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1.
The emission of Ni2+ ions in MgO, KMgF3, KZnF3 and MgF2 crystals has been investigated. The fine structure on the bands at about 20 000 cm-1 and 13 000 cm-1 has been studied in detail and from this and the excitation spectra these bands are assigned to and transitions respectively. 相似文献
2.
Optical absorption spectra of Ni2+ in (NH4)2Mg(SO4)2·6H2O and Co2+ in Na2Zn(SO4)2·4H2O single crystals have been studied at room and liquid nitrogen temperatures. From the nature and position of the observed bands, a successful interpretation could be made assuming octahedral symmetry for both the ions in the crystals. The splitting observed for band in Ni2+ and band in Co2+ at liquid nitrogen temperature have been explained as due to spin-orbit interaction. The extra band observed at 16,325 cm-1 in the case of Ni2+ at low temperature has been interpreted to be the superposition of vibrational mode of SO2-4 radical on band. The observed band positions in both the crystals have been fitted with four parameters B, C, Dq and ζ. 相似文献
3.
From a study of (p,t) reactions on 31P and 30Si it is suggested that in 29P the states with and , the pair , , and the pair , are related by weak coupling of a s proton with the states 01+, 02+, 21+ and 41+ respectively of 28Si. Completely atypical L = 2 angular distributions have been obtained for the and states in 29P and it is suggested that this is due to contribution by two-step processes. 相似文献
4.
The absorption and MCD spectra of the , , and spin-allowed transitions of Cr3+ in K2NaGaF6 are reported. It is shown that transitions to the . states are induced by T1u vibratio the other spin-allowed transition, , there are three competing intensity mechanisms: electric dipole induced by T1u vibrations, electric dipole induced by T2u vibrations and magnetic dipole, and an estimate is made of the relative importance of these. The magnetic dipole zero-phonon line is observed to be accompanied by a vibrational sideband for which the coupling is predominantly with T2u vibrations. Other weak transitions are observed in MCD spectra and their origin briefly discussed. 相似文献
5.
The paramagnetic susceptibility of Ti(Fe, Co) was measured in the temperature range from 10 to 300 K. The experimental results are explained in terms of the recent model of Fe antistructure atoms (responsible for magnetic ordering) dispersed in the itinerant matrix keeping the regular CsCl structure. The theoretical fits performed according to the relation resulted in a set of parameters showing good agreement with the recent understanding of the system. The low temperature behaviour (above the ordering temperatures) is explained in terms of cluster formation. 相似文献
6.
T. Minamisono J.W. Hugg D.G. Mavis T.K. Saylor H.F. Glavish S.S. Hanna 《Physics letters. [Part B]》1976,61(2):155-157
Polarized β-emitting , nuclei were produced in the reaction in thick polycrystalline targets of KBr, KCaBr3, and KCaI3 which served as hosts for the nuclei. The net polarization transferred to the nuclei was detected by measuring the asymmetry in the β-decay. The magnetic dipole moment of was measured by NMR detection. Including a diamagnetic correction we obtain ω=1.0216(2) nm. 相似文献
7.
A.M. Stewart 《Solid State Communications》1973,12(6):455-459
Critical effects in the spin disorder resistivity of the metallic antiferromagnet ErZn12 have been observed. The ordering temperature of 2.77 ± 0.01 K is low enough for there to be no phonon contribution to the resistivity present. Below this temperature, the temperature derivative of the resistivity is described best by a divergence of a logarithmic form; above it, a divergence either of the type ( or of logarithmic form is consistent within experimental error. Possible deviations from Matthiessen's Rule have been observed above the ordering temperature; they are proportional to the estimated phonon resistivity at low temperature, and vary as T3 at higher temperature. 相似文献
8.
Emission spectra for the electronic transitions , , , , , , , and of 4He2 are reported and the electronic structure of the triplet states associated with v = 0 of (1σg)2(1σu) nsσ and ndλ characterized. The energy levels comprising the and the manifolds exhibit strong channel mixing, while the mixing of the with the channel structure is relatively minor. Models based on multichannel quantum defect theory are used to aid in the spectral assignments and to correlate the observed level structures. We show that three-limit and two-limit models adequately represent the bulk of the observed and channel structures, respectively. 相似文献
9.
M. Drillon J. Darriet P. Hagenmuller R. Georges 《Journal of Physics and Chemistry of Solids》1980,41(5):507-515
A trinuclear cluster (Ru3O12)13? occurs in the Ba4NbRu3O12, and Ba4TaRu3O12 compounds where the oxydation states of ruthénium are +III and +IV. The exchange interaction between magnetic sites is described by a Hamiltonian, which takes account of the orbital degeneracy of the terms. For these ions, the spin-orbit coupling is the dominant effect and it appears that the low temperature magnetic susceptibility depends essentially on the orbital reduction factor and the distortion of the coordination octahedra. There is apparently no first order perturbation of the ground state due to the interaction between magnetic ions. 相似文献
10.
Excitation functions at θ = 90° have been measured for , , and , in the range E3He = 3–19 MeV. The first reaction has also been studied at θ = 40°. Excitation functions at 90° have also been measured for and for E3He = 19–26 MeV. Angular distributions have been measured for the first four reactions.For the most excitation functions, a broad peak is observed, several MeV wide, centred at about Ex≈ 20 MeV. Superimposed on this, in some cases, are narrower peaks, with width ≈ 1 MeV. Energies and widths have been extracted for all resonances.Cluster-model calculations have been carried out, using methods similar to those which have proved successful for low-lying states in A= 18–19 nuclei. No satisfactory correspondence with the present results was found. The shell model has been used to calculate Γ3He and Γγ for 1?ω excitations in the final nuclei. These generally show good agreement with the trends of the experimental data. The results are consistent with the excitation of the giant dipole resonance in 3He capture, but much more weakly than in proton capture. 相似文献
11.
