as well. It was established that the powder compositions are very close to the nominal one. The resulting DTA, TA, TG and DTG curves are analyzed as function of the composition and heating rate applied. At polythermal scanning regime three regions the powder thermal evolution are discussed. The correlation dependence has been examined for both Sr- and Ba- doped multicomponent lanthanide samples. The multicomponent nature of the samples have been shown on the base of the thermal treatment applied and XRD phase control carried out.

    Se han realizado estudios sobre la descomposición térmica de polvos cerámicos de fórmula general (La1-x Ba x (Co0.8 Fe0.2O3. Se utilizaron como precursores soluciones de nitratos con EDTA como agente acomplejante. La evolución térmica del polvo negro obtenido se estudió hasta la temperatura de 1000 ºC por medio de análisis térmico diferencial. Los polvos se analizaron así mismo por EDX e ICP-A ES. Se estableció que la composición de los polvos esta muy próxima a la composición nominal. Se distingue tres regímenes en la evolución térmica. Se examina la dependencia con el contenido en lantanidas multicomponentes de pulsos con Sr y Ba. La naturaleza multicomponente se ha mostrado sobre la base del tratamiento térmico empleado y el análisis de las fases cristalinas.

  17. Structural investigation of the complexation of uranyl and lanthanide ions by CMPO-functionalized calixarenes

    International Nuclear Information System (INIS)

    Cherfa, S.

    1998-12-01

    A way to reduce the volume of nuclear wastes is to make a simultaneous extraction of actinides and lanthanides for their ulterior separation. Historically, the two first series of extractants used for the reprocessing of these wastes are the phosphine oxides and the CMPO (carbamoyl methyl phosphine oxide). In order to better know the type of complexes formed during the extraction, have been carried out structural studies concerning these two series (uranyl complexes and lanthanide nitrates). These studies have been carried out by X-ray diffraction on monocrystals. More recently, a new series of extracting molecules of lanthanides (III) and actinides (III) have been developed. It has been shown that in functionalizing an organic macrocycle of calixarene type (cyclic oligomer resulting of the poly-condensation of phenolic units) by a ligand of CMPO type, the extracting power of these molecules in terms of yield and selectivity towards the lighter lanthanides was superior to those of the CMPO alone. This study, carried out by X-ray diffraction on monocrystals of complexes formed between these ligands calix[4]arenes-CMPO (with 4 phenolic units) with uranyl and lanthanides nitrates, has allowed to define the type of the formed complexes, that is to say to establish the stoichiometry and the coordination mode (monodentate or bidentate) of the CMPO functions. These different steps of characterization have allowed too to determine the correlations existing between the complexes structures in the one hand and the selectivity and the exacerbation of the extracting power measured in liquid phase on the other hand. (O.M.)

  18. 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.)

  19. Synthesis, magnetic and spectral studies of lanthanide(III) chloride complexes of hydrazones of isonicotinic acid hydrazide

    International Nuclear Information System (INIS)

    Agarwal, R.K.; Agarwal, Himanshu; Prasad, Ram

    1996-01-01

    The synthesis, magnetic and spectral properties of trivalent lanthanide chlorides with N-isonicotinamidobenzalaldimine (INH-BENZ), N-isonicotinamidoanisalaldimine (INH-ANSL) and N-isonicotinamido-p-dimethylaminobenzalaldimine (INH-PDAB) are described. 13 refs., 2 tabs

  20. Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding.

    Science.gov (United States)

    Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

    2011-06-01

    Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented.

  1. Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding

    International Nuclear Information System (INIS)

    Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

    2011-01-01

    Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented. (orig.)

  2. NMR study of heteroligand lanthanide complexes. Structure and stoichiometry of chelates of cerium subgroup with 18-member polyethers

    International Nuclear Information System (INIS)

    Bajbalov, S.P.; Kriger, Yu.G.

    1993-01-01

    Different ligand complexes of lanthanides were studied by the method of 1 H NMR, the results being presented. The literature data on the study of complexes of the class in solution were generalized. Detection of lanthanide-induced splitting of group CH 2 diastereotopic proton signals of macrocyclic polyethers in the complexes is enough to identify kinetically stable complexes, having inclusive type structure. 16 refs., 2 figs., 2 tabs

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Actinide-lanthanide separation by bipyridyl-based ligands. DFT calculations and experimental results

    International Nuclear Information System (INIS)

    Borisova, Nataliya E.; Eroshkina, Elizaveta A.; Korotkov, Leonid A.; Ustynyuk, Yuri A.; Alyapyshev, Mikhail Yu.; Eliseev, Ivan I.; Babain, Vasily A.

