Faculty of Physics
M.V.Lomonosov Moscow State University
Theoretical and mathematical physics

## Interaction between planar gravitational and electromagnetic waves in an external gravitational field

### V.I. Denisov, V.A. Eliseev

Moscow University Physics Bulletin 1987. 42. N 2. P. 1

The process of interaction between a gravitational field and an electromagnetic field in the presence of an external gravitational field is examined for two classes of metric theories of gravitation. The results of this examination are used to find the conditions of resonance interaction and to show the possibility of continuous amplification of a planar electromagnetic wave by a planar gravitational wave. Numerical estimates of the possibility of formulating an experiment are given.

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## Multidimensional combination of a model of electromagnetic and weak Weinberg-Salam interactions with gravitation: a fermion sector

### V.V. Kislov

Moscow University Physics Bulletin 1987. 42. N 2. P. 6

Geometrical combination of gravitation with electromagnetic and weak interactions is examined with consideration of the fermion sector within the Kaluza-Klein theories. The SU(2) by U(1) calibrating group is formed in a seven-dimension model, while the SU(1,1) by U (1) group is formed in a six-dimensional model. The results of such combination are discussed.

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## A method for building calibrationally invariant Lagrangians for arbitrary Lie groups

### A.P. Demichev, N.F. Nelipa

Moscow University Physics Bulletin 1987. 42. N 2. P. 11

A general method is proposed for building calibrationally invariant Lagrangians which is based on the use of the theory of layered spaces and groups of transformations. The method makes it possible to acquire Lagrangians both with precise and with spontaneously disrupted symmetries. The Lagrangian for a nonuniform calibrating group of three-dimensional Euclidean movements is constructed as an example.

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## Field theory classification and singular perturbations

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

Moscow University Physics Bulletin 1987. 42. N 2. P. 18

A sequential analogy is drawn between classes of perturbative theories of quantum fields (superrenormalized, renormalized, and unrenormalized) and the behavior of the matrix elements in Rayleigh-Schr$\stackrel{..}{o}$dinger progressions for an anharmonic oscillator with a perturbation of $\lambda|x|^{-\nu}$. Each class of fields has its own range of values or the parameter $\nu$ for the case of even solutions of the Schr$\stackrel{..}{o}$dinger equation. The proposed analogy is different from those previously examined in the literature.

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## Quantum corrections in the quasiclassical theory of synchrotron radiation

### I.M. Ternov, V. Bordovitsyn

Moscow University Physics Bulletin 1987. 42. N 2. P. 24

A simple quasiclassical deduction of all (known) quantum correction to the power of synchrotron radiation of an electron is proposed. The effects of recoil in this case are naturally separated from the radiation of the intrinsic magnetic moment right up to the second order of smallness in terms of $\hbar$. The physical sense of the quantum corrections to the power of the synchrotron radiation in this way becomes even clearer.

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## The perturbation theory in statistical thermodynamics and its generalization

### I.P. Bazarov, P.N. Nikolaev

Moscow University Physics Bulletin 1987. 42. N 2. P. 28

A generalization of the thermodynamic perturbation theory is acquired on the basis of consideration of the nature of the expansion for free energy at high densities.

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## Fermion oound states in a Kerr-Newman field with a magnetic charge

### D.V. Galtsov, A.A. Ershov

Moscow University Physics Bulletin 1987. 42. N 2. P. 33

Approximate solutions to Dirac's equation for the charged particles of 1/2 spin in a Kerr-Newman field are constructed. An expression is found for the energy of quasistationary states with consideration of the possibility of their decay as a result of tunneling into a black hole. The question about existence of zero modes is discussed.

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Atomic and nuclear physics

## The magnetic forces which act on a particle in an isochronous cyclotron

### L.A. Sarkisyan

Moscow University Physics Bulletin 1987. 42. N 2. P. 39

It is shown that besides the known magnetic Lorentz, Thomas, and Kerst forces which act on a particle in a magnetic field with spatial variation, there is also a nonlinear sign-changing azimuthal force $F_{\phi} = —\frac{e}{c} [V_rH_s]$ caused by the nonlinear radial component of velocity and the S-th harmonic of the vertical component of the magnetic field, in the zone of total resonance in terms of the free radial fluctuations of the $S=Q_r$ index in perturbated orbits. This force leads to a post-resonance reduction in the amplitude of the forced radial oscillations (damping beatings) with a rise in the frequency $Q_r$ with preservation of the beam emittance.

