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1.
Results of measurements of the yield of Nd 3+ radioluminescence photons in inorganic laser liquids POCl 3-MCl n- 235UO 2 2+ -Nd 3+ (M = Ti, Zr, Sn, or Sb) during homogeneous excitation by uranium α-particles are presented. It was found that the intensity of radioluminescence corresponding to the 4 F 3/2 → 4 I 11/2 transition in neodymium ions depends on the solvent composition. Data on the radiation-chemical yield, G, of excited neodymium ions in the POCl 3-MCl n- 235UO 2 2+ -Nd 3+ (M = Ti, Zr, Sn, or Sb) system were obtained. At a neodymium concentration of 0.25 mol/l, the values of G for the excited ions were 0.60 ± 0.10, 0.84 ± 0.10, 1.20 ± 0.10, and 1.64 ± 0.16 ion/100 eV in solutions with TiCl 4, ZrCl 4, SnCl 4, and SbCl 5, respectively. The maximum yields of excited ions estimated at G = 1.68 ± 0.10 and 2.20 ± 0.24 ion/100 eV were obtained for the solutions with SnCl 4 and SbCl 5, respectively, at neodymium ion concentrations above 0.4 mol/l. 相似文献
2.
Results of studying the spectral and luminescent properties of Eu 3+ ions upon homogeneous excitation of POCl 3–SnCl 4– -UO 2+
2–Eu 3+ and D 2O– 235UO 2+
2–Eu 3+ solutions by -particles are presented. It was found that the radioluminescence intensity of Eu 3+ ions in both solvents increases proportionally to the energy input by -particles. The yield of radioluminescence photons from europium ions in the POCl 3–SnCl 4–UO 2+
2–Eu 3+ solutions is more than nine times as high as that in D 2O–UO 2+
2–Eu 3+. The radiation-chemical yields of excited 5
D
0 states of Eu 3+ ions are 0.74 ± 0.07 and 0.18 ± 0.02 ions/100 eV in POCl 3–SnCl 4–UO 2+
2–Eu 3+ and D 2O–UO 2+
2–Eu 3+ solutions, respectively. 相似文献
3.
Samples of POCl 3-SnCl 4- 235UO 2-Dy 3+ solutions have been prepared to investigate conversion of energy of heavy charged particles into optical radiation. Experimental data on radioluminescent characteristics of Dy 3+ upon homogenous excitation of solutions by uranium α-radiation have been obtained. The efficiency of conversion of the energy of uranium α-particles into light energy depends on the Dy 3+ concentration and the Dy 3+ luminescence lifetime τ. At [Dy 3+] = 0.2 mol/L and τ = 550 μs, the conversion efficiency is 0.12 ± 0.01% for the luminescent transition 4F 9/2 → 6H 13/2 (λ max = 574 nm) or 0.20 ± 0.01% for the visible and near IR regions of Dy 3+ luminescence. 相似文献
4.
In this work, we present for the first time the spectroscopic properties of perovskite nanocrystals CaTiO 3: Nd 3+, measured at room and liquid nitrogen temperature. Samples were prepared by the sol–gel method and annealed at 700 and 1000 °C. The concentration of Nd 3+ ranged from 0.5% to 5%. Average nanocrystallite size primarily depends on the annealed temperature and is about 25 and 50 nm for 700 and 1000 °C, respectively. The absorption, emission and excitation spectra (monitored at 1078 nm) as well as the decay time profile of the emission from the 4F3/2 energy level of Nd 3+ are obtained. The increasing amount of Nd 3+ ions decreases the lifetime of the 4F3/2 level and that changes from 146 μs for 0.5% to 50 μs for 5% of Nd 3+ concentration. The strongest emission was observed at two regions: 1050–1120 nm and 865–930 nm and was assigned to the 4F3/2→ 4I11/2 and 4F3/2→ 4I9/2 transitions, respectively. The spectroscopic quality parameter of neodymium in the CaTiO 3 lattice has been calculated from the emission spectra. The influence of luminescent properties depending on the annealing temperature and concentration of neodymium ions is discussed. 相似文献
5.