    2011-01-01

    In order to gain insights into effect of substituents on selectivity of Am/Eu separation, the synthesis and extractions tests were undertaken on the series of bipyridyl-based ligands (amides of 2,2'-bipyridyl-6,6'-dicarboxylic acid: L Ph - N,N'-diethyl-N,N'-diphenyl amide; L Bu2 - tetrabutyl amide; L Oct2 - tetraoctyl amide; L 3FPh - N,N'-diethyl-N,N'-bis-(3-fluorophenyl) amide; as well as N,N'-diethyl-N,N'-diphenyl amide of 4,4'-dibrom-2,2'-bipyridyl-6,6'-dicarboxylic acid and N,N'-diethyl-N,N'-diphenyl amide of 4,4'-dinitro-2,2'-bipyridyl-6,6'-dicarboxylic acid) as well as structure and stability of their complexes with lanthanides and actinides were studied. The extraction tests were performed for Am, lanthanide series and transition metals in polar diluents in presence of chlorinated cobalt dicarbolide and have shown high distribution coefficients for Am. Also was found that the type of substituents on amidic nitrogen exerts great influence on the extraction of light lanthanides. For understanding of the nature of this effect we made QC-calculations at DFT level, binding constants determination and X-Ray structure determination of the complexes. The UV/VIS titration performed show that the composition of all complexes of the amides with lanthanides in solution is 1:1. In spite of the binding constants are high (lgβ about 6-7 in acetonitrile solution), lanthanide ions have binding constants with the same order of magnitude for dialkyl substituted extractants. The X-Ray structures of the complexes of bipyridyl-based amides show the composition of 1:1 and the coordination number of the ions being 10. The DFT optimized structures of the compounds are in good agreement with that obtained by X-Ray. The gas phase affinity of the amides to lanthanides shows strong correlation with the distribution ratios. We can infer that the bipyridyl-based amides form complexes with metal nitrates which have similar structure in solid and gas phases and in solution, and the DFT

  8. Paramagnetism and magnetic relaxation in melt-textured grown GdBa2Cu3O6+y

    International Nuclear Information System (INIS)

    Qin, M.J.; Fu, X.K.; Ren, H.T.

    1996-01-01

    Magnetic measurements have been performed on a melt-textured grown (MTG) GdBa 2 Cu 3 O 6+y sample. Because of the paramagnetism of the Gd 3+ ions, the magnetization relaxation rate is increased by a factor of 4πχ. The effect of paramagnetism on the U(J) relationship of the sample has also been discussed. At the end, we extraxted the U(J) relationship based on the field sweep rate H, which is in agreement with the one after corrections for paramagnetism. (orig.)

  9. Fermi Surfaces in the Antiferromagnetic, Paramagnetic and Polarized Paramagnetic States of CeRh2Si2 Compared with Quantum Oscillation Experiments

    Science.gov (United States)

    Pourret, Alexandre; Suzuki, Michi-To; Palaccio Morales, Alexandra; Seyfarth, Gabriel; Knebel, Georg; Aoki, Dai; Flouquet, Jacques

    2017-08-01

    The large quantum oscillations observed in the thermoelectric power in the antiferromagnetic (AF) state of the heavy-fermion compound CeRh2Si2 disappear suddenly when entering in the polarized paramagnetic (PPM) state at Hc ˜ 26.5 T, indicating an abrupt reconstruction of the Fermi surface. The electronic band structure was calculated using [LDA+U] for the AF state taking the correct magnetic structure into account, for the PPM state, and for the paramagnetic state (PM). Different Fermi surfaces were obtained for the AF, PM, and PPM states. Due to band folding, a large number of branches was expected and observed in the AF state. The LDA+U calculation was compared with the previous LDA calculations. Furthermore, we compared both calculations with previously published de Haas-van Alphen experiments. The better agreement with the LDA approach suggests that above the critical pressure pc CeRh2Si2 enters in a mixed-valence state. In the PPM state under a high magnetic field, the 4f contribution at the Fermi level EF drops significantly compared with that in the PM state, and the 4f electrons contribute only weakly to the Fermi surface in our approach.

  10. Thermally stimulated luminescence and electron paramagnetic resonance studies on uranium doped calcium phosphate

    CERN Document Server

    Natarajan, V; Veeraraghavan, R; Sastry, M D

    2003-01-01

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies on uranium doped calcium phosphate yielded mechanistic information on the observed glow peaks at 365, 410 and 450 K. TSL spectral studies of the glow peaks showed that UO sub 2 sup 2 sup + acts as the luminescent center. Electron paramagnetic resonance studies on gamma-irradiated samples revealed that the predominant radiation induced centers are H sup 0 , PO sub 4 sup 2 sup - , PO sub 3 sup 2 sup - and O sup - ion. Studies on the temperature dependence studies of the EPR spectra of samples annealed to different temperatures indicate the role of H sup 0 and PO sub 4 sup 2 sup - ions in the main glow peak at 410 K.

