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1.
Matrix elements are derived for both first- and second-order Coriolis interactions between A1 and E1 vibrational modes in symmetric tops, with particular reference to sign. The results are applied to the observed microwave transitions JJ + 1 for A1 and E1 states of the C5ν molecule cyclopentadienyl thallium in various excited vibrational states. The microwave transitions in the excited A1 states v4 = 1, 2, 3, the excited E′ state v0 = 1 and the combination state v4 = 1, v0 = 1 have yielded constants which are anomalous in several respects (1). Coriolis interactions between the ν4 and ν10 vibrations are shown to account for the observed anomalies.  相似文献   

2.
3.
The original theory of a proximity effect is proposed for the bi- and tri-layered system ferromagnetic metal/superconductor (F/S) in dirty limit. The F1/S/F2 trilayer is examined more closely. The distinctions in materials, in thicknesses of F layers (df1 and df2), in parameters interfaces, and in local environments of layers are considered among the causes of incommensurability of trilayer. The peculiar Tc(df1, df2) interference pattern is predicted for the F1/S/F2 systems. The reentrant superconductivity and possibility of the better observability of the spin-valve regime are discussed.  相似文献   

4.
Dispersion relations of phonons are obtained in the harmonic approximation for the two-dimensional Wigner crystal under the magnetic field. For small wave vector, the eigen-energies of two modes are ω+ = ωc = eH/mc and ω?ωlωt/ωc, where ωl and ωt are frequencies of longitudinal and transverse phonons in the absence of the field.  相似文献   

5.
The infrared perpendicular bands ν9 and ν10 in allene-d4, which are located at 824 and 666 cm?1, respectively, have been studied at a resolution near to 0.010 cm?1. The bands were analyzed by taking into account the z-Coriolis resonance between these bands and the (x,y)-Coriolis resonance between ν10 and ν4(B1), which is only Raman active. Upper-state parameters and interaction constants are derived from this analysis. Additional Coriolis interactions between ν9 and ν3(A1) as well as between ν10 and 2ν112(B1,B2) are also discussed. Special attention is paid to the study of l-type doublings. Doublets due to q(?) doubling were resolved both in ν9 and in ν10. l-type doubling constants including their signs are also obtained.  相似文献   

6.
Models consistent with the scaling theory of critical phenomena and capable of describing the thermodynamic properties F of substances on the coexistence curve, such as the density of the liquid ρ l , density of the gas ρ g , order parameter f s , mean coexistence curve diameter f d , and saturation pressure P s are discussed. The models are presented in the form of equations F = (τ, D, C), where τ = (T c ? T)/T c , and D = (α, β, T c , ρ c , P c , ...) are the critical characteristics, such as T c , ρ c , and P c (temperature, density, and pressure, respectively), α and β are the scaling exponents, and C are adjustable coefficients. The authors developed combined models f(τ, D, C) for describing the indicated properties of a number of compounds (CH4, NH3, SF6, water, methanol, ethanol, diethyl ether, and freons R134a, R143a, and R236ea). The coefficients C were determined based on experimental data over a wide temperature range, including the critical point. The equations derived are used to perform practical calculations, including estimates of the first and second derivatives of the saturation pressure with respect to the temperature in the critical region.  相似文献   

7.
For the Fe pnictide superconductors, band features important for superconductivity (SC) in the neighborhood of εF are mimicked by tight-binding bands with bases of Fe dxz, dyz and dxy orbitals. In terms of this 3-band model, effective pair transfer processes originating from Coulombic integrals are shown to be largely enhanced due to the nesting between electron and hole pockets by explicitly summing up ladder diagrams. Obtained coupled gap equations lead to s±-type SC. This framework are argued to provide a scheme for discussing important elements working for the high Tc SC, although its validity is restricted to the case where Dirac cones are away from εF. Experimental results on Fe pnictides are discussed in terms of the present results. The pair transfer process explicitly due to the exchange-like integral is suggested to be considerably important for the high Tc in MFeAsO1−xFx to occur.  相似文献   

