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1.
Abstract

Solid Cu(2-Benzoylpyridine)2(NO3)2 has been studied by UV-Vis, IR, and EPR (X-band, Q-band) techniques. Monoclinic crystal symmetry was determined with two molecules per unit cell. Copper (II) is coordinated by two benzoylpyridine ligands and a single NO3 group in the chromophore CuN2O3 of distorted trigonal bypiramidal stereochemistry. Exchange coupling values were determined from EPR spectra as |J| = 0.0026(2) cm?1 between magnetically nonequivalent copper (II) sites, and |J| < O.3 cm?1 between equivalent sites.

Results are discussed by a comparison with Cu(II)-benzoyl-pyridine complexes coordinated with azide N3 ? anions.  相似文献   

2.
The influence of activators, especially copper, on the electric properties of vacuum-evaporated electroluminescent layers excited by dc voltage is investigated. In the course of the “one step” method of preparation, non-uniform incorporation of the activators occurs. The layers are divided into three groups according to the copper concentration. 1 — “low” (1×10?3 g Cu/g ZnS) with the emission stimulated at Al? electrode, 2 — “medium” (5–8×10?3 g Cu/g ZnS) with the emission at both polarities, 3 — “high” (9×10?3?5×10?2 g Cu/g ZnS) with the emission at Al+ electrode. Layers in these groups differ not only in their electrical properties and in the existence of the forming process but they have also various distribution of the light-emitting regions. The light emission has been found in the intermediate regions between the microcrystalline grains as well as on the interface between the microcrystalline grain and ZnS phosphor phase. According to structural properties the light emission originates from microcrystalline grains too.  相似文献   

3.
The effect of low-flux (I ~ 1.8 × 105 cm?2 s?1) β irradiation on the process of the delamination of thin copper films (with a thickness of ~100 nm) from a silicon substrate under indentation by a Berkovich pyramid is studied. It is revealed that irradiation with a fluence of F = 3.24 × 1010 cm?2 leads to an increase in the perimeter and area of the copper-film delaminations formed upon penetration of the indenter. This indicates a β-induced reduction in adhesion in the Cu/Si structure.  相似文献   

4.
ESR investigations on exchange coupled pairs of Cu ions in single crystals of Cu(dtc)2, isomorphously diluted with the corresponding diamagnetic zinc salt, are reported. The spin Hamiltonian parameters for the coupled species (S=1) are:g =2.1025,g +=2.031,A=75.1×10−4 cm−1,B=14.8×10−4,D=276.0×10−4 cm−1 andE=46.7×10−4 cm−1. While theg andA tensors show tetragonal symmetry, the zeor-field splitting tensor is rhombic and has principal axes different from those of theg andA tensors. Intensity measurements made down to 4.2 K indicate that the exchange is ferromagnetic with |FFF| ∼ 10 cm−1. Direct dipole-dipole interaction appears to be the major contribution to the zero-field splitting. A calculation on the distributed point dipole model shows that dipolar interaction is considerably modified by the high covalency of the Cu-S bond and accounts for the rhombic nature of the tensor. The possible exchange mechanisms in Cu(dtc)2—direct exchange and superexchange through the bridging sulphurs—are discussed.  相似文献   

5.
The phonon-defect interaction in KC1:CN? has been studied in the 16 GHz frequency range using the Brillouin scattering technique. Brillouin spectra of KC1:CN? at 4.2 K show a defect induced phonon velocity renormalization. The measurements are consistent with a 〈111〉 oriented CN? dipole in KC1 with a tunneling level of T2g symmetry at 2.6 cm?1 and a coupling constant of 1.5 × 10?21 cm3.  相似文献   

6.
Laser pulses generate electron-hole pairs in a ZnSe crystal and selective trapping alters the carrier concentration. A result is modulated optical absorption Δα, probed by a second monochromatic beam. The effect is extrinsic and may be associated with ionized Cu in substitution for Zn. Phase-sensitive kinetics measurements reveal a thermal component and indicate that at least two impurity levels are involved, the latter with photon-capture cross sections q in the range 0.3 × 10?16 to 0.9 × 10?16cm2, corresponding to non-equilibrium carrier concentrations Δn?1013cm?3.  相似文献   

