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1.
S.-X. Wang J. Schroderus I. Ozier N. Moazzen-AhmadiV.-M. Horneman V.V. IlyushynE.A. Alekseev A.A. KatrichS.F. Dyubko 《Journal of Molecular Spectroscopy》2002,214(1):69-79
An investigation of the torsion-rotation-vibration energies in the ν5 vibrational state in CH3CF3 has been carried out using infrared and mm-wave spectroscopy. The lowest frequency parallel fundamental band ν5 near 600 cm−1 has been measured at a resolution of 0.00125 cm−1 with Fourier transform spectroscopy for the two lowest torsional states v6=0 and 1. The cold band (v5=1, v6=0)←(v5=0, v6=0) showed no torsional splittings and looked much like a parallel band in a C3v molecule. The hot band (v5=1, v6=1)←(v5=0, v6=1) consisted of three distinct subbands, one for each torsional sublevel σ=0, +1, and −1. For the state (v5=1, v6=1), the torsional splitting was increased from ∼0.001 cm−1 to ∼0.022 cm−1 by torsion-mediated Fermi-type interaction primarily with the dark state (v5=0, v6=5). The effects of this coupling on the spectrum are striking in spite of the fact that the two interacting states are ∼100 cm−1 apart and differ by four units in v6. The large amplitude character of the state (v5=0, v6=5) is seen to be largely responsible for the unusual (k, σ) dependence of the energies in the state (v5=1, v6=1). The pure rotational spectrum in the state (v5=1, v6=0) has been measured between ∼50 and 370 GHz with Doppler-limited resolution; no σ-splitting was detected. The 3590 infrared and mm-wave frequencies measured here have been analyzed together with the 1494 measurements reported earlier by Wang et al. in an analysis of the vibrational ground state (2001, J. Mol. Spectrosc.205, 146-163). A good fit was obtained here by varying 36 parameters in a Hamiltonian which takes into account the interaction between the torsional stacks of levels for v5=0 and 1, as well as the (A1−A2) splittings measured earlier for v5=0. The explicit treatment of the interstack interactions is shown to lead to significant changes in the parameters (V0,3, V0,6) that characterize the torsional potential for v5=0. These changes have been explained quantitatively by examining the contact transformation that is implicitly applied when the interstack coupling is neglected. 相似文献
2.
From the κ symmetric action of IIB string in AdS3×S3 background given by Rahmfeld and Rajaraman, we derive the equations of motion. Then using the twisted dual transformation which was introduced by Hou et al. We construct the flat currents, and hence conserved non-local charge with one free parameter, for the Green-Schwarz superstring in AdS3×S3. Thus we show the AdS3×S3 string is integrable. 相似文献
3.
The influence of hydrothermal modification of γ-Al2O3 on the properties of NiMo/γ-Al2O3 catalyst was investigated in this paper. The experimental results showed that the use of the modified γ-Al2O3 in the preparation of the NiMo/γ-Al2O3 catalyst led to the increase of the dispersion of the surface Mo and Ni oxides, favored the formation of the poly-molybdates and promoted the reduction of the active Mo oxides owing to the increase of the surface acidity of the modified γ-Al2O3. Therefore, the NiMo/γ-Al2O3 catalyst supported on the modified γ-Al2O3 exhibited a higher hydrodenitrogenation (HDN) activity than that supported on the untreated γ-Al2O3 in the temperature range of 300-340 °C. 相似文献
4.
Christophe Lerot Ghislain Blanquet Muriel Lepère 《Journal of Molecular Spectroscopy》2003,217(1):79-86
Using a tunable diode-laser spectrometer, we have measured at room temperature the H2-broadening coefficients of for 36 lines belonging to QP and QR branches in the ν3 parallel band. The recorded lines with J values ranging from 1 to 15 and K from 0 to 9 (K?J) are located between 1196 and 1412 cm−1. The H2-broadening coefficients were determined by fitting each spectral line with Voigt, Rautian, and Galatry profiles. They were also calculated on the basis of a semiclassical model of interacting linear molecules performed by considering in addition to the weak electrostatic contributions the atom-atom Lennard-Jones potential. The theoretical results are in reasonable agreement with the experimental data, except for high J transitions where they are overestimated and for K approaching or equal to J with J?3 where they are underestimated. The latter discrepancy may be caused by the assumption to consider only ΔK=0 collision-induced transitions, associated with |ΔJ| transitions up to 4. 相似文献
5.
