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A. V. Loginov 《Optics and Spectroscopy》2003,95(6):869-872
A semiempirical least squares method is used to determine the wave functions for the intermediate coupling between the 4d 95s, 4d 95p, and 4d 95d levels in the XeIX-CeXIII spectra and to calculate the radiative lifetimes of the 4d 95p and 4d 95d levels in these spectra. 相似文献
3.
V. S. Pokatilov 《Journal of Experimental and Theoretical Physics》2003,96(1):59-65
Effects of hybridization of 3d bands of iron with 3d bands of scandium and 4d bands of yttrium in Sc1?xYxFe2 cubic Laves alloys (0≤x≤1) are studied by the nuclear magnetic resonance method. The concentration dependences of the lattice parameters a, saturation magnetization σ, and hyperfine fields at the 57Fe, 45Sc, and 89Y nuclei—as well as the 27Al impurity nuclei, whose atoms substitute iron atoms in the lattices of these alloys—are measured. The “local” and “induced” contributions to hyperfine fields at the 57Fe nuclei are separated and the magnetic moments at iron atoms are estimated. It is found that the hybridization effect leads to the formation of magnetic moments at Sc and Y atoms (whose direction is opposite to the direction of the magnetic moment at iron atoms) and is responsible for the ferrimagnetic structure in Sc1?xYxFe2 alloys. 相似文献
4.
A. V. Loginov 《Optics and Spectroscopy》2002,93(5):649-652
The radiative lifetimes of the 5p 5 (6s+5d), 5p 5 (6p+4f), and 5p 55f levels in the spectrum of the Ba III ion are calculated. The wave functions of the intermediate coupling are found from the experimental energy levels by the method of least squares. The radial transition integrals are calculated by the Hartree-Fock method. 相似文献
5.
E. P. Ivanova 《Optics and Spectroscopy》2009,107(1):1-8
The wave functions of one-electron states above the 4d 10 core have been calculated within the relativistic perturbation theory with a zero-order model potential. The wavelengths and probabilities of electric dipole transitions in an Ag-like ion have been calculated for the 5s-5p, 5p-5d, 5d-5f, and 4f-5d transitions. The data obtained are compared with the results of calculations by the relativistic Hartree-Fock method and within the relativistic many-body perturbation theory. The theoretical results are compared with experimental data on the lifetimes of energy levels in Ag-like ions. 相似文献
6.
A. V. Loginov 《Optics and Spectroscopy》2017,122(3):345-351
The probabilities of radiative electric dipole transitions 2p 53p, 2p 6–2p 53s, and 2p 53d in the spectrum of neon-like copper Cu XX and 5p 56p, 5p 6–5p 56s, 5p 57s, and 5p 55d in the spectrum of xenon-like lanthanum La IV are calculated. The wave functions of the intermediate coupling were found from the wellknown experimental energy levels by the least-squares method (LSM). To transfer to an absolute scale the radial integrals for the transitions calculated in the form of a length on the Hartree–Fock functions have been used. By summing the calculated probabilities of the transitions, the lifetimes of the levels of configurations 2p 53s, 2p 53p, and 2p 53d in the spectrum of Cu XX and levels of configurations 5p 56s, 5p 56p, and 5p 57s in the spectrum of La IV have been obtained. 相似文献
7.
I. E. Matyash I. A. Minailova O. N. Mishchuk B. K. Serdega 《Optics and Spectroscopy》2017,123(6):881-888
The increments of the real and imaginary components of the complex refractive index ΔN = Δn–iΔk of a lightly doped GaAs crystal with a donor concentration of ~1016 cm–3 have been measured using modulation polarimetry. It is shown that, within this representation, the birefringence and dichroism spectra (Δn(ω) and Δk(ω), respectively) obtained in the transparency window of a sample subjected to probe strain are derivatives of the corresponding functions: Δn(ω) ≈ dn/dω and Δk(ω) ≈ dk/dω. The experimental characteristics and primary dependences n(ω) and k(ω) derived from them by graphical integration are in agreement with the results of other researchers and measurements carried out by independent methods. The results obtained are compared (taking into account the integral (Kramers–Kronig) relations) with the resonance parameters: amplitude and phase in the Drude–Lorenz model. Agreement between the experimental characteristics and theoretical model predictions can be obtained by choosing an appropriate value of resonance damping parameter. 相似文献
8.