A.R.W McKellar 《Journal of Molecular Spectroscopy》1981,86(1):43-54
Magnetic dipole transitions between the and components of the ground electronic state of BrO have been detected using the technique of laser magnetic resonance on three CO2 laser lines between 964 and 970 cm?1. This is the first direct observation of the state in BrO. The spin-orbit splitting parameter, A, is determined to be ?967.9831(2) cm?1 for 79Br16O and ?967.9981(2) cm?1 for 81Br16O. Accurate values for the rotational constant , the hyperfine parameters () and d, the Λ-doubling parameter p, and the Zeeman parameter g| are also determined from an analysis of the measured spectra. 相似文献
12.
P. Heitjans H. Grupp W. Buttler F. Fujara H. Ackermann K. Dörr G. Kiese A. Körblein H.-J. Stöckmann 《Physics letters. [Part B]》1980,94(1):28-31
Polarized isomeric nuclei were produced by capture of polarized thermal neutrons in a NaF single crystal at room temperature. The asymmetric β-decay radition of 24Nam was used to detect nuclear magnetic resonance signals yielding the magnetic moment (uncorrected). 相似文献
13.
A synthetic germanium-doped crystal of α-quartz was subjected to an electro-diffusion process , 625°K), in which Ag+ ions were introduced along the crystal's optic axis (c). A 9800MHz electron paramagnetic resonance spectrum at room temperature, taken after room temperature x-irradiation, revealed the presence of a silver-compensated germanium center AGe?Ag with large, almost isotropic 107Ag and 109Ag hyperfine splittings (26.078, 30.112 mT for magnetic field B∥c). Measurement of the spin-Hamiltonian (i.e. matrices , , and discloses that a suitable model for the observed center utilizes germanium, substituted for silicon, with the accompanying silver interstitial in a nearby c-axis channel, and with electronic structure in which an appreciable admixture Ge4+?Ag0 to Ge3+?Ag+ exists. Estimates of the unpaired electron orbital are presented. 相似文献
14.
The electronic properties of single crystals of monoclinic SrAs3 have been studied by investigating the temperature dependence of electrical conductivity, Hall effect and Shubnikov de Haas (SdH) oscillations. At 4.2 K, SrAs3 is predominantly p-conducting with a typical hole concentration of 6 × 1017cm-3. The Hall coefficient changes its sign near 80 K. The angular dependence of the SdH oscillations was used to map out the shape of the Fermi-surface of holes. Two asymmetric, quasi-ellipsoidal Fermi-bodies are located in the first Brillouin zone. The cyclotron effective masses for two crystallographic directions were calculated from the temperature dependence of the amplitude of the oscillations: and , respectively. There are indications for a third Fermi-surface which is attributed to electrons. 相似文献
15.
The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a transition from Fe2+ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes and , respectively, which take into account Fe 3dn?1 final state effects. 相似文献
16.
We report, for the first time, cw room temperature laser action of Cr3+:Gd3Sc2Al3O12. These crystals show a strong band fluorescence due to the transition with a lifetime of 150 μs. Laser pumping in the blue and red spectral range yields a minimum threshold of 170 mW and slope efficiencies up to 18.5%. The emission of the free running laser is centered at 784 nm with a FWHW of 5 nm. The extension of the Ga-garnets to Al-garnets as suitable host lattices for Cr3+ reveals the variety of garnet-structured crystals having an appropriate ligand field for continuously tunable laser operation. 相似文献
17.
A. Kawabata 《Solid State Communications》1980,34(6):431-432
Theory of negative magnetoresistance in two-dimensional systems due to delocalization of electrons by magnetic field by Hikami, Larkin, and Nagoaka is extended to the case of three-dimension. The increase in conductivity by magnetic field is independent of the direction of the current relative to that of the magnetic field, and is proportional to , τ? being energy relaxation time of electrons, when the magnetic field H is small. If τ? is large enough at low temperature and H is not too small, it is independent of the parameter characterizing the system, and is of the form (H in kOe). 相似文献
18.
Marek Danielewski Jaeosław Da̧bek Stanisł;aw Mrowec Grażyna Siemińska 《Solid State Ionics》1985,17(4):331-335
Using the re-equilibration kinetic method the chemical diffusion coefficient in nonstoichiometric chromium sesquisulfide, Cr2+yS3, has been determined as a function of temperature (1073–1373 K) and sulphur vapour pressure (10?104 Pa). It has been found that this coefficient is independent of sulphur pressure and can be described by the following empirical equation: . It has been shown that the mobility of the point defects inCr2+yS3 is independent of their concentration and that the self-diffusion coefficient of chromium in this sulfide has the following function of temperature and sulphur pressure: . (cm2s?1). 相似文献
19.
The microwave spectrum of MnO3F has been remeasured and several corrections and new results have been obtained: B0 = 4129.141 MHz, DJ = 1.12 kHz, DJK = 1.87 kHz; , , , |q5| = 16.005, and |q6| = 8.456 MHz. 相似文献
20.
A high density perturbation expansion method is employed to calculate the contribution of two-magnon difference processes to the light scattering spectrum of antiferromagnets. The theory is applicable for temperatures below about (TN = Néel temperature), where magnon damping effects are relatively small. Results are presented for the cubic perovskite KNiF3. 相似文献