Monodisperse Au-Fe 3 O 4 heterodimeric nanoparticles (NPs) were prepared by injecting precursors into a hot reaction solution.The size of Au and Fe 3 O 4 particles can be controlled by changing the injection temperature.UV-Vis spectra show that the surface plasma resonance band of Au-Fe 3 O 4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size.The as-prepared heterodimeric Au-Fe 3 O 4 NPs exhibited superparamagnetic properties at room temperature.The Ag-Fe 3 O 4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO 3 as precursor instead of HAuCl 4.It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs. 相似文献
6.
Relativistic calculations of 3s2 1S0-3s3p 1P1 and 3s2 1S0-3s3p 3P1,2 transition probabilities in the Mg isoelectronic sequence 下载免费PDF全文
Using the multi-configuration Dirac-Fock self-consistent field method and the relativistic configuration-interaction method,calculations of transition energies,oscillator strengths and rates are performed for the 3s 2 1 S 0-3s3p 1 P 1 spinallowed transition,3s 2 1 S 0-3s3p 3 P 1,2 intercombination and magnetic quadrupole transition in the Mg isoelectronic sequence(Mg I,Al II,Si III,P IV and S V).Electron correlations are treated adequately,including intravalence electron correlations.The influence of the Breit interaction on oscillator strengths and transition energies are investigated.Quantum electrodynamics corrections are added as corrections.The calculation results are found to be in good agreement with the experimental data and other theoretical calculations. 相似文献
7.
Yong Liu Ruiqing Chu Zhijun Xu Huiqin Lv Liming Wu Yizheng Yang Guorong Li 《Physica B: Condensed Matter》2012,407(13):2573-2577
Dense K4CuNb8O23 (KCN) modified 0.948K0.5Na0.5NbO3–0.052LiSbO3 (KNNLS) ceramics were prepared by conventional solid state reaction method. The effect of addition of K4CuNb8O23 liquid phase sintering aid on the phase structure and electrical properties of ceramics was studied. Results showed that K4CuNb8O23 induced a perovskite structure transition from coexistence of orthorhombic and tetragonal phases to orthorhombic symmetry. The addition of K4CuNb8O23 promoted the sintering of KNNLS ceramics. In particular, the K4CuNb8O23 addition to the KNNLS greatly improved the mechanical quality factor Qm value. The ceramics with x=0.8 sintered at 1090 °C possess the optimum properties (Qm=192, d33=135 pC/N, tan δ=0.024 and kp=0.357). These results indicate that the ceramic is a promising candidate for lead-free high-power piezoelectric devices, such as piezoelectric actuators, transformers and filter materials. 相似文献
8.
采用磁控溅射,紫外线光刻和离子束刻蚀制备了La2/3Ca1/3MnO3/Eu2CuO4/La2/3Ca1/3MnO3磁性隧道结.通过对获得的磁性隧道结的I-V特性测量,发现非线性的I-V特性,显示结样品的隧穿特性.有趣的是发现在电极材料La2/3Ca1/3MnO3的金属-绝缘体转变温度(Tp)以下,I-V曲线出现一个跳变.随着温度降低,开始出现跳变的临界电流增大,但是跳变都发生在同样的电压下~209mV.当电流增大或减小在跳变点附近出现回滞.这一跳变只发生在铁磁金属态,表明这是一个磁性相关联的效应,可能对应一种新的磁性开关过程.虽然,目前对这一现象背后的物理机理还不清楚,但是,这一现象有可能在未来自旋电子学器件方面具有潜在的应用价值.
关键词:
庞磁电阻
磁性隧道结
开关效应 相似文献
9.
The absorption spectrum of the ν6 band of C2H3D centered near 1125.27674 cm−1 in the 1100-1250 cm−1 region was recorded with an unapodized resolution of 0.0063 cm−1 using a Fourier transform infrared (FTIR) spectrometer. A total of 947 infrared transitions of the A-B hybrid-type band were assigned and fitted to upper-state (ν6 = 1) rovibrational constants using a Watson’s A-reduced Hamiltonian in the Ir representation up to eighth-order centrifugal distortion terms. The b-type infrared transitions of the band were analyzed for the first time. The root-mean-square deviation of the fit was 0.00062 cm−1. The ground-state rovibrational constants up to eighth-order terms were also obtained by a fit of 617 combination differences from the present infrared measurements, simultaneously with 21 microwave frequencies with a root-mean-square deviation of 0.00055 cm−1. From this work, the upper-state (ν6 = 1) and ground-state constants of C2H3D were derived with the highest accuracy, so far. The a- and b-type transitions of the hybrid ν6 band were found to be relatively free from local frequency perturbations. The ratio of the a- to b-type vibrational dipole transition moments (μa/μb) was found to be 1.05 ± 0.10. From the ν6 = 1 rovibrational constants obtained, the inertial defect Δ6 was calculated to be 0.3570 ± 0.0008 μÅ2. 相似文献
10.
