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1.
We have studied photoluminescence and thermoluminescence (PL and TL) in CaGa2Se4:Eu crystals in the temperature range 77–400 K. We have established that broadband photoluminescence with maximum at 571 nm
is due to intracenter transitions 4f6 5d–4f7 (8S7/2) of the Eu2+ ions. From the temperature dependence of the intensity (log I–103/T), we determined the activation energy (E
a = 0.04 eV) for thermal quenching of photoluminescence. From the thermoluminescence spectra, we determined the trap depths:
0.31, 0.44, 0.53, 0.59 eV. The lifetime of the excited state 4f6 5d of the Eu2+ ions in the CaGa2Se4 crystal found from the luminescence decay kinetics is 3.8 μsec.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 112–116, January–February, 2009. 相似文献
2.
Wen-Xian Li Yu-Shan Zheng Xiao-Jun Sun Xiao-Yan Shi Wen-Juan Chai Tie Ren 《Journal of fluorescence》2010,20(1):235-241
A ligand with double sulfinyl groups, naphthyl-naphthalinesulphonylpropyl sulfoxide(dinaphthyl disulfoxide, L), was synthesized
by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity,
coordination titration analysis, IR, TG-DTA, 1HNMR and UV spectra. The composition of these complexes, were RE2(ClO4)6·(L)5·nH2O (RE = La, Nd, Eu, Tb, Yb, n = 2 ∼ 6, L = C10H7SOC3H6SOC10H7). The fluorescent spectra illustrated that the Eu (III) complex had an excellent luminescence. It was supposed that the ligand
was benefited for transferring the energy from ligand to the excitation state energy level (5D0) of Eu (III). The Tb (III) complex displayed weak luminescence, which attributed to low energy transferring efficiency between
the average triplet state energy level of ligand and the excited state (5D4) of Tb (III). So the Eu (III) complex displayed a good antenna effect for luminescence. The phosphorescence spectra and the
relationship between fluorescence lifetime and fluorescence intensity were also discussed. 相似文献
3.
The position and momentum space information entropies of weakly interacting trapped atomic Bose–Einstein condensates and spin-polarized
trapped atomic Fermi gases at absolute zero temperature are evaluated. We find that sum of the position and momentum space
information entropies of these quantum systems containing N atoms confined in a D( ≤ 3)-dimensional harmonic trap has a universal form as St(D) = N(a D - b lnN) S_\mathrm{t}^{(D)} = N(a D - b \ln N) , where a ≃ 2.332 and b = 2 for interacting bosonic systems and a ≃ 1.982 and b = 1 for ideal fermionic systems. These results obey the entropic uncertainty relation given by Beckner, Bialynicki-Birula
and Myceilski. 相似文献
4.
Efficient room-temperature operation of 4
F
3/24
I
9/2 transitions in diode-end-pumped Nd:YAG lasers at 946 nm and 938.5 nm is reported. 7.0-W continuous-wave output power at 946 nm
and 3.9 W at 938.5 nm have been obtained. An analytical model has been developed for the quasi-three-level laser including
the influence of energy-transfer upconversion. Frequency doubling of these transitions in periodically poled KTP generated
blue light at 473 nm and 469 nm. Both single-pass extra-cavity as well as intracavity schemes have been investigated.
Received: 31 July 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +46-8/750-5430, E-mail: stefan.bjurshagen@acreo.se 相似文献
5.
The nuclear spectroscopic quadrupole moments for the πh9/25/2-, 1/2-[541] and the πh11/29/2-, 9/2-[514] isomeric states in 169Ta have been measured employing the time differential perturbed angular-distribution technique following the nuclear reaction
159Tb(16O, 6nγ)169Ta at beam energy 104 MeV. The ratio of the intrinsic quadrupole moments
has been derived as 1.87(13) from the measured quadrupole precession frequencies of the corresponding states. The model-independent
analysis of the equilibrium deformation indicates strong prolate- and oblate-driving nature of the 1/2-[541] and 9/2-[514] orbitals in 169,171Ta isotopes, respectively. 相似文献
6.
V. I. Gerasimova A. A. Antoshkov Yu. S. Zavorotny D. A. Lemenovskii 《Journal of Applied Spectroscopy》2012,79(2):203-210
Optical properties (photoluminescence and absorption) of Eu(bta)3(B) n (B = H2O or 1,10-phenanthroline) polycrystalline powders and fluoroacrylate polymers (FAPs) impregnated with these compounds using supercritical CO2 (SC CO2) were investigated. It was established that impregnation of Eu(bta)3phen into the FAPs using an SC CO2 solution was difficult to achieve. The type of B (ancillary ligand) and the polymer matrix were shown to influence the temperature quenching of photoluminescence of Eu3+ ions in the range 25–100°C. A comparative analysis of quantum yields (λex = 300 and 380 nm) and photoluminescence decay times (λex = 337.1 nm) for Eu(bta)3B n and for Eu(bta)3B n -doped FAPs was performed. 相似文献
7.
