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1.
Efficiency of the structure analysis of complex molecules in the gas phase by their optical rotation
V. A. Tolkachev 《Journal of Applied Spectroscopy》1998,65(6):883-890
It was shown in the dipole approximation of optical rotation that in the general case only in orientationally anisotropic
vapors is the rotational force dependent on the intramolecular orientation of both the electric and magnetic dipole moments.
Expressions relating the optical rotational force to the intramolecular orientation of these moments, the orientational distribution
in an anisotropic ensemble, and the configuration of a measurement have been obtained. Calculated dependences of the rotational
force on the intramolecular orientation of the magnetic moment at a fixed electric moment and “rotational force excitation
spectra” obtained for different types of rigid asymmetric top molecules and rotational contours are presented. It is proposed
to measure the intramolecular orientation of the electric and magnetic dipole moments with the use of the rotational force
normalized to that detected in the case of observation at a “magic” angle to the direction of the exciting light electric
vector.
Institute of Molecular and Atomic Physics of the Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 6, pp. 843–849, November–December, 1998. 相似文献
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3.
Antonino Marciano 《Czechoslovak Journal of Physics》2005,55(11):1479-1485
I summarize results recently obtained in collaboration with Amelino-Camelia, Bruno and Mandanici (preprint University of Rome
“La Sapienza”, August, 2005) that concern an analysis of the path of a massless particle in a q-de Sitter space-time and an approximation scheme suitable for the corresponding analysis in a quantum FRW Universe. On the
basis of some arguments in the quantum-gravity literature, the q deformation parameter is assumed to depend on both the Planck scale and the curvature, leading to results that are significantly
different from those of other studies of Planck-scale effects in cosmology, where the possibility of an interplay between
curvature and Planck scale was ignored.
Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005. 相似文献
4.
A method of constructing and analyzing exact solutions for inflationary cosmology models with a self-action scalar by introducing
an effective self-action potential is suggested. On the basis of exact solutions for complete and “shortened” equations obtained
in the “slow-descent” approximation, their comparative analysis is made. It is shown that the results obtained for approximate
models that are conventionally used for comparison with experimental data may differ greatly from those for exact models because
of the structural instability of models with inflation.
Ul'anovsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 14–20, January, 2000. 相似文献
5.
A. P. Bogatov 《Journal of Russian Laser Research》1994,15(5):417-453
The electromagnetic field inside a nonlinear active medium of a laser is considered as a system of counterpropagating waves.
Such an approach changes radically an earlier studied behavior of the lateral field instability due to self-deformaion (or
self-focusing). In our calculations we used an expression for a laser field in the form of two “strong” counterpropagating
waves whose complex amplitudes have weak perturbations. Amplitude perturbations of each of the “strong” waves can be presented
by two spatial harmonics corresponding to two weak perturbation waves with wave vectors making some tilted angle ±φ with the
cavity axis. Thus six waves would participate in the interaction: two counterpropagating strong waves and two pairs of weak
waves. Using this approach, we have developed a theory for the propagation of four “weak” perturbation waves in a nonlinear
amplifying medium in the presence of two counterpropagating “strong” waves. It is shown that perturbation waves with tilted
angle φ⋍0.5–1.2° inside the active region, and respecively, with the side lobes of the far-field pattern at ∼1.7–4°, have
the greatest growth increment. These perturbation waves produce lateral intensity modulation with period 10–30 μm for the
0.85 μm lasing wavelength. The appearance of such waves corresponds to the instability threshold of a homogeneous lateral
distribution of optical power in a diode laser.
The present theory makes it possible to investigate the stability of the homogeneous lateral optical intensity distribution
in a diode laser of any design. This allows one to choose a suitable design of a laser with a homogeneous lateral distribution
at high radiation power.
Translated from Preprint No. 43 (1992) of the Lebedev Physics Institute, Russian Academy of Sciences. 相似文献
6.
Yu. Kh. Vekilov I. A. Gordeev É. I. Isaev 《Journal of Experimental and Theoretical Physics》1999,89(5):995-999
The electronic spectrum and wave functions of a new quasicrystal structure—a two-dimensional Fibonacci lattice—are investigated
in the tight-binding approximation using the method of the level statistics. This is a self-similar structure consisting of
three elementary structural units. The “central” and “nodal” decoration of this structure are examined. It is shown that the
electronic energy spectrum of a two-dimensional Fibonacci lattice contains a singular part, but in contrast to a one-dimensional
Fibonacci lattice the spectrum does not contain a hierarchical gap structure. The measure of allowed states (Lebesgue measure)
of the spectrum is different from zero, and for “central” decoration it is close to 1. The character of the localization of
the wave functions is investigated, and it is found that the wave functions are “critical.”
Zh. éksp. Teor. Fiz. 116, 1834–1842 (November 1999) 相似文献
7.
8.