Mireya Castillo 《International Journal of Infrared and Millimeter Waves》1992,13(6):909-922
A FT-IR spectroscopic study was carried out in the region 4000–400 cm–1 for ZnSeNi and ZnSNi at room temperature. The data obtained were examined on the basis of the energy states calculations of the (3d)n configuration, based on the defect molecule approach. The present investigation reveals the transition from the ground state to the first two excited states namely3T1–3A2 and3T1–3T2 of Ni+2 (d8). 相似文献
11.
Gurinder Pal Singh Parvinder KaurSimranpreet Kaur D.P. Singh 《Physica B: Condensed Matter》2012,407(21):4168-4172
xCeO2–30Bi2O3–(70−x) B2O3 glasses are synthesized by using the melt quench technique. A number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.15 to 1.61 eV, refractive index increases from 2.67 to 2.93 and density increases from 4.151 to 4.633 g/cm3. The decrease in band gap with CeO2 doping approaches the semiconductor behavior. FTIR spectroscopy reveals that incorporation of CeO2 into glass network helps to convert the structural units of [BO3] into [BO4] and results in Bi–O bond vibration of [BiO6]. 相似文献
12.
Based on density functional theory+U calculations and the quasi-annealing simulation method, we obtain the ground electronic state for α-Pu2O3 and present its phonon dispersion curves as well as various thermodynamic properties, which have seldom been theoretically studied because of the huge unit cell. We find that the Pu–O chemical bonding is weaker in α-Pu2O3 than in fluorite PuO2, and subsequently a frequency gap appears between oxygen and plutonium vibration density of states. Based on the calculated Helmholtz free energies at different temperatures, we further study the reaction energies for Pu oxidation, PuO2 reduction, and transformation between PuO2 and α-Pu2O3. Our reaction energy results are in agreements with available experiment. And it is revealed that high temperature and insufficient oxygen environment are in favor of the formation of α-Pu2O3. 相似文献
13.
I.V. VasylenkoS.V. Kolotilov I.E. KotenkoK.S. Gavrilenko F. TunaG.A. Timсo R.E.P. WinpennyV.V. Pavlishchuk 《Journal of magnetism and magnetic materials》2012,324(4):595-601
Thermal decomposition of the trinuclear complex [Fe2CrO(CH3COO)6(H2O)3]NO3 at 300, 400 and 500 °C gave γ-Fe2O3 nanoparticles along with amorphous chromium oxide, while decomposition of the same starting compound at 600 and 700 °C led to the formation of α-(Fe2/3Cr1/3)2O3 nanoparticles. Size of γ-Fe2O3 nanoparticles, determined by X-ray diffraction, was in the range from 9 to 11 nm and increased with formation temperature growth. Average size of α-(Fe2/3Cr1/3)2O3 nanoparticles was about 40 nm and almost did not depend on the temperature of its formation. γ-Fe2O3 nanoparticles possessed superparamagnetic behavior with blocking temperature 180-250 K, saturation magnetization 29-35 emu/g at 5 K, 44-49 emu/g at 300 K and coercivity 400-600 Oe at 5 K. α-(Fe2/3Cr1/3)2O3 nanoparticles were characterized by low magnetization values (2.7 emu/g at 70 kOe). Such magnetic properties can be caused by non-compensated spins and defects present on the surface of these nanoparticles. The increase of α-(Fe2/3Cr1/3)2O3 formation temperature led to decrease of magnetization (being compared for the same fields), which may be caused by decrease of the quantity of defects or non-compensated spins (due to decrease of particles' surface). 相似文献
14.