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## F- and D-couplings and lepton decays of baryons in a quark model with four flavors

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

Moscow University Physics Bulletin 1987. 42. N 2. P. 46

The association between the constants of an F- and D-coupling of a weak, axially vector baryon current in SU(4) and the matrix elements of a quark current in the facings between three-quark states is found. It is shown that the constants of the F- and D-couplings characterize the quark-biquark structure of the baryons of the 20-braid SU(4).

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## Calculating the fraction of metastable helium atoms which are formed in the $He^{1+} + Na \to He+Na^{1+}$ reaction

### N.F. Vorob'ev, E.A. Kral'kina

Moscow University Physics Bulletin 1987. 42. N 2. P. 51

The portion of metastable particles which are formed with neutralization of $He^{1+}(^1S)$ ions in Na vapors in a region of collision rates of $v$ from 0.3 to 10 atomic units (at. un.) is calculated. The role in the formation of the fraction of metastable helium atoms of the process of electron capture into highly excited states with subsequent transitions to the metastable levels is explained. A comparison with the available experimental data is performed.

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## Excitation of the resonance levels of $Sr^+$ and $Ba^+$ ions in a discharge in a hollow cathode

### A.M. Devyatov, V.Kh. Fazlaev

Moscow University Physics Bulletin 1987. 42. N 2. P. 57

The mechanism of excitation of resonance levels of strontium ions $5р^2Р_{3/2}$ and barium ions $6р^2Р_{3/2}$ in a discharge in a running-water-cooled hollow cathode with a helium filler is studied at $р=0.4\div 1.6$ mmHg and $i_р=100\div 400$ mA and with an argon filler at $р= 0.075\div 0.5$ mmHg and $i_p=50\div 200$ mA. It is established that in the investigated conditions the occupation of the resonance levels of the ions chiefly occurs due to collision between the electrons and the ions and atoms in the ground states and their depletion - primarily due to spontaneous transitions.

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## A numerical method for analyzing the intrinsic slowed waves of a dielectric waveguide

### E.F. Alekseenko

Moscow University Physics Bulletin 1987. 42. N 2. P. 62

The problem of analyzing intrinsic slowed waves of a dielectric waveguide (DW) using projection and indirect variational methods is reduced to the problem for the intrinsic values. An iterational algorithm is proposed for solving this problem. The results are cited of an analysis of DW of different shapes and different distribution of the dielectric permittivity within the cross section.

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Optics and spectroscopy

## Manifestation of universal intermolecular interactions in the spectrally luminescent and generation properties of coumarine 1

### N.V. Korol'kova, B.M. Uzhinov

Moscow University Physics Bulletin 1987. 42. N 2. P. 67

The effect of universal intermolecular interactions on the luminescence and laser generation of coumarine 1 is investigated in different solvents. It is shown that solutions of coumarine 1 in polar solvents, in which the orientational intermolecular relaxation leads to a disposition of the energy levels of the molecules of the dye, which is favorable for generation, and to a reduction in the threshold of generation as compared to the threshold in nonpolar solvents, have the greatest effectiveness of generation.

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Acoustics and molecular physics

## Interaction between serum albumin and water at different concentrations of hydrogen ions based on data from Rayleigh scattering

### G.P. Petrova, Yu.M. Petrusevich, I.I. Shirkova, O.P. Revokatov

Moscow University Physics Bulletin 1987. 42. N 2. P. 71

Diluted solutions of serum albumin in water are studied at different values of the total surface charge in protein using a Rayleigh light scattering method. It is shown that the effective electron polarizability, the second virial coefficient, the degree of depolarization, and the parameters of the tensor of polarizability of the macromolecules of the protein are a nonlinear function of the pH of the solution and have an extremum at the isoelectric point.