8.
Two components of superposition single-photon state are entering into two different ports of multiport interferometer. Interference effects in which the inputs into the interferometer are controlling the outputs are studied. In particular we study a multiport beam-splitter (BS) configuration, in which eight input operators a0, a1, a2a7 are mixed by 12 BS's to produce the output operators b0, b1, b2b7. Multiport beam-splitter transformations of superposition single-photon states are analyzed with a possible use of postselection effects.  相似文献   

9.
The angular, temperature, and magnetic field dependences of the resistance recorded in the Hall effect geometry are studied for the rare-earth dodecaboride Tm1 ? x Yb x B12 solid solutions where the metal-insulator and antiferromagnetic-paramagnetic phase transitions are observed in the vicinity of the quantum critical point x c ?? 0.3. The measurements performed on high-quality single crystals in the temperature range 1.9?C300 K for the first time have revealed the appearance of the second harmonic contribution, a transverse even effect in these fcc compounds near the quantum critical point. This contribution a is found to increase drastically both under the Tm-to-ytterbium substitution in the range x > x c and with an increase in the external magnetic field. Moreover, as the Yb concentration x increases, a negative peak of a significant amplitude appears on the temperature dependences of the Hall coefficient R H(T) for the Tm1 ? x Yb x B12 compounds, in contrast to the invariable behavior R H(T) ?? const found for TmB12. The complicated activation-type behavior of the Hall coefficient is observed at intermediate temperatures for x ?? 0.5 with activation energies E g /k B ?? 200 K and E a/k B = 55?C75 K, and the sign inversion of R H(T) is detected at liquid-helium temperatures in the coherent regime. Renormalization effects in the electron density of states induced by variation of the Yb concentration are analyzed. The anomalies of the charge transport in Tm1 ? x Yb x B12 solid solutions in various regimes (charge gap formation, intra-gap many-body resonance, and coherent regime) are discussed in detail and the results are interpreted in terms of the electron phase separation effects in combination with the formation of nanosize clusters of rare earth ions in the cage-glass state of the studied dodecaborides. The data obtained allow concluding that the emergence of Yb-Yb dimers in the Tm1 ? x Yb x B12 cage-glass matrix is the origin of the metal-insulator transition observed in the achetypal strongly correlated electron system of YbB12.  相似文献   

10.
The effects of polymers doping on irreversibility field (Hirr) and critical current density (Jc) of MgB2 have been investigated in this work. It is found that both Jc, and Hirr, are improved by doping at relative lower temperature region. The JcB curves of all samples studied in this work are well fitted using Jc(B) formula in percolation model. The values of upper critical field anisotropy (γ) are obtained from the fitting result at various temperatures. It is observed that values of γ for polymers doping samples are reduced at these temperatures. This is considered to be responsible for the enhancement of values of Jc for doped samples. Moreover, the percolation threshold, pc, is found to be enhanced with increasing temperature. It is believed that the grain boundary pinning is still dominating in MgB2, while the deviation of experimental data from the theoretical values is due to the percolation of suppercurrent in polycrystalline MgB2.  相似文献   

11.
In the insulating compounds MnPSe3 (1) and FePSe3 (2) the divalent transition metal ions form planar honeycomb lattices. A neutron diffraction study revealed a collinear antiferromagnetic order below TN = 74 ± 2 K (1) and TN = 119 ± 1 K (2) with the corresponding wavevectors k = [000] (1) and k = [12 0 12] (2). In MnPSe3 the magnetic moments (m0 = 4.74 μB) lie within the basal plane and in FePSe3 (m0 = 4.9 μB) they are pointing along the c-axis. The collinear structures are determined by the dominating intralayer interactions between first (J1), second (J2) and third neighbours (J3) which in MnPSe3 are all antiferromagnetic whereas in FePSe3J1 is ferromagnetic and J2 and J3 are antiferromagnetic.  相似文献   

