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1.
Ivanovski V Petrusevski VM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(7):1601-1607
A complete investigation of the phonon mixing in the nu3(SO4(2-)) frequency region was made, under experimental geometry where the reflecting crystal plane and the plane of incidence contain two principal dielectric axes. It was shown that although it is monoclinic, in the frequency region under inspection, gypsum could be treated as an orthorhombic crystal. More sophisticated model dielectric functions were introduced for the explanation of the Evans holes in the reflectance spectra. Using the model dielectric function, an appearance of the shoulder at the higher frequency part of the reflectance band was explained in terms of longitudinal and quasilongitudinal phonons. A possibility for Evans type interaction was encountered between the nu3(SO4(2-)) Au symmetry type mode and probably some of the combination modes. 相似文献
2.
N. I. Medvedeva I. R. Shein O. Yu. Gutina A. L. Ivanovskiĭ 《Physics of the Solid State》2007,49(12):2298-2302
The structural, electronic, and magnetic properties and the enthalpy of formation of iron borocementites Fe3C1?x Bx (x= 0, 0.25, 0.50, 0.75, 1.00) are analyzed using ab initio calculations in the framework of the electron density functional theory. It is found that the unit cell parameter a of the orthorhombic lattice increases linearly and the parameters b and c decrease as the boron concentration increases. The density of states at the Fermi level changes only slightly, and the main variations in the band structure occur in the region of the bottom of the valence bands. The magnetic moment of the iron atoms and the total magnetization and stability of the Fe3C1?x Bx phases increase linearly with an increase in the boron concentration. 相似文献
3.
D.?KrstovskaEmail author G.?Ivanovski O.?Galbova 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,45(3):325-330
The propagation of a monochromatic longitudinal acoustic wave along the low conductivity axis of a
thin quasi-two-dimensional conductive film, in the absence of an external magnetic field, is studied theoretically.
It is shown that under certain conditions the formation of both a standing ordinary wave (OAW) and an anomalous acoustic
wave (AAW) is possible.
The frequency dependence of the amplitudes of both waves is derived.
For certain values of the characteristic parameters, the AAW in the film may be dominant.
From the resonance conditions for the formation of standing OAW and AAW waves (especially the AAW), it is possible to obtain
information about the electronic structure of the quasi-two-dimensional conductors,
e.g. the corrugation parameter η or the relaxation properties of the charge carriers. 相似文献
4.
M. Mijatović G. Ivanovski B. Veljanoski K. Trenčevski 《Zeitschrift für Physik A Hadrons and Nuclei》1993,345(1):65-77
We have investigated the scattering and bound states of a nonrelativistic spin-1/2 particle in the system ofN magnetic barriers (or magnetic wells) andN magnetic delta functions. We have studied three types of problems: tunnelling with spin, band structure and change of polarization during transmission and reflection. 相似文献
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6.
This paper reports on the results of the ab initio FLAPW-GGA band structure calculations for two new layered phases SrRu2As2 and BaRu2As2, which are isostructural and isoelectronic to the known tetragonal (Ca,Sr,Ba)Fe2As2 basis phases of the FeAs superconductor family. The energy bands, densities of states, topology of the Fermi surface, low-temperature
electron specific heats, and molar Pauli paramagnetic susceptibilities of SrRu2As2 and BaRu2As2 are determined for the first time and discussed in comparison with those for BaFe2As2 and BaRh2As2. 相似文献
7.
The atomic structures, energies of formation, electronic structures, and thermal stabilities (in the temperature range T = 0–3000 K) of novel hybrid boron-nitrogen nanostructures (so-called nanopeapods B12N12@BN-NT) are simulated using the self-consistent density functional tight-binding (DFTB) method. The B12N12@BN-NT nanopeapods are regular linear ensembles of B12N12 boron-nitrogen fullerenes encapsulated in boron-nitrogen nanotubes (BN-NT), such as the (14, 0) nonchiral zigzag BN nanotubes, the (8, 8) nonchiral armchair BN nanotubes, and the (12, 4) chiral BN nanotubes. 相似文献
8.
A perturbation theory model that describes splitting of the spectra in highly symmetrical molecular species in electrostatic field is proposed. An anahrmonic model of a two-dimensional oscillator having Kratzer potential energy functionis used to model the molecular species and to represent the unperturbed system. A selection rule for the radial quantum number of the oscillator is derived. The eigenfunctions of a two-dimensional anharmonic oscillator in cylindrical coordinates are used for the matrix elements representing the probability for energy transitions in dipole approximation to be calculated. Several forms of perturbation operators are proposed to model the interactionbetween the polyatomic molecular species and an electrostatic field. It is found that the degeneracy is removed in the presence of the electric field and spectral splitting occurs. Anharmonic approximation for the unperturbed system is more accurate and reliable representation of a real polyatomic molecular species. 相似文献
9.
Ivanovski V Petrusevski VM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(9):2057-2063
An investigation of the IR polarized reflectance spectra of the orthorhombic K2SO4, KHSO4 and monoclinic CaSO4 x 2H2O, K2Ni(SO4)2 x 6H2O, (NH4)2Ni(SO4)2 x 6H2O was performed in order to explain the appearance of particular intersection points in their spectra. The analogy in the origin of the appearance of intersection points and the well-known isosbestic points in UV-vis and IR spectra was discussed. The reason for such an appearance was identified in the way that the individual reflectances (for radiation polarized along principal dielectric axes) sum up to give the reflectance under arbitrary polarization. This summation may also produce supplementary bands in the reflectance spectra, not predicted by the group theory. It was shown that relatively large LO-TO splitting is needed for the supplementary band(s) to appear, but also the overlapping region must be taken into account. 相似文献
10.
The morphology, energy stability, and thermal behavior of a family of MgO tubular nanocrystallites are investigated within the framework of the pair potential model. It is found that an increase in the number of layers forming walls of hollow MgO nanocrystallites of prismatic morphology results in an abrupt enhancement of their stability. It is concluded that the properties of these nanostructures should be stable over a wide range of crystallite sizes. 相似文献