Faculty of Physics
M.V. Lomonosov Moscow State University

# Issue 6, 1987

Theoretical and mathematical physics

## Cosmology in the Einstein-Cartan theory. 1. Spin dynamics

### V.A. Korotkii, Yu.N. Obukhov

Moscow University Physics Bulletin 1987. 42. N 6. P. 1

A study is reported of spin dynamics for a Wayssenhoff liquid in a gravitational field. The following theorem is proved: the nontrivial spin of the Wayssenhoff liquid that satisfies the Frenkel condition is conserved if and only if the liquid moves without acceleration.

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## Rayleigh-Schroedinger coefficients for singular perturbations of the discrete spectrum

### V.B. Gostev, A.R. Frenkin

Moscow University Physics Bulletin 1987. 42. N 6. P. 7

It is shown that the level shift of the even states in the discrete spectrum, produced by the singular perturbation $\lambda |x|^{-\nu}$, can be described by the standard Rayleigh-Schroedinger formulas only for $0 < \nu < 3/2$.

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## Exact dynamic theories operating on a given background

### A.N. Petrov, A.D. Popova

Moscow University Physics Bulletin 1987. 42. N 6. P. 13

Exact dynamic theories induced by the subdivision of the variables in the original field theory into a background and a finite dynamic part are constructed. They exhibit a certain nonequivalence under different cases of the subidivied variables. Gauge invariance that follows from displacements in 4-space and dynamic theories in GTR are discussed.

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## Synchrotron neutrinos at ultrahigh energies

### A.V. Borisov, I.A. Kelekhsaeva

Moscow University Physics Bulletin 1987. 42. N 6. P. 20

The probability of emissioт of a pair of muon neutrinos by an electron moving in a constant magnetic field is determined within the framework of the standard theory of electroweak interactions. The dependence of this probability the electron energy and the external magnetic field is investigated.

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## Transformation from the Mittag-Leffler expansion to the expansion of the potential of an arbitrary body in the region of its analyticity

### N.A. Chuikova

Moscow University Physics Bulletin 1987. 42. N 6. P. 62

A transformation is found between the function 1/(1 - z) of a complex variable, defined a two-dimensional stellar region, to the reciprocal distance $1/\Delta$ that is a function of a real variable defined in three-dimensional space. Formulas relating the coefficients of the expansion of $1/\Delta$ in terms of spherical functions with the coefficients of the Mittag-Leffler expansion of the corresponding complex function 1/(l - z) are derived.

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Atomic and nuclear physics

## Intermediate-energy behavior of the helicity of massive Dirac neutrinos when they are scattered by nucleons and its astrophysical aspects

### B.K. Kerimov, A.M. Mourao, V.P. Tsvetkov

Moscow University Physics Bulletin 1987. 42. N 6. P. 24

The differential and total cross sections for the elastic scattering of massive Dirac neutrinos by nucleons have been evaluated at intermediate energies ($E_{\nu}\ll M_N$), taking into account the neutrino helicity before and after scattering. The behavior of the neutrino helicity under the conditions prevailing in a neutron star has been investigated.

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## Determination of the strength functions for giant multipole resonances in the semimicroscopic model of nuclear vibrations

### A.N. Gol'tsov, B.S. Ishkhanov, V.N. Orlin

Moscow University Physics Bulletin 1987. 42. N 6. P. 29

A method is described for calculating the strength functions for giant multipole resonances (GMR). The fragmentation of particle and hole excitations is taken into accountt as is the coupling of the GMR to the continuum. The method is used to calculate the photoabsorption cross section of the nucleus $^{12}C$.

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## Diffraction radiation produced during the excitation of cyclotron waves in a relativistic electron beam

### V.I. Kanavets, A.V. Fedorov, V.A. Cherepenin

Moscow University Physics Bulletin 1987. 42. N 6. P. 36

Diffraction radiation generated when fast and slow cyclotron waves are excited in a relativistic electron beam is examined theoretically. The focusing magnetic field $H_0$ is shown to play a fundamental role in this process and that it can be used to control the amplitudes of radiated harmonics in multimode diffraction generators.

