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一般教材中,在讨论一维弦线中的横波波动方程时,都假设弦线中的张力为恒量,在小扰动情况下,推导横波波动方程,本文在较一般情况下,推导一维弦线中的横波波动方程,并讨论弦线中张力的变化等问题,所得结果在小扰动近似下,与一般教材中的结论一致。 相似文献
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在考虑NO分子的(5σ)^2(1π)^43P-(5σ)^2(1π)^3(2π)^2构形相互作用的情况下,对D^2Σ,C^2Ⅱ,B^2Ⅱ和L^2Ⅱ电子态的转动能级结构以及态函数进行了计算,计算结果与实验结果很相符。 相似文献
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Charged species structurally related to several isomers of Cl(2)O(2), of considerable importance in atmospheric chemistry, were obtained by chemical ionization (CI) and characterized by collisionally activated dissociation (CAD) mass spectrometry. The ClOClO(+) and [Cl(2)-O(2)](+) species were prepared by positive ion Cl(2)/CI of ClO(2) and O(2), respectively, whereas the ClClO(2)(+) isomer proved an elusive species of considerably lower stability. The ClClO(2)(-) anion was obtained from the negative ion Cl(2)/CI of ClO(2). The formation process, structure and stability of the ions are discussed in connection with available theoretical results and related to the recent preparation of (Cl(2)O(2))(+)SbF(6)(-) and (Cl(2)O(2))(+)Sb(2)F(11)(-) salts in the solid phase. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Dynamic behavior of the pH-regulated oscillations has been studied for the hydrogen peroxide oxidation of thiosulfate ions in the presence of trace amounts of copper(II) ions in a semibatch reactor. A solution of 0.08 M Na(2)S(2)O(3) and 0.112 M NaOH was flowed at 0.160 mL/min into 300 mL of solution containing the H(2)O(2) and Cu(2+) in a vessel. There exists a critical value of the H(2)O(2) or Cu(2+) concentrations below which the system does not oscillate. The oscillations appear due to an infinite period bifurcation at low initial concentrations of the H(2)O(2). The initial concentration of Cu(2+) may be considered as a bifurcation parameter in this case. Increase of the initial hydrogen peroxide concentration causes the pH-regulated oscillations through a nondegenerate supercritical Hopf bifurcation. The classification of bifurcations is based on the analysis of the behavior of oscillation amplitude and period at different initial concentrations of the H(2)O(2) and Cu(2+). Our results show a possibility to distinguish different scenarios for the appearance of transient oscillations in semibatch experiments. (c) 1996 American Institute of Physics. 相似文献
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The double vibrational collision-induced absorptions CO(2) (nu(3) = 1) + X(2) (nu(1) = 1) <-- CO(2) (nu(3) = 0) + X(2) (nu(1) = 0), for X(2) = H(2), N(2), and O(2) are studied on the basis of quantum lineshapes computed using isotropic potentials and dipole-induced dipole functions. The linestrengths and energies of the vibration-rotation transitions are treated explicitly for X(2) and utilizing the HITRAN database for CO(2). From the frequency-dependent absorption profiles, the integrated absorption intensities are determined to be 7.2 +/- 1.2, 1.2 +/- 0.1, and 1.1 +/- 0.2 (10(-4) cm(-2) amagat(-2)) for the H(2), N(2), and O(2) collision partners, respectively. The integrated intensities for H(2) and N(2) agree well with previously measured and calculated results, while the value for O(2), which represents the first theoretical determination for this absorption, is approximately four times greater than the only experimental measurement (0.29 x 10(-4) cm(-2) amagat(-2)). Copyright 2001 Academic Press. 相似文献
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High-resolution Fourier transform infrared spectrum of the nu(2) band (1590-1780 cm(-1)) of deuterated formaldehyde D(2)CO has been recorded. More than 2500 rovibrational transitions have been assigned up to J(max) = 52 and K(max)(a) = 17. The upper state v(2) = 1 (A(1)) was found to be perturbed by a DeltaK(a) = 2 interaction with the v(4) = 2 (A(1)) state. To explain the resonance perturbation in the v(2) = 1 state, some lines of the 2nu(4) band (the band center at about 1868 cm(-1)) have also been assigned. Both bands were fitted simultaneously to the Watson-type rotational Hamiltonian using I(r) representation in A reduction, and the mutual interaction was taken into account. As a result, the rotational parameters of the v(2) = 1 state up to eighth order and the interaction parameter have been obtained. Copyright 2001 Academic Press. 相似文献
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The microwave spectra of N(2)-O(3) and N(2)-SO(2) have been recorded in the 6-18 GHz range using a pulsed-nozzle, Fourier transform microwave spectrometer. C-type transitions have been observed for both complexes which are slightly shifted by internal tunneling motions of the O(3) or SO(2) moieties. In addition, unshifted a-type transitions have been observed for N(2)-O(3). The nuclear hyperfine pattern is typical of equivalent nitrogen nuclei. Two sets of rotational and hyperfine constants are required to fit the symmetric and antisymmetric nuclear spin states, indicating that the equivalence arises from tunneling rotation of the nitrogen molecule. Internal tunneling motions along three tunneling pathways have been identified, although no information on the N(2) tunneling