在四氯酸锌离子诱导下,五元瓜环能与钕离子构筑形成二维配合超分子自组装。在HCl介质中,Zn 2+容易形成四氯酸锌离子,在其诱导作用下,钕离子和五元瓜环端口羰基氧直接配位形成二维超分子自组装体。结果表明锌离子作为一种结构导向剂在形成瓜环基超分子自组装体中起到重要作用。 相似文献
6.
There is a lack of information on electronic spectra of divalent neodymium, and thus the synthesis and characterization of Nd 2+ systems is now reported. Stabilization of neodymium is observed in a chloride host, which importantly has been accomplished with Nd ions introduced in a divalent state during synthesis, unlike by γ‐irradiation of Nd 3+ system employed previously. This method yields good‐quality SrCl 2:Nd 2+ single crystals. For the first time the electronic absorption spectra of Nd 2+ doped in SrCl 2 have been recorded with high resolution at liquid helium temperature (4.2 K). Identification of the absorption bands occurring in the spectral range of 5000–40 000 cm −1 (2000–250 nm) has been achieved and their tentative assignment proposed. This uniquely detailed Nd 2+ absorption spectrum provides basis for fingerprinting method enabling identification of the presence of Nd 2+ ions in future spectra as well as in existing but as‐yet not fully resolved spectra. 相似文献
7.
We have investigated the self‐assembly of three luminescent species in CH 3CN/CH 2Cl 2, namely: 1) a polylysin dendrimer ( D ) composed of 21 aliphatic amide units and 24 green luminescent dansyl chromophores at the periphery, 2) a molecular clip ( C ) with two blue luminescent anthracene sidewalls and a benzene bridging unit that bears two sulfate groups in the para position, and 3) a near infrared (NIR)‐emitting Nd 3+ ion. For purposes of comparison, analogous systems have also been investigated in which Gd 3+ replaced Nd 3+. The dendrimer and the clip can bind Nd 3+ ions with formation of [ D? 2 Nd 3+] and [ C? Nd 3+] complexes, in which energy transfer from dansyl and, respectively, anthracene to Nd 3+ ion takes place with 65 and 8 % efficiency, in air‐equilibrated solution. In the case of [ C? Nd 3+], the energy‐transfer efficiency is quenched by dioxygen, thereby showing that the energy donor is the lowest triplet excited state of anthracene. In [ D? 2 Nd 3+] the intrinsic emission efficiency of Nd 3+ is much higher (ca. 5 times) than in [ C? Nd 3+] because of a better protection of the excited lanthanide ion towards nonradiative deactivation caused by interaction with solvent molecules. By mixing solutions of D , Nd 3+, and C with proper concentrations, a supramolecular structure with five components of three different species, [ D? 2 Nd 3+ ? 2 C ], is formed. The excitation light absorbed by the clips is transferred with 100 % efficiency to the dansyl units of the dendrimer and then to the Nd 3+ ions with 65 % efficiency either in the presence or absence of dioxygen. These results show that the [ D? 2 Nd 3+ ? 2 C ] complex is able to efficiently harvest UV light by the 24 dansyl units of the dendrimer and the four anthracene chromophores of the two clips, and efficiently transfer it to the encapsulated Nd 3+ ions that emit in the NIR spectral region. 相似文献
8.
The sol-gel technology has been applied to obtain SiO 2 spheres of submicron size. The spheres have been doped with YAG:Nd 3+ nanocrystallites. The nanocrystallites have been obtained from aqueous solutions of citric acid, yttrium, aluminum and neodymium chlorides. The obtained gels have been heated up to 800°C. Emission spectra as well as the excited state lifetimes have been measured at room and liquid nitrogen temperatures. The structural characterization has been performed by means of transmission and scanning electron microscopies (TEM, SEM) and powder diffraction (XRD) measurements. We have observed that the YAG:Nd 3+ nanocrystallites demonstrate pronounced dependence of the emission intensities on the excitation power as compared to the YAG:Nd 3+ crystallites embedded into the submicron SiO 2 spheres. The results suggest that silica spheres/YAG:Nd 3+ composites are expected to be good hosts for microlaser systems. 相似文献
9.