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## Richardson plot for the (110) plane of a tungsten single crystal

### E.E. Azizov, V.A. Mashtakova, B.B. Shishkin

Moscow University Physics Bulletin 1987. 42. N 6. P. 42

Thermionic emission from the (110) plane of a tungsten single crystal was investigated and it was shown that there is a threshold temperature at which the emission parameters determined from the Richardson plot undergo an increase.

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Acoustics and molecular physics

## Diffraction of acoustic waves by a half-plane parallel to the free surface of a stratified compressible liquid

### R.R. Gabdullin, A.K. Shatov

Moscow University Physics Bulletin 1987. 42. N 6. P. 51

An analysis is given of the diffraction of acoustic waves by a rigid-half plane parallel to the free surface of a stratified compressible liquid. The solution is given in the form of an integral whose asymptotic behavior in the far-field zone is examined.

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## Second viscosity in a vibrationally nonequilibrium gas

### A.I. Osipov, A.V. Uvarov

Moscow University Physics Bulletin 1987. 42. N 6. P. 57

The relevance of the concept of second viscosity in hydrodynamic processes in a nonequilibrium gas is discussed with allowance for the presence of a pump and heat transfer. It is shown that the second viscosity coefficient may be negative under certain particular conditions but this does not affect the overall positive sign of the total production of entropy in the system.

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Optics and spectroscopy

## Enhancement of the luminescence of rhodamine 6G in a colloidal solution of silver

### B.D. Ryzhikov, R.E. Shikhlinskaya

Moscow University Physics Bulletin 1987. 42. N 6. P. 46

An enhancement of the luminescence and absorption of rhodamine 6G in a colloidal water solution of silver has been found. The enhancement coefficient has been investigated as a function of the optical properties of the colloidal solution, the exciting wavelength, and the thickness of the solution. Electronic resonances in the metal particles are discussed as a possible mechanism of enhancement.

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Astronomy

## Secular and long-term perturbations of the inner orbit of the multiple system $\xi U.Ma.$

### A.A. Orlov, N.A. Solovaya

Moscow University Physics Bulletin 1987. 42. N 6. P. 68

Perturbations of the inner orbit of the multiple stellar system $\xi U.Ma.$ are calculated usirig formulas derived in previously published papers. Secular changes in the elements $e_1$, $\Omega_1$ and $I_1$ are reported. The results show that the perturbations of the inner orbit are substantial and must be taken into account.

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Solid state physics

## Simulation of back and transmission sputtering of atoms under the ion bombardment of single-crystal and quasiamorphous two-component targets

### V.N. Samoilov, V.A. El'tekov, B. Fritzsch, N.G. Anan'eva

Moscow University Physics Bulletin 1987. 42. N 6. P. 72

A dynamic model of a block of atoms is used to compare the sputtering parameters of two-component single-crystal and amorphous targets. The simulation is performed for the case of ion bombardment of the (0001) plane of VSi$_2$ single crystal and a corresponding quasiamorphous target with Ne$^+$ ions with energies of 10 keV, incident normally.

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Atomic and nuclear physics

## Mass formulas for charmed baryons

### L. Gelmi, V.S. Zamiralov, S.N. Lepshokov

Moscow University Physics Bulletin 1987. 42. N 6. P. 77

The hypothesis of quark-biquark structure of ordinary and charmed baryons can be used to express unambiguously the constants in the mass formulas of the quark models with flavors u, d, s, c in terms of the F- and D-coupling constants in the baryonic symmetry SU(4). The result is generalized to SU(n) symmetry.

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## Local cathodoluminescence of graded-gap semiconductors

### V.I. Petrov, E.E. Skvortsova, A.V. Shabalin

Moscow University Physics Bulletin 1987. 42. N 6. P. 81

An expression is obtained for the spatial distribution of nonequilibrium carriers in a graded-gap semiconductor excited by a focused electron probe. Comparison between calculated and experimental spectra is used to estimate the diffusion length and the reduced surface recombination rate.

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Solid state physics

## Quasisynchronous excitation of plane acoustic waves of finite amplitude by a moving $\delta$-localized source

### V.E. Gusev

Moscow University Physics Bulletin 1987. 42. N 6. P. 84

An analytic description is obtained for the generation of nonlinear sound by moving $\delta$-localized sources.

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