Spectroscopic properties of praseodymium ions-doped erbium oxalate (Er2(C2O4)3 · nH2O) crystals have been investigated. The crystals were grown by hydro silica gel method under suitable pH conditions and by
single diffusion method. The well-grown crystals are bright and transparent. The dark green colour of these crystals changes
with the variation of the concentrations of the dopant ions. The absorption spectra have been measured in the region 200–800
nm at room temperature. Judd–Ofelt intensity parameters for f–f transitions of the Pr3+ ions have been determined as Ω2 = 166.7, Ω4 = 1.103 and Ω6 = 2.898. Analyses of the absorption spectra also show a possible energy transfer from the host material to the dopant. 相似文献
8.
H. Schaaf U. Schmeling G. Werth 《Applied Physics A: Materials Science & Processing》1981,25(3):249-251
The spatial density distribution of Ba+ ions, confined in a rf quadrupole trap, has been measured by laser scanning across the trap. This allows to determine the
ion temperature, assuming thermal equilibrium. Under UHV conditions the average ion energy has been found to be one tenth
of the trap potential well depth. Collisions with He at pressures up to 5×10−6 mbar reduce the ion temperature by a factor of 3. 相似文献
9.
6-Hydroxy chromone-3-carbaldehyde-(4′-hydroxy) benzoyl hydrazone (L) and its Ln (III) complexes, [Ln = La, Nd, Eu and Tb]
have been prepared and characterized on the basis of elemental analyses, molar conductivities, mass spectra, 1H NMR, thermogravimety/differential thermal analysis (TG-DTA), UV-vis spectra, fluorescence spectra and IR spectra. The formula
of the complex is [Ln L·(NO3)2]·NO3. Spectrometric titration, ethidium bromide displacement experiments and viscosity measurements indicate that Eu (III) complex
bind with calf-thymus DNA, presumably via an intercalation mechanism. The intrinsic binding constant of Eu (III) with DNA
was 2.48 × 105 M−1 through fluorescence titration data. 相似文献
10.
Luteolin and apigenin, extracted from Reseda luteola L., were spectrophotometrically and fluorimetrically studied. The spectra were investigated as a function of pH in methanol/water
solutions (1/2, v/v) in the 2–12 pH range. The absorption spectra markedly shifted to the red by increasing the pH. Three acid–base dissociation
steps were detected for luteolin (pK
a = 6.9; 8.6; 10.3) and two for apigenin (pK
a = 6.6; 9.3). Fluorescence emission was very weak or undetectable (Φ
F < 10−4) in acidic solution, but increased in intensity with increasing the pH. Both molecules exhibited a great propensity towards
complex formation with metal ions, with association constants on the order of 105–107 for the first complexation step; in the presence of excess Al3+ ions, multiple equilibria were detected. A marked fluorescence enhancement was observed upon complexation with Al3+ ions (Φ
F ∼ 1 for luteolin and ∼10−2 for apigenin). 相似文献
11.
Luminescence regularities have been studied in new erbium/ytterbium materials based on glasses and glass ceramics of a magnesium-aluminosilicate
system containing nanoscale erbium/ytterbium zirconate titanate crystals with the pyrochlore structure. Lifetimes of Yb3+ and Er3+ ions in the 2 F5/2 state and in the 4I11/2 and 4I13/2 states, respectively, and the efficiency of Yb3+ → Er3+ energy transfer have been evaluated. The identified spectral-luminescent characteristics of the studied glasses and glass
ceramics co-doped with erbium and ytterbium ions show that these materials are promising media for producing laser generation
in the spectral range around 1.5 μm. 相似文献
12.