The evolution of the electronic structure of CeNi4M (M = Fe, Co, Ni, Cu) intermetallics depending on the type of nickel substitutional impurity is explored. We have calculated band structures of these compounds and considered options of substituting one atom in nickel 3d sublattice in both types of crystallographic positions: 2c and 3g. The analysis of total energy self-consistent calculations has shown that positions of 2c type are more energetically advantageous for single iron and cobalt impurities, whereas a position of 3g type is better for a copper impurity. The Cu substitutional impurity does not change either the nonmagnetic state of ions or the total density at the Fermi level states. Fe and Co impurities, on the contrary, due to their considerable magnetic moments, induce magnetization of 3d states of nickel and cause significant changes in the electronic state density at the Fermi level. 相似文献
9.
N. Yu. Svechnikov V. G. Stankevich A. M. Lebedev L. P. Sukhanov K. A. Menshikov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2016,10(1):23-34
The electron and spin structure of thick smooth hydrocarbon CD x films (“flakes”) with a high relative deuterium concentration of x ~ 0.5, redeposited from deuterium plasma discharge onto the walls of the vacuum chamber of the T-10 tokamak and containing ~1 at % of 3d-metal impurities due to erosion of the chamber walls, are studied using electron paramagnetic resonance (EPR) and photoluminescence (PL). The resulting spectra are compared for the first time to the EPR and photoluminescence spectra of polymer (soft) a-C:H(D) films (H(D)/C ~ 0.5), which are considered model analogues of smooth CD x films. A certain similarity of the CD x films with a-C:H films was found in the electronic structure of the valence band. At the same time, the differences in the EPR and photoluminescence spectra were observed due to the presence of 3d-metal impurities in the CD x samples, contributing to the conversion of sp 3 → sp 2 in the formation of films in the tokamak and upon heating and thermal desorption. An impurity of, presumably, 3d metals was detected for the first time by EPR in the a-C:H films in an amount of approximately 0.2 ppm, related to the evaporation of graphite. 相似文献
10.
E. P. Ivanova 《Optics and Spectroscopy》2007,103(5):733-740
The method of extrapolation of the parameter of a model potential for states of one electron (4f, 5s, 5p, 5d, 5f) above the core 1s 22s 22p 63s 23p 63d 104s 24p 64d 10 and one vacancy (4d 9) in the same core is applied to calculate the energy levels in the silver and rhodium isoelectronic sequences with the maximum nuclear charge Z = 86. The energy levels of Ag-and Rh-like ions were used for the calculation of the energies of resonance transitions to the ground state 1 S 0 in Pd-like ions. Good agreement between the theoretical and calculated energies of the resonance transitions in Pd-like ions indicates the reliability of the results obtained. 相似文献
11.
The near-threshold portions of the energy dependences of the effective excitation cross sections of the resonance transition 4d105p2P1/2° → 4d105s2S1/2 and the two-electron forbidden transition 4d95s22D5/2 → 4d105p2P3/2° in the spectrum of the Cd+ ion were investigated by the spectroscopic method in crossed electron and ion beams. In the region of energy splitting of the 2P° and 2D levels, a significant resonance contribution of the autoionizing states of cadmium (decaying during the Coster-Kronig process) to the effective excitation cross sections of the noted transitions was revealed for the first time. It is found that the resonance contribution manifests itself much more strongly for the forbidden transition in comparison with the more intense resonance transition; i.e., the manifestation of the Coster-Kronig effect in the electron excitation of ions depends strongly on the cross section of the direct process. It is ascertained that, during the Coster-Kronig process, the main contribution to the resonance excitation of both the resonance and the two-electron forbidden spectral transitions is from the low-lying terms of the series of autoionizing states 4d105p(2P3/2°)ns, md and 4d9(2D3/2)5s2ns, md, which are in the splitting region of the 2P1/2, 3/2° and 2D5/2, 3/2 levels, rather than from the high-lying atomic autoionizing states of cadmium, which are located near the ionization limits (corresponding to the and 2P3/2° and 2D3/2 levels). 相似文献
12.