I. Ya. Erukhimovich A. V. Ermoshkin 《Journal of Experimental and Theoretical Physics》1999,88(3):538-544
A systematic “mean-field” treatment of the thermodynamic equilibrium formation of an infinite cluster of bonds in a system
of identical monomers capable of forming from n=0 to n>2 reversible chemical bonds with one another is proposed within the Cayley-tree approximation. For this purpose the difference
between the symmetry of the monomers appearing in “point-to-point” and closed bond paths, respectively, is taken into account
on the basis of an analysis of the structure of the infinite cluster. Minimization with respect to the distribution of such
monomers yields a nontrivial solution corresponding to a lower free energy than the classical solution, which does not allow
for the symmetry difference indicated. In addition, it is shown that the classical solution corresponds to the free-energy
maximum when the infinite cluster is formed and that the formation of the infinite cluster is a first-order phase transition.
The possible form of the phase diagrams of the systems considered is analyzed.
Zh. éksp. Teor. Fiz. 115, 979–990 (March 1999) 相似文献
9.
The characteristic features of experimental and theoretical investigations of the pass band in channels having discrete mutually
screening inhomogeneities are analyzed. A comparison is made of methods and methodologies for measuring the delay spectra
and the angular energy spectra of a multibeam field at a point of observation in such channels and in channels having continuously
distributed “transparent” inhomogeneities. It is shown that when estimating the pass band in the former, the delay spectrum
must be analyzed in a moving system of coordinates whose origin is coincident with the time of arrival of the first “beam.”
A corresponding theoretical analysis is performed for the case when the “beam” arrival times form a nonsteady-state Poisson
stream.
State University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 95–101, June, 1996. 相似文献
10.
E. Gotsman E. Levin U. Maor E. Naftali 《The European Physical Journal C - Particles and Fields》2000,14(3):511-523
We extend our previous treatment of the p cross section based on Gribov's hypothesis to the case of photon–photon scattering. With the aid of two parameters, determined
from the experimental data, we separate the interactions into two categories corresponding to short (“soft”) and long (“hard”)
distance processes. The photon–photon cross section thus receives contributions from three sectors, soft–soft, hard–hard and
hard–soft. The additive quark model is used to describe the soft–soft sector, pQCD the hard–hard sector, while the hard–soft
sector is determined by relating it to the system. We calculate and display the behaviour of the total photon–photon cross section and its various components and polarizations
for different values of energy and virtuality of the two photons, and discuss the significance of our results.
Received: 12 January 2000 / Published online: 6 April 2000 相似文献
11.
A. P. Gavrilyuk I. V. Krasnov Yu. G. Trapeznikov N. Ya. Shaparev 《Russian Physics Journal》1998,41(6):511-516
A model is considered for the interaction with plasma of an “optical membrane” formed by bichromatic intersecting laser beams.
This model is used to describe a number of effects resulting from the mechanical action of light on resonant ions in the plasma.
Krasnoyarsk Computing Center, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh
Zavedenii, Fizika, No. 6, pp. 9–14, June, 1998. 相似文献
12.
E. Z. Kuchinskii N. A. Kuleeva I. A. Nekrasov M. V. Sadovskii 《Journal of Experimental and Theoretical Physics》2010,110(2):325-335
The density of states, the dynamic (optical) conductivity, and the phase diagram of the paramagnetic two-dimensional Anderson-Hubbard
model with strong correlations and disorder are analyzed within the generalized dynamical mean field theory (DMFT + Σ approximation).
Strong correlations are accounted by the DMFT, while disorder is taken into account via the appropriate generalization of
the self-consistent theory of localization. We consider the two-dimensional system with the rectangular “bare” density of
states (DOS). The DMFT effective single-impurity problem is solved by numerical renormalization group (NRG). The “correlated
metal,” Mott insulator, and correlated Anderson insulator phases are identified from the evolution of the density of states,
optical conductivity, and localization length, demonstrating both Mott-Hubbard and Anderson metal-insulator transitions in
two-dimensional systems of finite size, allowing us to construct the complete zero-temperature phase diagram of the paramagnetic
Anderson-Hubbard model. The localization length in our approximation is practically independent of the strength of Hubbard
correlations. But the divergence of the localization length in a finite-size two-dimensional system at small disorder signifies
the existence of an effective Anderson transition. 相似文献
13.
A. S. Shalin 《Journal of Applied Spectroscopy》2006,73(5):719-726
The integrodifferential equation method is used to study the spectrum of a nanoparticle colloid for the example of interaction
of three arbitrarily arranged dielectric particles made up of nonresonant atoms (the eigenfrequency of the transition is far
from the emission frequency) with incorporated barium atoms in an external optical radiation field. The effect on the light-scattering
properties of a nanosphere in the ensemble of its distant “neighbors” is studied; an additional peak associated with them
is observed as a frequency close to the resonance for an isolated nanosphere, which under certain conditions has higher intensity
than the main peak corresponding to optical near-field resonance in a two-particle system. The dependence of the spectrum
of the nanosized system on the geometric structure is studied, and it is shown that very precise tuning of the resonance frequency
is possible by varying the angular distribution of the particles.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 641–646, September–October, 2006. 相似文献
14.