12.
A computer model is presented for predicting traffic noise indices in built-up situations for free flow traffic conditions and for a flow interrupted by a traffic light. The stream of vehicles is simulated by a given time headway distribution, and a transfer function obtained from a 1 : 100 scale model is used to simulate the specific built-up situation. Different time headway distributions result in only very small discrepancies; even the simple “equally spaced” distribution is adequate for predicting noise indices with high accuracy, unless L90 has to be predicted. In eight built-up situations along a road with freely flowing traffic only minor mutual differences are found when L1 ? Leq and L10 ? Leq are compared, but L50 and L90, and consequently TNI and Lnp, show discrepancies of the order of 10 dB(A). If a traffic light is introduced the value of Leq rises compared with the free flow case, and the values of L1 and L10 increase, especially at higher traffic intensities, while L50 and L90 decrease. If the noise indices are calculated as a function of the distance along the road to the traffic light increases in L1, L10 and Leq are found at about 50 m beyond the traffic light. The principal cause for this increase appears to be the differences between the peak levels of an accelerating car and the sound level at the ultimate speed. More in situ measurements are required to test the accuracy of the model, especially for accelerating vehicles.  相似文献   

13.
The supporting details for assignment of band maxima (see paper I) in the one-photon 1B2u1A1g absorption spectra of benzene vapor are given. By the criteria of band separations and Franck-Condon intensities, maxima are first sorted into ν1 progressions (Table II). The progressions are then assigned by systematic search for allowed first-, second-, and third-order Herzberg-Teller transitions as set forth in Table II of Paper II. Much attention is given to vibrational angular momentum as it affects band contours and component splittings. Over 90% of the intensity is assigned and a consistent pattern of Herzberg-Teller activity is found. Both the list of modes observed to be active in vibronically inducing the transition (ν4, ν5, ν6, ν7, ν9, ν10, ν11, ν16, ν17) and the relative intensities of various types of transitions found in absorption match well that seen in SVL fluorescence. Third-order transitions are comparatively few in number, but are equivalent in intensity to many second-order transitions. Variation in the separation between progression members suggests that small (and unidentified) perturbations of upper state vibronic levels are ubiquitous. Revised or new values of nine fundamentals in the 1B2u state and two in the 1A1g state are given (Table IV). Some of the excited and ground state anharmonic constants xi0, xi,i0, xi,j0, gi,i, and gi,j are deduced for ν5, ν6, ν10, ν11, ν16, and ν17 (Table V).  相似文献   

14.
The investigation of the problem of embedding a semi-simple real Lie algebra L′ in a non-compact semi-simple real Lie algebra L is extended to the case in which at least one of the real Lie algebras has a semi-simple complex extension, which consists of the direct sum of two simple complex Lie algebras. Detailed procedures are given, which together with those given previously, allow the construction of all embeddings of L′ in L when their complex extensions are A1, B1, C1, D1 or a direct sum of any two of these. The procedures are illustrated by considering examples corresponding to complex Lie algebra embeddings A1?(A2A2), (A1A1)?(A2A2), (A1A1)?A3, (A1A1)??(A3A3) and (A1A1)?(A3A2). Because of its physical significanc embeddings of SL(2,C) in simple and semi-simple real Lie algebras are studied in detail.  相似文献   

15.
The fully relativistic transition probabilities in atomic X-ray emission are calculated for a wide range of selected elements of the periodic table, fromZ=21 toZ=93. The treatment includes the effect of the retardation of the radiation field. The atomic model used is the self-consistent relativistic Hartree-Fock, with the Slater approximation for the exchange term. The formulas for EL and ML multipole transition rates are derived, and transition rates are calculated for all transitions to theK-shell,L-subshells, andM-subshells. The contributions of all multipoles, as determined by the angular momentum and parity selection rules, are included in the present work. The calculated values of ( 2/ 1), ( 1/ 1), ( 3/ 1) and ( 2 1) transition rates are in good agreement with the available experimental data. Rates for the forbidden (M1) 2s 1/2→1s 1/2 transitions are also presented.  相似文献   