  11. Nuclear and solid state investigations for the non-cubic paramagnetic system europium in samarium

    International Nuclear Information System (INIS)

    Boehm, R.

    1979-01-01

    By means of the time-differential perturbed angular gamma distribution after a nuclear reaction (TDPAD) the g-values of the isomer 1 1/2 - states are measured in 145 Eu and 147 Eu in the host metal Sm. The results are g ( 145 Eu) = + 1.356 + 0.008 g ( 147 Eu) = + 1.28 +- 0.01. The temperature dependence of the paramagnetic correction β obeys a Curie-Weiss law β = 1 + C/CT-, with C = -(50 +- 2) K and THETA = -(29 +- 5) K between 90 K and 1000 K, for both systems, 145 EU Sm and 147 Eu Sm. For room temperature the quadrupole coupling constant νsub(Q) is determined for 145 Eu Sm for the 1 1/2 - state: νsub(Q) = (12.5 +- 0.5) MHz and the paramagnetic relaxation time tausub(p) >= 1 μs. The g values are investigated also theoretically. (BHO)

  12. Electron paramagnetic resonance investigation of polycrystalline CaCu3Ti4O12

    International Nuclear Information System (INIS)

    Mozzati, Maria Cristina; Azzoni, Carlo Bruno; Capsoni, Doretta; Bini, Marcella; Massarotti, Vincenzo

    2003-01-01

    Electron paramagnetic resonance (EPR) measurements on pure polycrystalline CaCu 3 Ti 4 O 12 have been performed and are discussed within a crystal-field approach. A symmetric signal centred at g = 2.15 is observed for T>25 K, with no evidence of hyperfine structure. At this temperature an antiferromagnetic transition is observed as confirmed by static magnetization data. Cu defective and 2% doped (V, Cr, Mn, La) samples were also prepared and considered, mainly to understand the nature of the observed paramagnetic centre. Substitutions in the octahedral sites, causing variations of the configuration in CuO 4 -TiO 6 -CuO 4 complexes, change the magnetic and EPR features. To justify the EPR response a strong copper-hole delocalization is suggested

  13. Correlation between temperature dependence of elastic moduli and Debye temperature of paramagnetic metal

    International Nuclear Information System (INIS)

    Bodryakov, V.Yu.; Povzner, A.A.

    2000-01-01

    The correlation between the temperature dependence of elastic moduli and the Debye temperature of paramagnetic metal is analyzed in neglect of the temperature dependence of the Poison coefficient σ within the frames of the Debye-Grueneisen presentations. It is shown, that namely the temperature dependence of the elastic moduli determines primarily the temperature dependence of the Debye temperature Θ(T). On the other hand, the temperature dependence Θ(T) very weakly effects the temperature dependence of the elastic moduli. The later made it possible to formulate the self-consistent approach to calculation of the elastic moduli temperature dependence. The numerical estimates of this dependence parameters are conducted by the example of the all around compression modulus of the paramagnetic lutetium [ru

  14. Temperature dependence of Q-band electron paramagnetic resonance spectra of nitrosyl heme proteins

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Marco; Wajnberg, Eliane; Bemski, George

    1997-11-01

    The Q-band (35 GHz) electron paramagnetic resonance (EPR) spectra of nitrosyl hemoglobin (Hb N O) and nitrosyl myoglobin (Mb NO) were studied as a function of temperature between 19 K and 200 K. The spectra of both heme proteins show classes of variations as a function of temperature. The first one has previously been associated with the existence of two paramagnetic species, one with rhombic and the other with axial symmetry. The second one manifests itself in changes in the g-factors and linewidths of each species. These changes are correlated with the conformational substates model and associate the variations of g-values with changes in the angle of the N(his)-Fe-N (NO) bond in the rhombic species and with changes in the distance between Fe and N of the proximal (F8) histidine in the axial species. (author) 24 refs., 6 figs.

  15. Study of the ferrimagnetic and paramagnetic phases of magnetite measured by multiple neutron diffraction

    International Nuclear Information System (INIS)

    Mazzocchi, V.L.