The character of the localization of the wave functions of an icosahedral quasicrystal is investigated in the tight-binding
approximation. It is found that the wave functions exhibit “critical behavior”: they are neither localized, as in the case
of Anderson localization, nor delocalized, as in the case of Bloch states.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 8, 559–563 (25 October 1996) 相似文献
15.
T. V. Panchenko 《Physics of the Solid State》1998,40(6):938-940
The spectral distribution of the uv-induced photoconductivity intensity and relaxation in Bi12SiO20 and Bi12GeO20 crystals both undoped and doped with Al, Ga, Cr, Cu, Mn, and V is investigated in the optical range 0.5–3.5 eV in the temperature
ranges 85–95 K and 285–295 K. It is shown that in the short-wavelength region 2.2–3.5 eV it is controlled by multicenter recombination
in which both “fast” and “slow” recombination participate.
Fiz. Tverd. Tela (St. Petersburg) 40, 1027–1029 (June 1998) 相似文献
16.
V. L. Komolov 《Technical Physics》1997,42(5):499-503
An investigation is made of the conditions for the nucleation of optical breakdown in transparent material when recombination-stimulated
defect-formation reactions occur in it. It is shown that a positive feedback between the conduction electron concentration
and point defects activates defect formation even if the medium is not heated. Under real conditions, where heating of the
medium by the light is important, lowering of the activation barrier by thermal defect generation aided by conduction electrons
results in optical breakdown of the medium at light intensities much lower than predicted in the classical “semiconductor”
or “thermochemical” models of thermal breakdown. The analysis confirms that optical breakdown of transparent condensed media
is due to electron-aided defect formation reactions over a broad range of illumination conditions.
Zh. Tekh. Fiz. 67, 48–53 (May 1997) 相似文献
17.
A. G. Zhdanov A. K. Zvezdin A. P. Pyatakov T. B. Kosykh D. Viehland 《Physics of the Solid State》2006,48(1):88-95
The specific features of the “incommensurate-commensurate” phase transitions induced by a magnetic field in multiferroics
(materials with coexisting magnetic and electric ordering) are considered. These materials are ferroelectromagnets, for example,
bismuth ferrite BiFeO3 and BiFeO3-based compounds, which have spatially modulated spin structures. It is shown that the interaction between the electric and
magnetic subsystems of the multiferroic material can lead to an electric-field-induced shift of the critical magnetic field
corresponding to the transition from a spatially modulated state to a homogeneous antiferromagnetic state. According to the
theoretical estimates obtained for material parameters characteristic of the bismuth ferrite, this shift is of the order of
0.5 T in an electric field of 50 kV/cm. The phase diagrams are constructed in the “electric field-magnetic field” coordinates.
The results of calculations performed in the harmonic incommensurate structure approximation are compared with the exact soliton
solution. 相似文献
18.
We apply the time-dependent local density approximation to the small carbon clusters. The carbon clusters of chain and ring
shapes are found to show strong π-electron transitions. An interpretation is given for them as the one-dimensional plasmon
excitation.
Presented by K. Yabana at the International Conference on “Atomic Nuclei and Metallic Clusters”, Prague, September 1–5, 1997. 相似文献
19.
The total energy, the equilibrium lattice constant, and the bulk modulus of the fcc phase of iron have been calculated by
the full-potential LMTO method. The use of a generalized gradient approximation in the calculation of the electronic structure
and lattice properties of γ-Fe is discussed. Next, the transverse phonon frequency at the W point of the Brillouin zone of a fcc lattice is calculated by the “frozen-phonon” method in the harmonic approximation. A
local minimum has been found in the curve of the variation of the total energy of the system as a function of the amplitude
of the atomic displacements corresponding to the chosen normal mode. To take account of anharmonic effects, a pseudoharmonic
approximation is used and an effective potential that approximates the curve of the variation of the total energy of the system
and depends on the temperature via the correlation function of the mean-square displacement of atoms from their equilibrium
positions is constructed. The theoretical temperature dependence of the effective frequency of the phonon mode responsible
for the structural phase transition corresponds qualitatively to the experimentally observed dependence. A new interpretation
is given for the structural phase transition as a transition of the corresponding phonon mode from the excited to the ground
state.
Fiz. Tverd. Tela (St. Petersburg) 39, 171–175 (January 1997) 相似文献
20.
A. G. Isavnin 《Russian Physics Journal》2006,49(3):308-313
Theoretically, based on the approximation of discrete orientations, the effect of thermal stochastic resonance is considered
for a superparamagnetic particle with magnetic anisotropy of the “easy axis” type in view of an additional external permanent
magnetic field applied at an arbitrary angle relative to the easy magnetization axis. The dynamic susceptibility has been
calculated for a single-domain iron particle under the conditions of its modulation by a weak external radio-frequency field
at various absolute values and directions of the additional permanent magnetic field vector.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 67–71, March, 2006. 相似文献