7.
Dipole moment functions, both perpendicular and parallel to the molecular axis, are calculated from the SCF and MRD-CI results of a previous study for the normal ν2 bending vibrations of HCN and DCN. Vibrationally averaged dipole moments and the infrared transition matrix elements are then obtained from the dipole moment functions and vibrational wave functions. MRD-CI results, with known experimental values in parentheses, for HCN are 〈0|μ|0〉 = ?2.954(?2.985) D, 〈1|μ|1〉 = ?2.915(±2.942) D, 〈0|μ|1〉 = 0.148(0.147) D, 〈0|μ|2〉 = ?0.027 D, 〈1|μ|2〉 = 0.210 D. Calculated absolute intensities at 1 atm and 0°C for the (0200) ← (000), (0200) ← (010), and (0220) ← (010) bands of HCN are 25 (40 ± 10 as estimated from spectra), 8.5, and 17.0 atm?1 cm?2, respectively. Results for DCN are also reported.  相似文献   

8.
Reflection absorption infrared spectroscopy has been used in conjunction with LEED and surface potential measurements to study low temperature CO adsorption on the oxidised Cu surfaces Cu(111)O|32?2|, Cu(110)O(2 × 1) and Cu(110)Oc(6 × 2). On all three surfaces adsorption at 80 K yields surface potential changes in excess of 0.6 V and does not lead to the formation of an ordered overlayer. At high coverages the adsorption enthalpy is lower than on the clean surfaces. Infrared spectra show the growth of a doublet band with components initially at 2100 and 2117 cm?1 on the oxidised Cu(111) surface. Similar features seen on the oxidised Cu(110) surfaces are accompanied by a band at 2140 cm?1: a very weak band at the same frequency on oxidised Cu(111) is attributed to defect sites. Studies of the temperature dependence of the spectrum from oxidised Cu(111) lead to the conclusion that two different binding sites are occupied. Spectra of 12CO13CO mixtures show that the molecules occupying these sites are in close proximity to each other, and that the spectrum is subject to large but opposing coverage-dependent frequency shifts.  相似文献   

9.
The potential energy curve and theoretical dipole moment function of the a4Π state of NO have been determined using full-valence and first-order configuration interaction wavefunctions. Using these two different wavefunctions, the dipole moments of the a4Π, v = 3 level have been found equal, respectively, to 0.16 D and 0.30 D, with the polarity N+O?. These values compare well with the value of |0.20 ± 0.04| D determined by Lisy and Klemperer. The first derivative of the dipole moment has also been calculated to be equal to 1.25–1.73 D/bohr.  相似文献   

10.
Photoluminescent studies give evidence for the existence of the electron—hole droplet in phosphorus-doped silicon in the impurity concentration range 9.0 × 1015cm?3 ? ND ? 4.3 × 1019cm?3.  相似文献   

11.
The dimerization of 5-(4’-(aza-15-crown-5)-phenyl) copper porphyrin (CuP) upon the addition of the K(SCN) salt to a solution of the CuP monomer has been proven by electron paramagnetic resonance (EPR). The magnetic resonance parameters of the CuP monomer, the exchange interaction parameter, J = +0.25 cm?1, and the Cu–Cu distance of the CuP dimer have been determined by comparing the experimental continuous-wave EPR spectra with the results of the numerical calculations. The photoexcited states have been studied in the time-resolved EPR experiments. It has been shown that the time-resolved EPR spectra of the dimerized porphyrins can be presented as a sum of two components that represent the spectra derived by integrating the dataset in the time windows of 1.1–1.3 and 2.1–2.3 μs. To describe the spectrum in the time window of 2.1–2.3 μs, it is assumed that there is an essential contribution to the signal from the excited state of the supramolecule, which is formed by the interaction between the photoexcited porphyrin in the quartet state and the neighboring non-excited porphyrin in the ground state.  相似文献   