Kun Yin Hui Xu Gaoyu Zhong Gang Ni Wei Huang 《Applied Physics A: Materials Science & Processing》2009,95(2):595-600
A novel europium complex Eu(TTA)3(CPPO)2 (1) (TTA=thenoyltrifluoroacetone, CPPO=9-[4-(diphenyl-phosphinoyl)-phenyl]-9H-carbazole) based on the phosphine oxide ligand
with bipolar structure was used to fabricate double-layer devices. The strong hole injection and transport ability of 1 was proved. The luminance of 414 cd m−2 was achieved with the device configuration ITO/Eu(TTA)3(CPPO)2(40 nm)/BCP (30 nm)/Mg:Ag (BCP = 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline), which is favorable among double-layer
organic light emitting devices based on small molecular Eu3+ complexes. The maximum current efficiency of 2.44 cd A−1 and external quantum efficiency of 1.55% demonstrate the potential application of 1 as a promising candidate for high-efficiency, simple-structure and pure red-emitting devices. 相似文献
13.
Chemiluminescence (CL) of the reaction system tetracycline–H2O2–Fe(II)/(III)–Eu(III) was used for the determination of tetracycline hydrochloride in water, pharmaceutical preparations,
and honey. The CL spectrum registered for this system shows emission bands typical of Eu(III) ions, with a maximum at λ ∼ 600 nm,
corresponding to the electronic transitions of 5D0 → 7F1 and 5D0 → 7F2. A strong chemiluminescence intensity characteristic of europium(III) ions in the system tetracycline–H2O2–Fe(II)/(III)–Eu(III), as contrasted to the emission of the system tetracycline–H2O2–Fe(II)/(III) without Eu(III), proves that the Eu(III) ion plays the role of a chemiluminescence sensitizer, accompanying
tetracycline oxidation in the Fenton system (H2O2–Fe(II)/(III)). A linear dependence was observed for the integrated CL light intensity on the tetracycline concentration in
the range of 2 × 10−7 to 3 × 10−5 mol l−1 with the detection limit of 5 × 10−8 mol l−1 in aqueous solution. 相似文献
14.
Eu(III)-9-acridinecarboxylate (9-ACA) complex was synthesized and characterized by elemental analysis, conductivity measurement,
IR spectroscopy, thermal analysis, mass spectroscopy, 1H-NMR, fluorescence and ultraviolet spectra. The results indicated that the composition of this complex is [Eu(III)-(9-ACA)2(NCS)(C2H5OH)2] 2.5 H2O and the oxygen of the carbonyl group coordinated to Eu(III). The interaction between the complex with nucleotides guanosine
5′- monophosphate (5′-GMP), adenosine 5′-diphosphates (5′-ADP), inosine (5′-IMP) and CT-DNA was studied by fluorescence spectroscopy.
The fluorescence intensity of Eu(III)-9-acridinecarboxylate complex was enhanced with the addition of CT-DNA. The effect of
pH values on the fluorescence intensity of Eu(III) complex was investigated. Under experimental conditions, the linear range
was 9–50 ng mL−1 for calf thymus DNA (CT- DNA) and the corresponding detection limit was 5 ng mL−1. The results showed that Eu(III)-(9-ACA)2 complex binds to CT-DNA with stability constant of 2.41 × 104 M . 相似文献
15.
The spectral dependence of Stern–Volmer constants (KSVlK_{SV}^{\lambda} ) for fluorescence quenching by Cu2+ ions in a standard sample of humic acid (HA) (IHSS) with monochromatic excitation (λex = 337.1 nm) conditions has been studied in the spectral range 400–600 nm. This is interpreted within a concept implying that
HA macromolecules possess the property of polydispersity, which means that fluorophore-containing sites are different in terms
of chemical nature and spatial accessibility. Modeling data show that the minimum number of spectral components required for
the simulated spectral dependence of KSVlK_{SV}^{\lambda} to agree as closely as possible with that observed experimentally is three. 相似文献
16.
K. Dörschel W. Heddrich H. Hühnermann E. W. Peau W. Wagner G. D. Alkhazov E. Ye. Berlovich V. P. Denisov V. N. Panteleev A. G. Polyakov 《Zeitschrift für Physik A Hadrons and Nuclei》1983,312(3):269-270
Hyperfine structures and isotope shifts of the transition 4f7(8S 7 2/0 )6p3/2 (7/2,3/2)4?4f7(8S 7 2/0 ) 5d9D 4 0 ,λ=604.95 nm, of stable151Eu and153Eu and radioactive152Eu and154Eu have been investigated by collinear laser — ion beam Spectroscopy. Nuclear quadrupole moments have been derived. 相似文献
17.