The transmittance D(ω), reflectance R(ω), and dispersion ω(k) are investigated for waves of various nature propagating through a one-dimensional superlattice (multilayer structure) with arbitrary thickness of the interlayer boundary. The dependences of the band gap widths δωm and their positions in the wave spectrum of the superlattice on the interlayer boundary thickness d and the band number m are calculated. Calculations are performed in terms of the modified coupled-mode theory (MCMT) using the frequency dependence of R(ω), as well as in the framework of perturbation theory using the function ω (k), which made it possible to estimate the accuracy of the MCMT method; the MCMT method is found to have a high accuracy in calculating the band gap widths and a much lower accuracy in determining the gap positions. It is shown that the m dependence of δω m for electromagnetic (or elastic) waves is different from that for spin waves. Furthermore, the widths of the band gaps with m=1 and 2 are practically independent of d, whereas the widths of all gaps for m>2 depend strongly on d. Experimental measurements of these dependences allow one to determine the superlattice interface thicknesses by using spectral methods. 相似文献
13.
A. V. Loginov 《Optics and Spectroscopy》2018,124(2):151-154
Radiative lifetimes for the 4d94f, 4d95p, 4d95d, and 4d96s levels in the spectra of palladium-like ions Pr XIV and Nd XV are calculated in the electric-dipole approximation by the intermediate coupling semiempirical method with the use of experimental energy levels available in the literature. The radial integrals of transitions necessary for calculating absolute values of transition probabilities are obtained in the length form with Hartree–Fock functions. 相似文献
14.
Measurements of the cross sectiond 2 σ/dΩ dE′ for the inelastic electron-deuteron scattering processe+d→e+n+p have been used to determine the electromagnetic structure of the neutron. The effects on the theoretical cross section of the structure of the deuteron and of interactions between the outgoing nucleons are examined in detail. We start with the relativistic invariant expressions of the one-nucleon exchange diagram including deuteron structure to obtain the interaction Hamiltonian. For the disintegration near the quasi-elastic peak thed-n-p vertex function can be represented by nonrelativistic deuteron wave functions. The final state interaction is calculated from phenomenological nucleon-nucleon potentials. The rescattering corrections are found to lead to a decrease in the peak value of the cross section between ?6% and ?2% depending on the electron momentum transfer q2 which has been varied between 2.5f ?2 and 40f ?2. These corrections are largest for smallq 2<5f ?2. Furthermore the results show that the influence of our insufficient knowledge of the deuteron structure on the cross section is small. 相似文献
15.
R. Bock 《Zeitschrift für Physik A Hadrons and Nuclei》1961,164(5):546-557
An experiment has been accomplished which gives information on the reaction mechanism of the (Zr94,96+d)-reactions. Total cross sections and excitation functions up to 11,8 MeV have been measured for the reactions Zr94 (d, p), Zr94 (d, n), Zr96(d, p), Zr96(d, n) and Zr96(d, 2n) by the activation method. The results are compared with cross sections calculated according to the statistical theory of nuclear reactions. It is shown that the (d, p) -reactions proceed almost completely by the stripping-mechanism. The (d, n)- and (d, 2n)-excitation functions on the other hand are in good agreement with the predictions of the statistical theory and one can conclude that the compound nucleus mechanism is the dominating process. 相似文献
16.