12.
Single-crystal X and Q band EPR of a hydrogen-bridged l-dimensional Cu(II) complex, [Cu(stpy)2(CH3COO)2(H2O)2] [CU(stpy)2(CH3COO) 2(H2O)], containing both octahedral and square pyramidal geometries in the same unit cell, has been studied at 300 K. EPR of powder samples at X band frequencies at 300 K and 77 K show exchange-narrowed resonance. The peak-to-peak linewidths of the signals are 80 G and 85 G, respectively. However, at Q band frequencies it exhibits an axially symmetric spectrum with spin Hamiltonian parameters g|| = 2.303 and g = 2.077, corresponding to an |x2 ? y2〉 ground state. Single-crystal X band EPR spectra show a single resonance line for all the orientations, indicating the complex to be in the strong exchange regime. On the other hand, Q band spectra exhibit two lines corresponding to the weak exchange regime. An estimate of the interchain-site exchange coupling constant J′ = 0.0125(3) cm?1 also reveals weak coupling between the magnetically distinct Cu(II) centres. The ratio of J′/J = 8.25 × 10?2 is low enough to make the interactions almost l-dimensional, in agreement with X-ray data. EPR linewidth and lineshape analyses also support l-dimensional behaviour of the system.  相似文献   

13.
α-Al2O3单晶中Fe3+离子的电子顺磁共振   总被引:1,自引:0,他引:1       下载免费PDF全文
本文对α-Al2O3单晶体中Fe3+离子在室温下,X波段进行了电子顺磁共振研究,发现Fe3+离子实际上占据四种磁性不等价晶位。在同一氧离子层间的两种晶位上的Fe3+离子具有相同的自旋哈密顿参量,而不同氧离子层间的晶位上的Fe3+离子具有不同的自旋哈密顿参量,两种自旋哈密顿参量为:(1)g=2.001,g=2.003,D=1679 关键词:  相似文献   

14.
A study is made into the temperature dependence of residual polarization of negative muons in crystalline silicon with the concentration of impurity of the n-and p-types ranging from 8.7×1013 to 4.1× 1018 cm?3. The measurements are performed in a magnetic field of 1000 G transverse to the muon spin, in the temperature range from 4.2 to 300 K. The form of the temperature dependence of the relaxation rate v of the magnetic moment of the μAl0 acceptor in silicon is determined. For a nondegenerate semiconductor, the relaxation rate depends on temperature as vT q (q ≈ 3). A variation in the behavior of the temperature dependence and a multiple increase in the relaxation rate are observed in the range of impurity concentration in excess of 1018 cm?3. The importance of phonon scattering and spin-exchange scattering of free charge carriers by an acceptor from the standpoint of relaxation of the acceptor magnetic moment is discussed. The constant of hyperfine interaction in an acceptor center formed by an atom of aluminum in silicon is estimated for the first time: |A hf (Al)/2π| ~ 2.5×106s?1.  相似文献   

15.
Electron spin resonance experiments on Cu2+ doped in a single crystal of cadmium oxalate trihydrate grown by a slow diffusion technique have been carried out at 77 K. The major features of the ESR spectra can be attributed to divalent copper (3d9) in substitutional Cd2+ sites. Information has been gained about the hyperfine and quadrupole interactions concerning the ion. The spin-Hamiltonian parameters in the S = 12, I = 32 manifold are: gx = 2.0211; gy = 2.2249; gz = 2.4536; Ax = +84.5 × 10?4cm?1; Ay = +16.8 × 10?4cm?1; Az = ?40.8 × 10 × ?4cm?1; Px = ?7.4 × 10?4cm?1; Py = ?0.4 × 10?4cm?1; and Pz = +7.8 × 10?4cm?1. An evaluation of the asymmetry and quadrupole coupling parameters revealed that the ground state of the guest ion in Cd(COO)2 · 3H2O is 0.97|x2 ?y2 > +0.24 |3z2 ? r2 >.  相似文献   