A parametric analysis of the Stark-split spectra of Nd 3+ in frozen dilute aqueous solutions of neodymium chloride has been carried out.The similarity of the spectra of Nd 3+ in frozen dilute solutions and in crystals, where the ion is nine-fold coordinated and of approximate D 3h symmetry (Nd 3+: LaCl 3, neodymium ethylsulfate and bromate), was used to obtain initial parameter values. Simultaneous diagonalization of the free ion and crystal field hamiltonians resulted in a r.m.s. deviation σ of 11 cm ?1 for 50 levels. The resulting crystal field parameters are B20 = 278 ± 19, B40 = ?201 ± 39, Bb0 = ?946 ± 55 and B66 = 663 ± 43 cm ?1. Selection rules for D 3h are approximately obeyed. The small value of σ, the number of levels accounted for and the fact that the final parameters are not very different from those in the crystals indicate a nine-fold coordination of approximate D 3h symmetry for Nd 3+ in frozen aqueous solutions. The spectra of liquid solutions show by their similarity to the spectra of frozen solutions that the same surroundings exist in the liquid. 相似文献
10.
Complexes of UO 2
2+, Ce 3+ and Nd 3+ (M) with acetohydroxamic acid (AHA or L) in an aqueous solution have been investigated by the pH-spectral titration method
at 25 °C in an aqueous medium of 1.0 M NaClO 4 ionic strength. Cerium(III) and neodymium(III) form [ML] 2+, [ML 2] +, [ML 3] complexes with acetohydroxamic acid, while in case of UO 2
2+ form [UO 2L] +, [UO 2L 2] complexes with acetohydroxamic acid. Data processing with SQUAD program calculates the best values for the stability constants
from pH-spectrophotometric titration data. The protonation constant obtained was pK 1 = 9.15 ± 0.04 at 25 °C. The stability constants for acetohydroxamic acid with UO 2
2+, Ce 3+ and Nd 3+ were β 1 = 7.22 ± 0.011, β 2 = 14.89 ± 0.018 for UO 2
2+ and β 1 = 5.05 ± 0.062, β 2 = 10.60 ± 0.076, β 3 = 16.23 ± 0.088 for Ce 3+ and β 1 = 5.90 ± 0.028, β 2 = 12.22 ± 0.038, β 3 = 18.58 ± 0.042 for Nd 3+, respectively. 相似文献
12.
采用原位显微Raman光谱和 18O同位素示踪技术,以325 nm激光为激发光源,对立方Nd 2O 3上过氧物种的光诱导生成过程进行了详细表征,进一步证实过氧源于分子氧对晶格氧的氧化反应. 结果还表明,325 nm激光在室温下即可诱导过氧的生成,在实验条件下,生成的过氧物种可与Nd 2O 3的晶格氧发生快速的氧交换反应,位于Nd 2O 3体相的晶格氧也可迁移至样品表层进而参与过氧的生成. 325 nm激光照射有助于促进晶格氧的迁移以及晶格氧与分子氧之间的氧交换反应. 相似文献
13.
Single crystals of Nd 5(AsO 3) 4Cl 3 (monoclinic, P2/ n, Z = 2, a = 1026.0(1), b = 543.35(3), c = 1400.2(1) pm, β = 93.48(1)°) were obtained from the reaction of Nd 2O 3, As 2O 3 and NaCl in a sealed silica ampoule. In the crystal structure the Nd 3+ ions are linked by AsO 33? groups into layers that alternate with layers of Cl ? ions. Two of the three crystallographically different Nd 3+ ions are coordinated by eight oxygen atoms, the third one has four oxygen and four chlorine atoms as neighbours. 相似文献
14.