Re-examination of Dronino iron meteorite and products of its weathering in the internal and external surface layers was carried out using Mössbauer spectroscopy with a high velocity resolution. New results showed the presence of α-Fe(Ni, Co), α 2-Fe(Ni, Co) and γ-Fe(Ni, Co) phases with variations in Ni concentration in Dronino metallic iron alloy. The surface weathering products were supposed as magnetite and/or maghemite, goethite with different particles size and probably ferrihydrite in the internal layer and goethite with different particles size and probably ferrihydrite in the external layer. 相似文献
17.
R. S. Iskhakov Zh. M. Moroz L. A. Chekanova E. E. Shalygina N. A. Shepeta 《Physics of the Solid State》2003,45(5):890-894
It has been found that the magnitude and sign of exchange interaction between Co(5 nm) and CoNi(5 nm) ferromagnetic layers through Pd depend on magnetization orientation of ferromagnetic layers. If magnetization is oriented in a layer plane, exchange interaction can be both ferromagnetic and antiferromagnetic. If magnetization orientation is orthogonal to a layer plane, the exchange constant is always positive at dPd<d c and equals zero at dPd>d c (d c is the characteristic length). 相似文献
18.
We consider Hermitian and symmetric random band matrices H in d ≥ 1 dimensions. The matrix elements H xy , indexed by \({x,y \in \Lambda \subset \mathbb{Z}^d}\), are independent, uniformly distributed random variables if \({\lvert{x-y}\rvert}\) is less than the band width W, and zero otherwise. We prove that the time evolution of a quantum particle subject to the Hamiltonian H is diffusive on time scales \({t\ll W^{d/3}}\). We also show that the localization length of the eigenvectors of H is larger than a factor W d/6 times the band width. All results are uniform in the size \({\lvert{\Lambda}\rvert}\) of the matrix. 相似文献
19.
We uncover the low-energy spectrum of a t-J model for electrons on a square lattice of spin-1 iron atoms with 3d xz and 3d yz orbital character by applying Schwinger-boson-slave-fermion mean-field theory and by exact diagonalization of one hole roaming over a 4 × 4 × 2 lattice. Hopping matrix elements are set to produce hole bands centered at zero two-dimensional (2D) momentum in the free-electron limit. Holes can propagate coherently in the t-J model below a threshold Hund coupling when long-range antiferromagnetic order across the d + = 3d (x + iy)z and d ? = 3d (x ? iy)z orbitals is established by magnetic frustration that is off-diagonal in the orbital indices. This leads to two hole-pocket Fermi surfaces centered at zero 2D momentum. Proximity to a commensurate spin-density wave (cSDW) that exists above the threshold Hund coupling results in emergent Fermi surface pockets about cSDW momenta at a quantum critical point (QCP). This motivates the introduction of a new Gutzwiller wavefunction for a cSDW metal state. Study of the spin-fluctuation spectrum at cSDW momenta indicates that the dispersion of the nested band of one-particle states that emerges is electron-type. Increasing Hund coupling past the QCP can push the hole-pocket Fermi surfaces centered at zero 2D momentum below the Fermi energy level, in agreement with recent determinations of the electronic structure of mono-layer iron-selenide superconductors. 相似文献
20.
M. V. Goryunov M. I. Oshtrakh A. V. Chukin V. I. Grokhovsky V. A. Semionkin 《Hyperfine Interactions》2016,237(1):15
A comparative study of Sikhote-Alin IIAB, Anyujskij IIAB, Aliskerovo IIIE-an and Sterlitamak IIIAB iron meteorites was carried out using Mössbauer spectroscopy with a high velocity resolution as well as using metallography, scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction. Different numbers of spectral components were found in the Mössbauer spectra of Sikhote-Alin IIAB and Anyujskij IIAB and in the spectra of Aliskerovo IIIE-an and Sterlitamak IIIAB iron meteorites. The values of hyperfine field at the 57Fe nuclei obtained for spectral components were related to α-Fe(Ni, Co), α 2-Fe(Ni, Co) and γ-Fe(Ni, Co) phases with variations in Ni concentration. 相似文献