    1992-01-01

    Structural parameters of the ferrimagnetic and paramagnetic phases of magnetite have been refined from neutron multiple diffraction data. Experimental multiple diffraction patterns used in the refinement, were obtained by measuring the 111 primary reflection of a natural single crystal of this compound, at room temperature for the ferrimagnetic phase and 703 0 C for the paramagnetic phase. Corresponding theoretical patterns for both phases have been calculated by the program MULTI which uses the iterative method for the intensity calculations in neutron multiple diffraction. In this method intensities are calculated as Taylor series expansions summed up to a order sufficient for a good approximation. A step by step process has been used in the refinements according to the parameter-shift method. Both isotropic and anisotropic thermal parameters were used in the calculation of the temperature factor. (author)

  16. Paramagnetic properties of the (U1-xTbx)Co2Ge2 solid solutions

    International Nuclear Information System (INIS)

    Kuznietz, Moshe; Pinto, Haim; Ettedgui, Hanania

    1995-01-01

    Polycrystalline (U 1-x Tb x )Co 2 Ge 2 solid solutions have the ThCr 2 Si 2 -type crystal structure and order antiferromagnetically. AC-susceptibility at 80-295 K yields paramagnetic Curie temperatures θ=-350±50, -15±5, -50±15, -12±5, and -80±5 K, and effective magnetic moments μ eff =4.5, 5.9, 7.3, 8.5, and 12.0 (±0.5)μ B , for samples with x=0, 0.25, 0.50, 0.75 and 1, respectively. The high μ eff values are related to occurrence of paramagnetic moments on U, Tb and Co, of which only U and Tb moments order magnetically. ((orig.))

  17. Lanthanides and actinides extraction by calixarenes containing CMPO groups; Extraction des lanthanides et des actinides au moyen de calixarenes portant des groupements CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Carrera, A

    2001-07-01

    In the framework of the French program SPIN concerning the radioactive waste management, researches are performed to develop processes allowing the separation of long-lived radioisotopes in order to their transmutation or their specific conditioning. These studies deal with the extraction and the separation of trivalent lanthanides and actinides in acid solution. Many systems ''calixarene-diluent-aqueous phase'' are examined by extraction liquid-liquid and membrane transport. The extraction efficiency and the selectivity of the synthesized calixarene-CMPO and of the CMPO are compared with these cations, as the nitric acid extraction by these molecules. (A.L.B.)

  18. A sextupole-magnet as variable velocity selector for paramagnetic atomic beams in the thermal range

    International Nuclear Information System (INIS)

    Spindler, G.; Ebinghaus, H.; Steffens, E.

    1974-01-01

    The possibility of employing a sextupole-magnet as a velocity selector on account of its velocity dependent focusing properties for paramagnetic atomic beams is investigated. In comparison with a traditional velocity selector with rotating disks, a sextupole-magnet as velocity selector has the advantage of additional focusing and polarizing the atomic beam. Moreover it suppresses polymer molecules without an effective magnetic momentum of the electronic shell

  19. Aberrant paramagnetic signals outside the tumor volume on routine surveillance MRI of brain tumor patients.

    Science.gov (United States)

    Yust-Katz, Shlomit; Inbar, Edna; Michaeli, Natalia; Limon, Dror; Siegal, Tali

    2017-09-01

    Late complications of cerebral radiation therapy (RT) involve vascular injury with acquired cavernous malformation, telangiectasias and damage to vascular walls which are well recognized in children. Its incidence in adults is unknown. Blood products and iron deposition that accompany vascular injury create paramagnetic effects on MRI. This study retrospectively investigated the frequency of paramagnetic lesions on routine surveillance MRI of adult brain tumor patients. MRI studies of 115 brain tumor patients were reviewed. Only studies containing sequences of either susceptibility weighted images or gradient echo or blood oxygenation level dependent imaging were included. Lesions inside the tumor volume were not considered. 68 studies fulfilled the above criteria and included 48 patients with previous RT (35 followed for >2 years and 13 for 1 year) and 20 patients who were not treated with RT. The median age at time of irradiation was 47 years. Aberrant paramagnetic lesions were found in 23/35 (65%) patients followed for >2 years after RT and in only 1/13 (8%) patients followed for 1-year after radiation (p = 0.03). The 1-year follow-up group did not differ from the control group [2/20 (9%)]. Most lesions were within the radiation field and none of the patients had related symptomatology. The number and incidence of these lesions increased with time and amounted to 75% over 3 years post RT. MRI paramagnetic signal aberrations are common findings in adult brain tumor patients that evolve over time after RT. The clinical significance of these lesions needs further investigation.

  20. First-principles calculation of the magnetic properties of paramagnetic fcc iron

    International Nuclear Information System (INIS)

    Johnson, D.D.; Gyorffy, B.L.; Pinski, F.J.; Staunton, J.; Stocks, G.M.

    1985-01-01

    Using the disordered local moment picture of itinerant magnetism, we present calculations of the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state. These calculations are based on the parameter-free, first principles approach of local spin density functional theory and the coherent potential approximation is used to treat the disorder associated with the random orientation of the local moments