Studies on the separation of calcium and neodymium ions by using ethylenediaminetetraacetic acid (H4EDTA) as a complexing agent were performed. This research was undertaken due to the possibility of H4EDTA applying to isolate rare earth elements from the solution after acidic leaching of phosphogypsum, and because of the similarity of coordination properties of calcium and lanthanides ions. The experiment was carried out in model systems containing Ca2+ and Nd3+ ions in hydrochloric or sulphuric acid. The content of calcium and neodymium metals, phase composition and thermal behaviour of the obtained products were determined by ICP-OES, FTIR, XRD and TG/DTA techniques. During the separation process, the precipitates of a light pink colour were obtained. The obtained results show that the neodymium ethylenediaminetetraacetate has been successfully formed and that the isolation of neodymium ions was more efficient in chloride medium. The precipitate included 72.2 and 3.9% of the starting amount of neodymium and calcium used in the experiment, respectively. However, in sulphates medium, these amounts were equal to 73.8 and 53.5%, respectively. Moreover, the obtained powder was polluted with sulphates. The addition of the EDTA in an excess (15%) contributed only to an increase in calcium content in the complex. 相似文献
15.
Nd 3+-doped precursor glass in the K 2O–SiO 2–Y 2O 3–Al 2O 3 (KSYA) system was prepared by the melt-quench technique. The transparent Y 3Al 5O 12 (YAG) glass–ceramics were derived from this glass by a controlled crystallization process at 750 °C for 5–100 h. The formation of YAG crystal phase, size and morphology with progress of heat-treatment was examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transformed infrared reflectance spectroscopy (FT-IRRS). The crystallite sizes obtained from XRD are found to increase with heat-treatment time and vary in the range 25–40 nm. The measured photoluminescence spectra have exhibited emission transitions of 4F 3/2 → 4I J ( J = 9/2, 11/2 and 13/2) from Nd 3+ ions upon excitation at 829 nm. It is observed that the photoluminescence intensity and excited state lifetime of Nd 3+ ions decrease with increase in heat-treatment time. The present study indicates that the incorporation of Nd 3+ ions into YAG crystal lattice enhance the fluorescence performance of the glass–ceramic nanocomposites. 相似文献
16.
In the present work the uranyl hexacyanoferrate (K 2UO 2[Fe(CN) 6]) is deposited on the palladized aluminum (Pd-Al) electrode from a
\text UO22 + + \text Fe( \text CN ) 6 - 3 {\text{UO}}_{2}^{2 + } + {\text{Fe}}\left( {\text{CN}} \right)_{6}^{ - 3} solution. Then the anodic stripping chronopotentiometry (ASCP) was used to strip the K 2UO 2[Fe(CN) 6] from the Pd-Al surface. The operational conditions including: pH, K 3Fe(CN) 6 concentration, deposition potential, deposition time and stripping current were optimized. The ASCP calibration graph was
linear in concentration range 10–460 μM. of
\text UO22 + {\text{UO}}_{2}^{2 + } and the detection limit was 8.5 μM. The interference of some concomitant ions during the deposition process of K 2UO 2[Fe(CN) 6] was studied. The proposed method was successfully applied for analysis of some uranium mineral ores. 相似文献
17.
A new bidentate nitrogen donor complexing agent that combines pyridine and triazole functional groups, 2-((4-phenyl-1 H-1,2,3-triazol-1-yl)methyl)pyridine (PTMP), has been synthesized. The strength of its complexes with trivalent americium (Am 3+) and neodymium (Nd 3+) in anhydrous methanol has been evaluated using spectrophotometric techniques. The purpose of this investigation is to assess
this ligand (as representative of a class of similarly structured species) as a possible model compound for the challenging
separation of trivalent actinides from lanthanides. This separation, important in the development of advanced nuclear fuel
cycles, is best achieved through the agency of multidentate chelating agents containing some number of nitrogen or sulfur
donor groups. To evaluate the relative strength of the bidentate complexes, the derived constants are compared to those of
the same metal ions with 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen), and 2-pyridin-2-yl-1 H-benzimidazole (PBIm). At issue is the relative affinity of the triazole moiety for trivalent f element ions. For all ligands,
the derived stability constants are higher for Am 3+ than Nd 3+. In the case of Am 3+ complexes with phen and PBIm, the presence of 1:2 (AmL 2) species is indicated. Possible separations are suggested based on the relative stability and stoichiometry of the Am 3+ and Nd 3+ complexes. It can be noted that the 1,2,3-triazolyl group imparts a potentially useful selectivity for trivalent actinides
(An(III)) over trivalent lanthanides (Ln(III)), though the attainment of higher complex stoichiometries in actinide compared
with lanthanide complexes may be an important driver for developing successful separations. 相似文献
18.