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Solid state physics

## The role of structural defects and admixtures in reconstructing a (100) silicon surface

### V.V. Burmistrov, E.M. Dubinina, S.S. Elovikov, V.P. Ivannikov

Moscow University Physics Bulletin 1987. 42. N 2. P. 76

The (100) facet of silicon is investigated using methods of diffraction of slow electrons and electron Auger spectroscopy. (2 by 1), p(2 by 2), and c(4 by 4) superstructures are noted as the surface admixtures are removed from the sample. The c(4 by 4) superstructure is shifted into a(4 by 1) superstructure with subsequent electron effects ($T=450^{\circ} С$, E = 3 keV, and $D = 5\cdot 10^{19}$ electrons/cm$^2$). A model of the mutual transition of the cited elementary cells with each other is constructed using a quantum-chemical approximation of valent bonds.

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## A theory of formation of energy spectra of coherent Compton scattering

### V.A. Bushuev, A.O. Ait

Moscow University Physics Bulletin 1987. 42. N 2. P. 83

Coherent phenomena during Compton scattering (CS) of X-rays in ideal crystals are theoretically investigated. The problem about dynamic, two-wave Laue diffraction of Compton radiation in absorbing crystals of random thickness is solved in the general form. It is shown that the coherent Compton effect is a sensitive method for studying the nondiagonal elements of the electron density matrix in a pulsed space, especially with asymmetrical diffraction.

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Theoretical and mathematical physics

## A second order current and nonconservation of C-parity

### M.N. Dubinin

Moscow University Physics Bulletin 1987. 42. N 2. P. 90

The widths of $\tau \to \pi \eta \nu$ and $\eta \to \pi e^+e^-$ decays, in which a second order $\pi \eta$-current participates, are calculated. It is proposed that the charged and neutral $\pi \eta$-currents are components of a single isovector. The upward experimental limitation on the width of the electromagnetic decay $\Gamma (\eta \to \pi e^+e^-)/\Gamma_{tot}<4,5\cdot 10^{-5}$ which disrupts the C-parity makes it possible to acquire an estimate of $\Gamma (\tau \to \pi \eta \nu)/\Gamma_{tot}<5,3\cdot10^{-5}$ for the decay of a $\tau$-lepton.

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Atomic and nuclear physics

## Complex nuclei in primary cosmic rays as superhigh energy $\gamma$-quanta sources

### V.V. Balashov, V.L. Korotkikh, I.V. Moskalenko

Moscow University Physics Bulletin 1987. 42. N 2. P. 93

The role of complex nuclei in the formation of rigid cosmic $\gamma$-radiation is investigated. The calculated energy spectra of the $\gamma$-rays in a range of $10^8\div 10^{16}$ eV provides the basic characteristics of the experimental data which relate to the discrete Cygnus X-3 source.

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### A.V. Andreev

Moscow University Physics Bulletin 1987. 42. N 2. P. 97

A model is proposed of superradiation in a resonator in a mode of pulse self-extraction which is achieved by using slipping reflection from one of the facets of the resonator. The possibility of a substantial increase in intensity and a reduction in the pulse duration in such an arrangement is shown.

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Optics and spectroscopy

## Nonlinear gyrotropy in silver thiogallate

### V.A. Grabovskii, N.I. Zheludev

Moscow University Physics Bulletin 1987. 42. N 2. P. 101

Nonlinear absorption ($K_2 \sim З\cdot 10^{-3}$ Mw$^{-1}\cdot$cm) and nonlinear optical activity ($С\sim 3\cdot 10^{-3}$ deg$\cdot$Mw$^{-1}\cdot$cm) are measured in $AgGaS_2$ at a wavelength of 0.532 μm.

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## Investigation of the lifetime of the upper laser level of Ar II $4р^2D_{5/2}$ based on the spontaneous emission in a coupled transition

### L.E. Grin, O.S. Zaroslova, S.S. Kartaleva, V.V. Lebedeva, A.I. Odintsov

Moscow University Physics Bulletin 1987. 42. N 2. P. 105

The change in the lifetime of the upper laser level $4р^2D_{5/2}$ in the plasma of an argon laser is investigated using the spontaneous emission in a transition coupled with the laser transition. With a rise in the concentration of electrons from $10^{13}$ to $10^{14}$ cm$^{-3}$ the lifetime of the level is reduced from 10 to 4 nsec, which may be totally associated with the rise in the number of electron collisions.