16.
Variations in the unit cell occupancy of TiCxOy phase are considered in terms of successive oxygen inclusion into the lattice of defect carbides TiC0.5 ? TiC0.9. A classification of TiCxOy solid solutions formed and the concentration limits of their existence are presented. Three types of cubic ternary solid solutions are shown to occur in the system TiCO: solid solutions of interstitial oxygen inclusion into the initial carbide; solid solutions of oxygen inclusion—carbon and metal exclusion; and solid solutions of oxygen inclusion—oxygen substitution for carbon-carbon and metal exclusion.Specific points (inflection and breaks) on the plots where ni is the number of atoms per unit cell, ni = f(y) for TiCxOy, are accounted for by both variations in the type of solid solution and the possibility of atomic arrangement in the vicinity of these points. On the basis of the above scheme some experimental peculiarities of Ti carbide phase oxydation are explained.  相似文献   

17.
We consider a quatenary semiconductor compound, (A1?uBu)1?y(C1?vDv)y, in which the A and B atoms occupy sites in one sublattice. the C and D atoms occupy sites in a second sublattice, and for which y is always near 12. A statistical thermodynamic analysis for a specific defect model gives three independent “stoichiometry invariants” for the chemical potentials, e.g. μB + μD, μA ? μB, and μC ? μD, which are independent of approximation for small ratios of defect to site concentration. This result is independent of the specific defects chosen, but is obtained under the assumptions that the distribution of the A and B atoms among themselves and that of C and D atoms among themselves are random. A more general analysis that removes these assumptions still yields the same stoichiometry invariants. These invariants provide simple, model-independent relations among the chemical potentials that are extremely useful and to some extent already employed. They also provide the basis for a check on internal self-consistency when all the chemical potentials are measured. The analogous results for a ternary compound are readily extracted as a special case.  相似文献   

18.
T. Tél 《Physics letters. A》1983,94(8):334-336
We present an equation describing invariant curves associated with periodic points of period two in a wide class of two-dimensional invertible maps. Several branches of the unstable manifolds for the map xn+1 = 1 - a|xn| + bzn, zn+1 = xn are constructed in a situation when they are related to a two-piece strange attractor.  相似文献   

19.
Model concepts of the interphase boundaries whose displacements are capable of substantially affecting the piezoelectric properties of xPbTiO3-(1?x)Pb(Zn1/3Nb2/3)O3 multidomain crystals in the R3m-P4mm morphotropic region are developed. The contributions of the interphase boundaries Δd 33 to the piezoelectric modulus d 33 are determined, and the factors responsible for the large ratios Δd 33/d 33≈0.5–0.9 are analyzed.  相似文献   

20.
V.M. Fitio  T.N. Smirnova 《Optik》2008,119(5):236-246
Diffraction by a thick transmission phase grating being illuminated by a plane wave at the first, second and third Bragg angles is analyzed using the rigorous coupled-wave theory for the materials having a nonlinear response to the holographic illumination. It is shown that in the case of nonlinear holographic recording the two-wave approximation can be applied with the use of the effective value of the amplitudes of the refractive index modulation (n1ef, n2ef, and n3ef). The applicability conditions of such approximation are defined. The analytical dependencies of n1ef, n2ef, and n3ef on the amplitudes of the first, second and third harmonics of spatial frequency of the refraction index modulation amplitude n1, n2 and n3 are derived and the criteria of their applicability are established here. The resulting expressions for the diffraction efficiencies are given for readout at three Bragg angles. The results of analytical and numerical methods are compared. The obtained formulas are used for the calculation of n1, n2 and n3 of the holographic gratings generated in the photopolymer material.  相似文献   

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