The magnetic susceptibility of the semiconducting lanthanide cuprates Nd 2CuO 4, Pr 2CuO 4, Eu 2CuO 4, and Sm 2CuO 4 has been measured in the range 4–300 K. Below 300 K, the Cu 2+ ions are ordered antiferromagnetically in the CuO 2 planes of these compounds, and the exchange interactions involving the Ln3+ ions are relatively weak. The suceptibility of the Ln3+ ions obeys the Curie-Weiss law at elevated temperatures, but deviations from this law occur at lower temperatures. An attempt is made to account for these deviations by fitting theoretical expressions for the susceptibility of isolated Ln3+ ions under the influence of a cubic crystal field to the experimental data. Excellent agreement is obtained for Nd 3+ and Eu 3+ over the entire temperature range and for Pr 3+ and Sm 3+ at elevated temperatures. Deviations at lower temperatures for the latter two ions may be due to structural changes, exchange interactions involving the Ln3+ ions, or possibly oxygen nonstoichiometry. The susceptibility parameters derived by fitting the theoretical expressions to the experimental data are also discussed. It is concluded that these compounds form an interesting new series of planar Cu 2+-ion antiferromagnets. 相似文献
19.
On the Dimorphism of Nd 3Cl[SiO 4] 2 On reacting NdCl 3, Nd 2O 3, and SiO 2 (molar ratio: 1 : 4 : 6) at 850 °C in evacuated silica tubes, pale violet, hydrolysis resistant neodymium(III) chloride ortho‐silicate Nd 3Cl[SiO 4] 2 can be obtained within seven days. If equimolar amounts of NaCl are added as flux, rod‐ or platelet‐shaped, transparent single crystals of two modifications accumulate simultaneously. The one with the higher density (A‐Nd 3Cl[SiO 4] 2) crystallizes monoclinically (C2/c, no. 15; a = 1416.6(1), b = 638.79(6), c = 872.21(9) pm, β = 98.403(7)°; V m = 117.55 cm 3/mol, Z = 4), whereas the one with the lower density (B‐Nd 3Cl[SiO 4] 2) exhibits orthorhombic symmetry (Pnma, no. 62; a = 709.36(7), b = 1815.7(2), c = 631.48(6) pm; V m = 122.45 cm 3/mol, Z = 4). Two crystallographically independent Nd 3+ cations exist in each of both crystal structures, which in the A type are surrounded by nine (1 Cl – + 8 O 2–) and ten (2 Cl – + 8 O 2–), whilst those in the B type by only two times eight (1 Cl – + 7 O 2– and 2 Cl – + 6 O 2–) anions, respectively. Thereby all oxygen atoms of both forms represent members of discrete ortho‐silicate tetrahedra ([SiO 4] 4–). Although both crystal structures are built of alternating anionic double layers {(Nd1) 2[SiO 4] 2} 2– and cationic single layers {(Nd2)Cl} 2+, there is a higher cross‐linkage of the building units in the A‐type lattice, where the cations are coordinated by three and four tetrahedra edges of ortho‐silicate anions, compared to only two times two of them in the B type. From this an about 4% higher density of Nd 3Cl[SiO 4] 2 results for the A‐type structure (D x = 5.55 g/cm 3) in comparison with B‐type Nd 3Cl[SiO 4] 2 (D x = 5.33 g/cm 3). 相似文献
20.
Abstract The optical absorption spectra of Nd 3+ ion in glutamic, L-aspartic and maleic acids in UV-VIS and NIR regions have been recorded. From the spectral data thus obtained, various spectroscopic parameters are evaluated. The radiative lifetimes (γR) and branching ratios (β) for the excited states of Nd 3+ ion in three acids have been computed. The relationship between the environment sensitive Judd-Ofelt parameter (ω 2) and the intensities of hypersensitive level ( 4G 5/2) is in good coincidence following the Judd-Ofelt theory. 相似文献
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