A. T. Kozakov A. V. Nikol’ski? V. P. Sakhnenko A. N. Pavlov V. G. Smotrakov V. V. Eremkin 《Physics of the Solid State》2009,51(7):1385-1389
Spectra of anomalous electron emission from the surface of solid solutions in the (1 − x)PbMg1/3Nb2/3O3 + xPbTiO3 system with x = 0.06, 0.10, 0.13, 0.20, and 0.25 have been studied. While the energy characteristics of the anomalous electron emission
spectra vary monotonically with x, the behavior of integrated intensity was found to be nonmonotonic with a maximum occurring at x = 0.1. According to the proposed interpretation, the results obtained are explained by the effect of the potential barrier
on the electron emission; the potential barrier depends, in turn, on the permittivity ε of the samples.
Original Russian Text ? A.T. Kozakov, A.V. Nikol’skiĭ, V.P. Sakhnenko, A.N. Pavlov, V.G. Smotrakov, V.V. Eremkin, 2009, published
in Fizika Tverdogo Tela, 2009, Vol. 51, No. 7, pp. 1310–1314. 相似文献
15.
The second overtone band 3ν1 of sulfur dioxide has been studied for the first time with high resolution rotation-vibration spectroscopy. About 3000 transitions involving about 900 upper state energy levels with have been assigned to the 3ν1 band. In the analysis, an effective Hamiltonian taking into account accidental interactions between the vibrational states (3 0 0), (2 2 0), and (0 4 1) was used. The Watson operator in A-reduction and Ir representation was used in the diagonal blocks of the Hamiltonian. As the result of analysis a set of parameters reproducing the initial experimental data with the rms = 0.00028 cm−1 was obtained. 相似文献
16.
N. V. Kazak N. B. Ivanova V. V. Rudenko A. D. Vasil’ev D. A. Velikanov S. G. Ovchinnikov 《Physics of the Solid State》2009,51(5):966-969
Ludwigite single crystals of compositions Co3O2BO3 and Co3 − x
Fe
x
O2BO3 (x ≈ 0.14) have been synthesized. The crystal structure is investigated at room temperature, and the magnetization is studied
in the temperature range T = 4.2–100 K in magnetic fields of up to 600 Oe. The orthorhombic symmetry is revealed, and the unit cell parameters are determined.
A number of features are established for the temperature dependence of the magnetization. In unsubstituted Co3O2BO3, two magnetic transitions are found at T
C1 = 43 K and T
C2 = 15 K. At temperatures below 40 K, spin-glass state is revealed. Substitution of iron ions for cobalt ions leads to a noticeable
shift in the magnetic transitions toward the high-temperature range: T
C1 = 83 K and T
C2 = 74 K. A ferromagnetic ordering of the P type is found in the Co3 − x
Fe
x
O2BO3 (x ≈ 0.14) compound.
Original Russian Text ? N.V. Kazak, N.B. Ivanova, V.V. Rudenko, A.D. Vasil’ev, D.A. Velikanov, S.G. Ovchinnikov, 2009, published
in Fizika Tverdogo Tela, 2009, Vol. 51, No. 5, pp. 916–919. 相似文献
17.
Yosun HwangS. Angappane Jongnam ParkKwangjin An T. HyeonJe-Geun Park 《Current Applied Physics》2012,12(3):808-811
We have carried out systematic studies on well-characterized monodisperse Fe3O4/γ-Fe2O3 core/shell nanoparticles of 2-30 nm having a very narrow size distribution and possessing a uniquely mono-layer of surface γ-Fe2O3. This unique core-shell structure, probably having a disordered magnetic surface state, leads us to three key observations of unusual magnetic properties: i) a very large magnetic exchange anisotropy reaching over 7 × 106 erg/cm3 for the smaller particles, ii) exchange bias behavior in the magnetization data of the core/shell Fe3O4/γ-Fe2O3 nanoparticles, and iii) the temperature dependence of the coercive field following an unusual exponential behavior. 相似文献
18.
The ν3 fundamental band (CO stretch) of HDCO at 1724 cm?1 has been studied using both conventional infrared absorption and CO laser Stark spectroscopy. In addition to the excited-state (v3 = 1) rotational constants, improved constants for the ground state of HDCO have been obtained by combining previous microwave data with some infrared combination differences. The following constants were determined:
Constant | Ground state | state | Units |
1724.267 | cm?1 | ||
198 119.75 | 198 210.4 | MHz | |
34 910.646 | 34 676.6 | MHz | |
29 561.488 | 29 331.3 | MHz | |
2.3302 | 2.3486 | D | |
0.195 | 0.190 | D |