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M. R. DE BACKER-BARILLY A. BARBE S. A. TASHKUN VL. G. TYUTEREV A. CHICHERY 《Molecular physics》2013,111(22):3499-3506
The four 5v 3 bands of 18O enriched ozone have been observed and analysed for the first time. Two species (16O18O16O and 18O16O18O) belong to the C2v symmetry group and two other (18O18O16O and 16O16O18O) to the Cs symmetry group. They have been recorded at a resolution of 0.008 cm?1 with a pathlength of 32.16 m. Despite the very weak absorptions observed, almost 250 energy levels have been derived for each of the 4 species, with J ? 35 and K a ? 13, and suitable sets of Hamiltonian parameters have been determined. For 3 species it has been necessary to account for the resonance between the (005) and (311) states to correctly reproduce the spectra observed. These resonances, anharmonic for C2v, and hybrid (both anhar-monic and Coriolis) for Cs symmetry confirm the accidentally extremely strong coupling between the (005) and (311) states for 16O3, due in that case to the very close distance between unperturbed energy levels. This work also confirms the excellent prediction of band centres of these four species derived from the recently determined isotopically invariant molecular potential function. 相似文献
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D. A. Kirzhnits 《Theoretical and Mathematical Physics》1993,96(3):1027-1034
For the example of the nonrelativistic Schrödinger operator, methods are formulated for calculating the determinant of an elliptic operator on the basis of scattering theory. It is shown that such a determinant is identical to the Jost determinant at zero energy. In the centrally symmetric case, it reduces to ordinary Jost functions and ultimately to the values of the zero-energy wave functions at the origin. The relationship between the determinant of the Schrödinger operator and the characteristics of the scattering resonances and the number of bound states in a field of opposite sign is noted. This makes it possible to find the first terms in the gradient expansion of the determinant as a functional of the potential. The problem of the correlation free energy of a classical plasma serves as a physical illustration.P. N. Lebedev Physics Institute, Russian Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 96, No. 3, pp. 373–384, September, 1993. 相似文献
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This article is a brief review of the present situation in theoretical investigations of high temperature superconductivity. The main subject is a discussion of the formula for a critical temperature Tc for a homogeneous and isotropic substance with arbitrary permeability ?(q, ω). The problem of the maximum possible value of Tc is discussed. It is concluded that at present there are no grounds to consider that values of Tc ? 100°K to be impossible. The paper ends with some remarks on the exciton mechanism of superconductivity for the case of superconductors with a plane geometry. 相似文献
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S.N. Mikhailenko VL.G. TyuterevV.I. Starikov K.K. AlbertB.P. Winnewisser M. Winnewisser G. MellauC. Camy-Peyret R. LanquetinJ.-M. Flaud J.W. Brault 《Journal of Molecular Spectroscopy》2002,213(2):91-121
Water vapor infrared spectra have been recorded at room temperature in the range 4200-6250 cm−1 at resolutions (FWHM) between 0.0053 and 0.0080 cm−1. The use of a White-type multireflection cell made large pressure × pathlength products possible up to 31.27 mbar×288.5 m. The high signal-to-noise ratio allowed us to observe lines with intensities as small as 10−26 cm−1/molecule cm−2 at T=296 K. Among about 5100 recorded water lines, about half of which are reported for the first time, 2351 lines have been assigned to the second triad of H216O (bands ν1+ν2, ν2+ν3, and 3ν2). This has allowed the determination of line positions and corresponding upper rovibrational states with considerably improved accuracy. The assignments of certain highly excited states have been confirmed by the analysis of flame spectra and hot emission spectra. New values of effective Hamiltonian parameters for the upper states {(110), (030), (011)} have been determined. The generating function model was used in the data reduction to account for the anomalously strong centrifugal distortion of the rovibrational levels and resonance interactions. The RMS standard deviation of the least-squares fit of the assigned H2O data was 5×10−3 cm−1 for line positions and 7×10−3 cm−1 for energy levels up to Jmax=20 and Ka(max)=13. Particular attention was paid to water lines in the transparency window 4200-5000 cm−1, in which existing databases are not sufficient. In this region, 1395 lines of four isotopic species of water have been recorded and over 900 accurate line positions of nine bands of H216O (ν1, ν3, 2ν2, ν1+ν2, ν2+ν3, 3ν2, 4ν2−ν2, 2ν2+ν3−ν2, ν1+2ν2−ν2) are reported in this range. A comparison of laboratory spectra with long path atmospheric spectra (20 km slant path in the mountains) in this region shows that many lines missing from available spectroscopic compilations (or considerably shifted compared to observations) are important for a proper interpretation of atmospheric observations. A comparison of the observed data with the best available predictions from the molecular electronic potential energy surface is discussed. 相似文献
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Stability radii for some propagation models 总被引:2,自引:0,他引:2
The simple idea of Hinrichsen & Pritchard who defined thestructured stability radius has proved to be unexpectedly fruitful,generating a large amount of work and making interesting connections.The aim of this paper is twofold: to study stability radii forsome specific propagation models and to make connections withresults on Popov-type frequency-domain stability inequalities. 相似文献
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Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
x
La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献