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Acoustics and molecular physics

## Processes of dynamic reorientation of a nematic liquid crystal

### Yu.V. Vasil'ev, E.F. Kuritsyna

Moscow University Physics Bulletin 1987. 42. N 2. P. 109

An experimental investigation is performed of the transition processes in a plane-parallel optical cell based on a nematic liquid crystal with a staged change in the magnitude of the magnetic field which creates deformations such as pure twisting of the director.

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## Speeding up calculation when solving inverse scattering problems using iterational methods

Moscow University Physics Bulletin 1987. 42. N 2. P. 112

Certain simplified variants of a previously proposed iterational algorithm for solving inverse scattering problems with consideration of rescatterings of a wave which probes a heterogeneity are examined. The errors in restoration of the function which describes this particular heterogeneity are estimated. They form due to the introduced simplification. A solution method is proposed which makes it possible to greatly accelerate restoration of the disperser. The effectiveness of the method is illustrated by some results from a model experiment.

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Solid state physics

## The Staebler-Wronski effect in a-Si:H films implanted with boron and phosphorus ions

### I.A. Kurova, I.P. Akimchenko, K.B. Chitaya

Moscow University Physics Bulletin 1987. 42. N 2. P. 116

It is established in experiments in a-Si:H films implanted with boron and phosphorus ions that with total concentration of the implaned B and P ions $N_B$ and $N_Р$ of less than $5\cdot 10^{19}$ cm$^{-3}$ the Staebler-Wronski effect, a change in the dark conductivity and its energy of activation after illumination of the films by white light, is observed. At $N_P, N_B>5\cdot 10^{19}$ cm$^{-3}$ there is no such effect. The nature of the observed patterns is discussed.

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## Resonance phenomena with the effect of $CO_2$-laser radiation on a germanium surface

### A.V. Zoteev, V.F. Kiselev

Moscow University Physics Bulletin 1987. 42. N 2. P. 120

Mass spectrometry is used to investigate desorption of isolated molecules from the surface of germanium and oxidized germanium stimulated by infrared radiation from a $CO_2$-laser. A comparison with the process of thermodesorption is performed and proposals are advanced about the resonance effects in the mechanism of photodesorption.

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## Change in the nature of exchange interactions in Heusler alloys with a replacement of Co for Cu

### P.N. Stetsenko, V.V. Surikov, A.I. Laskin

Moscow University Physics Bulletin 1987. 42. N 2. P. 124

RCCI (the preasymptotic form) and Caroli-Blandin models are used for calculating the Fermi wave vector and the exchange integrals in $Cu_2MnAl$ and $Co_2MnAl$ alloys. The experimentally acquired values of the spin polarizations for the first and second coordinational spheres serve as the initial information. It is shown that the basic role in the $Cu_2MnAl$ alloy is played by a mechanism of d-resonance scattering, while it is played by sd-exchange in the $Co_2MnAl$ alloy.

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## Spectral characteristics of antiferromagnetic resonance of MnVG garnet

### M.V. Levanidov, V.I. Sokolov

Moscow University Physics Bulletin 1987. 42. N 2. P. 127

Antiferromagnetic resonance is detected in an $NaCa_2Mn_2V_3O_{12}$ crystal which contains octahedral $Mn^{2+}$ ions. It is established that there is an isotropic slot ($\Delta ^2$) in the antiferromagnetic resonance spectrum of the crystal, whose value is maximal at T $\sim$ 7K and is sharply reduced with a reduction in temperature. The results of measurements of the static magnetostriction of the same crystal justifies the hypothesis that $\Delta ^2$ is not related to the magnetoelastic interaction. The possible mechanism of the observed characteristics of the antiferromagnetic resonance in this crystal is discussed. This is interaction of the Jahn-Teller admixtures of the $Mn^{3+}$ ions in the crystal.

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