16.
The moment of inertia of the proto neutron star PSR J0348+0432 is studied in the framework of relativistic mean field theory under neutrino trapped. We find that the temperature of the PNS PSR J0348+0432 increases with the increase of the baryon number density and at the center of the star it is in the range Tc = 41.662–45.685 MeV. Corresponding to the observation mass 1.97–2.05 M, the radius of the NS PSR J0348+0432 is in the range 12.948–12.16 km whereas that of the PNS PSR J0348+0432 is in the range 14.46–13.561 km. The radius of the PNS PSR J0348+0432 has increased by 11.7%–11.5% compared with that of the NS PSR J0348+0432. The central moment of inertia of the PNS PSR J0348+0432 is in the range 2.207?×?1045–1.914?×?1045 g cm2 whereas that of the NS PSR J0348+0432 is only in the range 1.9?×?1045–1.552?×?1045 g cm2. Compared with the moment of inertia of the NS PSR J0348+0432, the central moment of inertia of the PNS PSR J0348+0432 increases by 16%–23%.  相似文献   

17.
We report a new measurement of the neutron electric dipole moment with the PNPI EDM spectrometer using the ultracold neutron source PF2 at the research reactor of the ILL. Its first results can be interpreted as a limit on the neutron electric dipole moment of |d n | < 5.5 × 10?26 e cm (90% confidence level).  相似文献   

18.
Speciation of copper in a copper‐rich chemical‐mechanical polishing sludge during electrokinetic treatment has been studied by in situ extended X‐ray absorption fine structure (EXAFS) and X‐ray absorption near‐edge structure (XANES) spectroscopy. The least‐squares‐fitted XANES spectra indicate that the main copper species in the sludge are Cu(OH)2 (74%), nanosize CuO (20–60 nm) (13%) and CuO (>100 nm) (13%). The average bond distance and coordination number (CN) of Cu—O are 1.96 Å and 3.5, respectively. Under electrokinetic treatment (5 V cm?1) for 120 min, about 85% of the copper is dissolved in the electrolyte, 13% of which is migrated and enriched on the cathode. Notably the copper nanoparticles in the sludge can also migrate to the cathode under the electric field. By in situ EXAFS, it is found that during the electrokinetic treatment the bond distance and CN of Cu—O are increased by 0.1 Å and 0.9, respectively.  相似文献   

19.
Vanadium dioxide thin films have been deposited on Corning glass substrates by a KrF laser ablation of V2O5 target at the laser fluence of 2 J?cm?2. The substrate temperature and the target-substrate distance were set to 500 °C and 4 cm, respectively. X-ray diffraction analysis showed that pure VO2 is only obtained at an oxygen pressure range of 4×10?3–2×10?2 mbar. A higher optical switching contrast was obtained for the VO2 films deposited at 4×10?3–10?2 mbar. The films properties were correlated to the plume-oxygen gas interaction monitored by fast imaging of the plume.  相似文献   

20.
X-band electron paramagnetic resonance (EPR) studies are carried out on Fe3+ ions doped in ammonium dihydrogen phosphate (ADP) single crystals at room temperature. The crystal field and spin Hamiltonian parameters are evaluated from the resonance lines obtained at different angular rotations. The obtained values of spin Hamiltonian and zero-field parameters of the Fe3+ ion in ADP are: g = 1.994 ± 0.002, |D| = (220 ± 5) × 10?4 cm?1 and a = (640 ± 5) × 10?4 cm?1. On the basis of EPR data, the site symmetry of the Fe3+ ion in the crystal is discussed. The Fe3+ ion enters the lattice substitutionally replacing the NH4 + sites. The optical absorption of the crystal is also studied at room temperature in the wavelength range of 195–925 nm. The energy values of different orbital levels are calculated. The observed bands are assigned as transitions from the 6 A 1g (S) ground state to various excited quartet levels of the Fe3+ ion in a cubic crystalline field. From the observed band positions, Racah interelectronic repulsion parameters (B and C), cubic crystal field splitting parameter (D q ) and Trees correction are calculated. There values are: B = 970, C = 1,923, D q  = 1,380 cm?1 and α = 90 cm?1, respectively. On the basis of EPR and optical data, the nature of bonding in the crystal is discussed. The zero-field splitting (ZFS) parameters are also determined theoretically using B kq parameters estimated from the superposition model. The values of ZFS parameters thus obtained are |D| = (213 ± 5) × 10?4 cm?1 and |E| = (21 ± 5) × 10?4 cm?1.  相似文献   

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