Absolute frequency and isotope shift measurements of the cooling transition in singly ionized indium
Y. H. Wang R. Dumke J. Zhang T. Liu A. Stejskal Y. N. Zhao Z. H. Lu L. J. Wang Th. Becker H. Walther 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(2):307-311
We report greater than two orders of magnitude improvements in the absolute frequency and isotope shift measurements of the
In+ 5s2
1S0 (F = 9/2)–5s5p 3P1 (F = 11/2) transition near 230.6 nm. The laser-induced fluorescence from a single In+ in a radio-frequency trap is detected. The fourth-harmonic of a semiconductor laser is used as the light source. The absolute
frequency is measured with the help of a frequency comb referenced to a Cs atomic clock. The resulting transition frequencies
for isotopes 115In+ and 113In+ are measured to be 1 299 648 954.54(10) MHz and 1 299 649 585.36(16) MHz, respectively. The deduced cooling transition frequency
difference is 630.82(19) MHz. By taking into account of the hyperfine interaction, the isotope shift is calculated to be 695.76(1.68) MHz. 相似文献
18.
We present measurements of the net-induced gain on the 5d–4f transition at 186 nm in LiYF4 : Nd3+ optically pumped by radiation from a molecular fluorine laser. It is found that for LiYF4 : Nd3+, one of a series of potential continuously tunable VUV lasers, relatively strong excited-state absorption results in net-induced
loss. The prospects for VUV laser operation being realised in other rare-earth-doped fluorides is discussed.
Received: 4 March 1996/Revised version: 10 July 1996 相似文献
19.
The layered LiNi0.5Mn0.47Al0.03O2 was synthesized by wet chemical method and characterized by X-ray diffraction and analysis of magnetic measurements. The
powders adopted the α-NaFeO2 structure. This substitution of Al for Mn promotes the formation of Li(Ni0.472+Ni0.033+Mn0.474+Al0.033+)O2 structures and induces an increase in the average oxidation state of Ni, thereby leading to the shrinkage of the lattice
unit cell. The concentration of antisite defects in which Ni2+ occupies the (3a) Li lattice sites in the Wyckoff notation has been estimated from the ferromagnetic Ni2+(3a)–Mn4+(3b) pairing observed below 140 K. The substitution of 3% Al for Mn reduces the amount of antisite defects from 7% to 6.4–6.5%.
The analysis of the magnetic properties in the paramagnetic phase in the framework of the Curie–Weiss law agrees well with
the combination of Ni2+ (S = 1), Ni3+ (S = 1/2) and Mn4+ (S = 3/2) spin-only values. Delithiation has been made by the use of K2S2O8. According to this process, known to be softer than the electrochemical one, the nickel ions in the (3b) sites are converted into Ni4+ in the high spin configuration, while Ni2+(3a)–Mn4+(3b) ferromagnetic pairs remain, as the Li+(3b) ions linked to the Ni2+(3a) ions in the antisite defects are not removed. The results show that the antisite defect is surrounded by Mn4+ ions, implying the nonuniform distribution of the cations in agreement with previous NMR and neutron experiments. 相似文献
20.
Liu JM Gao F Gao WY Zeng LQ Huang XM Li ZM Huang XC Lin WN Wang FM Nie CL 《Journal of fluorescence》2008,18(2):573-579
When 1.00 mol l−1 I− is used as ion perturber, rhodamine 6G (Rh 6G) can emit strong and stable room temperature phosphorescence (RTP) on filter
paper substrate in KHC8H4O4–HCl buffer solution (pH = 3.50), heated at 70 °C for 10 min. NaIO4 can oxidize Rh 6G, which makes the RTP signal quench. Terbutaline sulfate (TBS) can inhibit NaIO4 from oxidizing Rh 6G, which makes the RTP signal of Rh 6G enhance sharply. The content of TBS is linear correlation to ΔIp of the system. Based on the facts above, a new inhibition solid substrate-room temperature phosphorimetry (SS-RTP) for the
determination of trace TBS has been established. The linear range of this method is 0.0104–2.08 pg spot−1 (corresponding concentration: 0.026–5.2 ng ml−1, with a sample volume of 0.4 μl) with a detection limit (L.D.) of 2.6 fg spot−1 (corresponding concentration: 6.5 × 10−12 g ml−1), and the regression equation of working curve is ΔIp = 2.040 + 54.54 mTBS (pg spot−1), n = 6, correlation coefficient is 0.9994. For the samples containing 0.0104 pg spot−1 and 2.08 pg spot−1 TBS, the relative standard deviation (RSD) are 3.8% and 2.3% (n = 8), respectively, indicating good precision. This method has been applied to determination of trace TBS in the practical
samples with satisfactory results. The reaction mechanism of NaIO4 oxidizing Rh 6G to inhibit SS-RTP for the determination of trace TBS is also discussed. 相似文献