共查询到18条相似文献,搜索用时 515 毫秒
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本文研究了掺杂(B和P)和未掺杂的a-Si1-xCx:H和a-Si1-xNx:H膜在高温下的电子自旋共振(ESR)特性。ESR的测量是在温度连续变化的过程中进行的。实验结果表明:掺B的a-Si1-xCx:H和a-Si1-xNx:H膜的ESR吸收谱,可以分解成两种性质不同的ESR吸收谱的叠加(g1≈2.005和g2≈2.010),g1是硅悬挂键(Si)的贡献,g2是价带尾态定域化空穴的贡献。随温度的上升,定域化空穴的密度比Si下降得更快。在温度不太高时,定域化空穴的密度远大于Si,但在温度较高时,Si的贡献是主要的。
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A detailed numerical study has been made of the convergency of second-and approximate second-order multiconfigurational Hartree-Fock procedures. Calculations were performed on the excited 2p 2 1 S state of Be and on the lowest states of 3Σ g -, 1δ g , 1Σ g +, 1Δ g and 3Δ g symmetry in O2. The O2 calculations included all configurations that could be formed from doubly occupied core orbitals with eight electrons in the valence orbitals, 3σ g , 1π u , 1π g and 3σ u . All second-order calculations converged in between 4 and 6 iterations even for a case where approximate second-order procedures did not converge. 相似文献
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Jitendra Pal Singh R. C. Srivastava H. M. Agrawal Ravi Kumar 《Journal of Raman spectroscopy : JRS》2011,42(7):1510-1517
Zinc ferrite nanoparticles of different sizes ranging from 12 to 62 nm were synthesized by using the nitrate route. These nanoparticles were irradiated by a 100 MeV oxygen beam at two fluences: 1 × 1013 and 5 × 1013 ions/cm2. It was observed that modes corresponding to cubic spinel phase were retained after the irradiation in all the systems. The variation in the parameters of various modes follows phonon confinement, while this effect seems to violate in irradiated specimen. It was found that the irradiation‐induced changes in the modes F2g(2) and F2g(3) depend on whether the crystallite size of the pristine sample is less than, equal to or greater than the phonon confinement length, while this length is not dominant for the irradiation‐induced changes in the mode A1g. The changes in various parameters of the modes are attributed to the combined effect of the restructuring of the chemical species and ion‐induced defects. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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The energy separation of the first excited spin-orbit States Γ3g, Γ4g from the Γ5g ground state, in the orbital 5T2g triplet state of Fe2+ in KMgF3, has been estimated from temperature dependence measurements on the 7860 cm-1 zero-phonon-line (ZPL) transition from Γ5g to the orbital 5Eg doublet state. Using a simplified crystal field energy level model, we find the Γ5g Γ3g, Γ4g separation to be ~30 cm-1, indicating that the vibronic Jahn-Teller coupling is considerably stronger in KMgF3:Fe2+ than in MgO:Fe2+. Far infrared absorption data on KMgF3:Fe2+ in magnetic fields up to 6T, are found to be consistent with this interpretation. 相似文献
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Relativistic energy-consistent small-core lanthanide pseudopotentials of the Stuttgart-Bonn variety and extended valence basis sets have been used for the investigation of some selected lanthanide dimers with open 4f shell, that is Ce2, Pr2 and Gd2. Comparison is made with results of corresponding previous studies of La2 and Lu2 as well as to available experimental data. The trends in the molecular constants of the dimers of the lanthanide series are discussed. The ground state candidates of Ce2(4f14f1σ2 gπ4 u 1Σ+ g, 1Σ? u, 3Σ? g, 3Σ+ u, 16g, 36u) and Pr2(4f24f2σ2 gπ4 u 5Σ+ g, 5Σ? u, 510g) are degenerate within 20cm?1 and have the same valence subconfiguration σ2 g π4 u, which was previously found to give rise to the La2(4f04f0σ2 gπ4 u 1Σ+ g) ground state. In the case of Gd2 the 4f74f7σ2 gσ1 uσ2 u; 19Σ? g ground state found previously is confirmed. The derived molecular constants are the best theoretical estimates available at present and show a satisfactory agreement with experimental data. Discrepancies in the vibrational constants of La2, Ce2 and Pr2 are shown to be probably related to quite large Ar-matrix shifts. 相似文献
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The tightest open conformations of a few prime knots (31, 41, 51, 52, and 63) found with the use of the SONO algorithm are presented and discussed. The conformations are obtained from the tightest closed
conformations of the knots by cutting and opening them at different locations. The length of the rope engaged in each of the
open conformations is calculated. The curvature and torsion profiles of the unique tightest conformations of the 31 and 41 open knots are presented and discussed. In particular, symmetry properties of the knots reflected within their curvature
and torsion profiles are analysed. Connections with the physics of polymers are discussed.
Received 7 March 2001 and Received in final form 17 August 2001 相似文献
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A. M. Kuz’menko A. A. Mukhin V. Yu. Ivanov A. M. Kadomtseva L. N. Bezmaternykh 《JETP Letters》2011,94(4):294-300
Resonance modes that are due to magnetic excitations in the exchange-coupled subsystems of rare-earth ions (R = Nd3+, Sm3+, and Gd3+) and Fe3+ ions have been detected in submillimeter transmission spectra (0.1–0.6 THz) of RFe3(BO3)4 iron borate-multiferroic single crystals. The strong interaction between spin oscillations of the Fe and R subsystems has
been revealed, which determines the behavior of the modes depending on the anisotropy of the exchange splitting of the ground
doublet of the R ion. It has been shown that the intensities of coupled modes (contributions to the magnetic permeability)
depend strongly on the difference between the g factors of Fe and R ions. This dependence makes it possible to determine the sign of the latter g factor. In particular, a noticeable intensity of exchange Nd modes in NdFe3(BO3)4 is due to an increase in their contribution at g
⊥, ‖Nd < 0, while in GdFe3(BO3)4 with g
Gd ≈ g
Fe ≈ 2, the Fe and Gd contributions compensate each other and the exchange (Gd) mode is not observed. In spite of the weak interaction
of Sm ions with the magnetic field, SmFe3(BO3)4 exhibits resonance modes, which are attributed to the excitation of Sm ions through the Fe subsystem. 相似文献
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A. N. Utyuzh 《Physics of the Solid State》2014,56(10):2050-2055
Raman scattering in a natural FeS2 single crystal with the pyrite structure was investigated in the temperature range of 80–300 K. All five Raman-active modes E g , T g (1), T g (2), A g , and T g (3) were observed under normal conditions (T = 23°C). The influence of temperature on the Raman spectra was studied in the HH configurations (polarizations of the incident and scattered radiations are parallel), which made it possible to detect the strongest spectral lines A g and E g . Widths of modes E g and A g were substantially smaller than those given in previous publications. It was found that the temperature dependences of frequencies and widths (FWHM) of modes A g and E g are approximated well by the Klemens model, which describes the three-phonon scattering mechanism. 相似文献