frequency is available from the spectra. From the N(2)-O(3) data the tunneling frequencies cannot be decorrelated from the rotational parameters; however, the O(3) tunneling frequency upper limit is estimated to be 2.0 MHz and the frequency of the concerted tunneling motion of both moieties is estimated to be about 8.9 MHz. For N(2)-SO(2), the SO(2) tunneling frequency is 11.5 kHz and the concerted frequency 173.9 kHz. Both complexes are roughly T shaped with the N(2) axis approximately perpendicular to the O(3) or SO(2) plane. In the equilibrium structures of both complexes, the a-c inertial plane is a plane of symmetry. The centers of mass separations are estimated from the rotational parameters to be 3.582 ? for N(2)-O(3) and 3.875 ? for N(2)-SO(2). The angle between the symmetry axes of the O(3) or SO(2) and the line joining their centers of mass have been calculated as 130.84 degrees (or 49.16 degrees ) and 119.71 degrees (or 60.29 degrees ), respectively. From the quadrupole analysis, the average angle between the N(2) axis and the a-inertial axis is 32.12 degrees for N(2)-O(3) and 27.81 degrees for N(2)-SO(2). Model electrostatic and ab initio calculations confirm these structures. Differences between the experimental and calculated structural parameters highlight the role of tunneling dynamics in these complexes. Copyright 2000 Academic Press. 相似文献
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Dai X Clevenger JO Liu Y Song M Shang J Chen D Field RW Li L 《Journal of Molecular Spectroscopy》2000,200(1):120-122
Using pulsed perturbation-facilitated optical-optical double resonance (PFOODR) spectroscopy, the 2(3)Delta(g) state of (7)Li(2) (electronic configuration (varsigma(g)2s) (4ddelta(g)), effective principal quantum number n* = 4.101) has been observed and assigned. Molecular constants and a RKR potential energy curve were obtained. The major molecular constants are Copyright 2000 Academic Press. 相似文献
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We report calculated values of isotope fractionation factors between chlorine, bromine and sulphide hydrated anions and respective gaseous compounds: hydrogen chloride, hydrogen bromide, molecular chlorine and bromine and hydrogen sulphide. For the calculation of the reduced partition function ratios (β-factors) of hydrated Cl(-), Br(-) and S(2-) anions, we used a model of a cluster composed of the considered ion surrounded by two shells of H(2)O molecules. Only the electrostatic interaction between ion and water molecules treated as electric dipoles was taken into account. The β-factors for the gaseous compounds (HCl, Cl(2), HBr, Br(2) and H(2)S) were calculated from vibrational frequencies reported by Urey and Greiff [Isotopic Exchange Equilibria, J. Am. Chem. Soc. 57, 321 (1935)] and Schauble et al. [Theoretical Estimates Equilibrium Chlorine-Isotope Fractionation, Geochim. Cosmochim. Acta 67, 3267 (2003)]. Low-temperature isotope fractionation between chlorine-hydrated anion and hydrogen chloride attains 1.55-1.68‰ (this work), which is in good agreement with experimental data (1.4-1.8‰) [Z.D. Sharp, J.D. Barnes, T.P. Fischer and M. Halick, An Experimental Determination of Chlorine Isotope Fractionation in Acid Systems and Applications to Volcanic Fumaroles, Geochim. Cosmochim. Acta 74, 264 (2010)]. The predicted isotope fractionations for hydrated bromine and HBr, Br(2) gases are very small, 1000?ln α, do not exceed 0.8‰; thus, the expected variations of bromine isotope composition in aqua-gas systems will require enhanced precision for their detection. In contrast, the sulphur isotope fractionation between H(2)S( gas ) and S(2-) attains 6.0‰ at room temperature and drops nearly linearly to 3.1‰ at 350°C. 相似文献
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A procedure is presented for the calculation of the double vibrational collision-induced absorption CO(2) (nu(3) = 1) + N(2) (nu(1) = 1) <-- CO(2) (nu(3) = 0) + N(2) (nu(1) = 0) on the basis of quantum lineshapes computed using an isotropic potential and dipole-induced dipole functions. The linestrengths and energies of the vibration-rotation transitions are treated explicitly for N(2), utilizing the HITRAN database for CO(2). The theoretical absorption profile is compared to recent experimental results. By narrowing the width of the individual lines contributing to the overall absorption profile relative to their values determined for N(2)-N(2) collision-induced absorption, excellent agreement between theory and experiment is obtained. Copyright 2000 Academic Press. 相似文献
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The vortex-matter 3D to 2D phase transition is studied in micron-sized Bi(2)Sr(2)CaCu(2)O(8 + delta) single crystals using local Hall magnetization measurements. At a given temperature, the second magnetization peak, the signature of a possible 3D--2D vortex phase transition, disappears for samples smaller than a critical length. We suggest that this critical length should be equated with the 2D vortex lattice ab-plane correlation length R(2D)(c). The magnitude and temperature dependence of R(2D)(c) agree well with Larkin-Ovchinnikov collective pinning theory. 相似文献