Beam instability in a relativistic plasma
Beam instability in a relativistic plasma
A.N. Matveev, P.A. Polyakov, M.A. Tasev
The question about wave excitation in a one-dimensional relativistic plasma by a low density electron beam with low thermal scattering of the particles is investigated. The increment of excitation of plasma waves is found for frequencies similar to a low-frequency intrinsic mode. The influence of thermal scatter of the beam electrons on the frequency of oscillations and the increment in instability of the excited wave is analyzed.
Show AbstractThe effect of electron-hole correlations on the luminescence of crystalline phosphor with traps
The effect of electron-hole correlations on the luminescence of crystalline phosphor with traps
A.N. Vasil'ev, V.V. Mikhailin, I.V. Ovchinnikova
A model of a crystalline phosphor with traps with two channels of electron-hole recombination (direct and through the luminescence center) is examined. The dependence of the quantum output of luminescence of one of the channels on the dispersion length of the electron and hole during the hot relaxation stage is established. The dependence of the quantum output of luminescence on the energy of the incident photons, the intensity of the incident light, and its temperature is constructed.
Show AbstractEvaluating the magnitude of nonuniform expansion of the fluorescence spectrum of rhodamine 6G in glycerin
Evaluating the magnitude of nonuniform expansion of the fluorescence spectrum of rhodamine 6G in glycerin
I.A. Struganova
The formation of an imbalanced distribution of fluorescing centers at frequencies of a 0-0 transition in a dipole solvent-dye system and the subsequent transformation of the imbalanced distribution into balanced over a time of $\tau_R$ is examined. The magnitudes of nonuniform expansion of the fluorescence spectrum and the time $\tau_R$ for a solution or rhodamine 6G in glycerin are estimated on the basis of the measured relations of the time for fading of the fluorescence of this solution.
Show AbstractLight scattering in polaritons in a biaxial crystal near the binormal
Light scattering in polaritons in a biaxial crystal near the binormal
T.V. Laptinskaya, A.N. Penin, M.V. Chekhova
The features of the frequency-angle spectrum of scattering in polaritons in a biaxial crystal, which form when the wave vector of the polariton is oriented near the binormal, are examined. When the scattering plane deviates from the plane containing the binormal the scattering branch is disintegrated along the wave vector; the corresponding distribution in intensity in this case may be explained by the change in the magnitude of the convolution of the quadratic susceptibility with unit vectors of polarization of three interacting waves with rotation of the unit vector of polariton polarization.
Show AbstractApplication of the Monte Carlo method for investigating energy migration in complex organic compounds
Application of the Monte Carlo method for investigating energy migration in complex organic compounds
A.A. Demidov
The Monte Carlo method is used to investigate exciton migration in complex organic compounds. The Monte Carlo method used in the work does not require a priori limitations on the parameters of the compounds and uses only the spatial structure of the compounds and the spectroscopic characteristics of the molecules which comprise them. The potential of the method is demonstrated in an example of phycobilicom - a composite part of the light collecting antenna of some photosynthesizing organisms.
Show AbstractCoherent phenomena in a "band-level" system in a fluctuating field
Coherent phenomena in a "band-level" system in a fluctuating field
V.Yu. Finkel'stein, V.A. Namiot
The role of radiation fluctuations in the suppression of periodic "surge-like" returns of a system to the ground state with excitation from it into a band of discrete levels is studied. It is shown that the suppression is determined by the ratio of the width of the radiation line to the width of the excitation region into the band. With slow frequency fluctuations the suppression may be weakened, while with resonance on the edge of the band and amplitude fluctuations it, on the contrary, rises sharply.
Show AbstractThe role of collective effects in the formation of V ultraviolet spectra of rare-earth ions in crystals
The role of collective effects in the formation of V ultraviolet spectra of rare-earth ions in crystals
L.I. Devyatkova, A.A. Druzhinin, O.N. Ivanova, V.V. Mikhailin, S.P. Chernov
The evolution of V ultraviolet spectra of $BaY_2F_8$ crystals as the yttrium ions are replaced by ions of rare-earth elements of the ytterbium subgroup is investigated. Even transitions into the paired d-states, which correspond to the rare-earth ions which are close neighbors in the Bravais lattic yttrium, take part in the formation of the spectrum at comparatively low concentrations of the substituting ions. At greater concentrations the nature of the spectrum is determined by the presence or absence of exciton-like f-d states which are split off from the conduction zone.
Show AbstractPhase transformations and differentiating material in the Earth's mantle
Phase transformations and differentiating material in the Earth's mantle
M.V. Avdulov
Separation of the Earth's mantle into mineralogical fractions at a temperature below the solidus point of the rock occurs with periodic changes in temperature under the effects of polymorphous transformations. Estimations of the influence of the Bjerknes forces and the force of radial pressure on the kinetics of the process are cited.
Show AbstractInteraction between a particle ensemble and planar wave field with variable parameters
Interaction between a particle ensemble and planar wave field with variable parameters
A.M. Khapaev, I.V. Ponomarev
A functional which describes the change in the energy of an electron ring as a function of an external field is constructed to analyze interaction between a particle ensemble and a planar wave field with variable parameters. One of the possible modes of its change is examined to the extremum.
Show AbstractIs the $\lambda x^{-2}$ barrier penetrable?
Is the $\lambda x^{-2}$ barrier penetrable?
V.B. Gostev, A.R. Frenkin
Physically preferable self-adjoint expansion of a Hamiltonian with a property of $s(s+ 1)х^{-2}, — 1/2 < s < 1/2$ is selected. It is used to indicate a method for continuation through point $x=0$ of solutions of the Schr$\stackrel{..}{o}$edinger equation with a potential with the same property. After this standard rules are used to find the unambiguous coefficient of passage T of the $\lambda x^{-2}$ barrier (pit). In light of the uniformity of the Hamiltonian this coefficient in the absence of the additive barrier $h\delta (x)$ is not a function of energy. The coefficient T for a Coulomb barrier (pit) is cited.
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