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

## Electromagnetic radiation absorption and reaction rates in partially ionized plasma

### M.A. Drofa, L.S. Kuzmenkov, S.G. Maximov

Moscow University Physics Bulletin 1997. 52. N 2. P. 1

The balance equations of particle number and momentum for systems with ionization and recombination of particles have been obtained. In the limit of low temperatures, for a hydrogen-like four-component system in an ionizing radiation field the dispersion relations have been found, which prove the existence of electromagnetic radiation absorption regions whose boundaries depend on the degree of ionization and elementary processes rates. Experimental determination of these boundaries may provide data on elementary processes rates.

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Atomic and nuclear physics

## A model for describing cross sections of photoneutron reactions on heavy weakly deformed nuclei

### S.S. Borodina, B.S. Ishkhanov, V.I. Mokeev

Moscow University Physics Bulletin 1997. 52. N 2. P. 7

A method for describing cross sections of photo-neutron reactions on nuclei with mass numbers A > 80 has been developed. This method can be employed for solving problems of radioactive isotopes transmutation, as well as for numerous applied and fundamental studies, where the description of photoneutron cross sections is needed and no experimental data are available.

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Optics and spectroscopy

## Slow induction of fluorescence of bean leaves on their treatment with $КН_{2} РО_{4}$ solutions

### S.A. Dovyd'kov, V.A. Karavaev

Moscow University Physics Bulletin 1997. 52. N 2. P. 13

The effect of $КН_2Р0_4$ solutions on the induction changes in bean leaf fluorescence has been studied using different methods of plant treatment: via the root system or by introducing the solutions into the leaf vein. It has been shown that irrespective of the method of treatment, the maximal changes in fluorescence induction occurred at a $10^{-5}- 10^{-4} М$ concentration of the $КН_2Р0_4$ solution. The dependence of the parameters of slow induction of fluorescence on time after phosphate treatment of the leaf has been studied. A positive correlation between relative fluorescence quenching in the course of slow induction and the stationary rate of photosynthesis has been established.

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## About possible origin of continual emission bands recorded in spectra of a plasma containing heavy inert gases doped with sulfur trioxide

### I.S. Lakoba$^1$, S.P. Chernov$^2$, P.B. Essel'bakh$^2$

Moscow University Physics Bulletin 1997. 52. N 2. P. 18

Spectral continua with peaks of intensity near 350 and 248 nm, found in the radiation of plasma mixtures containing $SO_3 +Хе$ and $SO_3 + Kr$, respectively, are presumably attributed to transitions of exciplexes $XeSO_4^*$ and $KrSO_4^*$ from the lower Coulomb state to the ground state. Proceeding from this assumption, the electron affinity energy of the radical $SO_4$ is estimated to be $ЕА_{SO_4}\approx 4,5$ eV.

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Solid state physics

## Temperature and concentration dependences of $Gd_{1-x}Zr_xCo_2$ exchange and zone magnetostriction

### S.A. Nikitin, A.K. Kupriyanov, Z.S. Umhaeva

Moscow University Physics Bulletin 1997. 52. N 2. P. 23

The results of an investigation into the magnetostriction properties of $Gd_{1-x}Zr_xCo_2$ intermetallic compounds as a function of zirconium concentration have been presented for magnetic fields strength of 13 kOe and in the temperature range from 77 to 360 K. Volume magnetostriction is shown to comprise the exchange and zone contributions. The temperature and concentration dependences of these contributions have been found. It has been shown that the obtained dependences of magnetostriction can be justified by significant changes in the d-zone structure.

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## The role of protons in charging the semiconductor surface

### V.B. Zaitsev, V.F. Kiselev, D.I. Ol'shanskii, G.S. Plotnikov

Moscow University Physics Bulletin 1997. 52. N 2. P. 29

Recharging exchange of surface states in the structures of $Ge-GeO_2$-adsorbed molecules of weak organic photoacids (naphthols) - was studied. As a result of adsorption or lighting, naphthol molecules can give away their protons and become anion-radicals. Naphthols manifested a strong influence on the parameters of all groups of slow surface states.

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## Photoinduced effects in $\alpha Si:H$ films at elevated temperatures

### I.A. Kurova, N.N. Ormont, D.V. Senashenko

Moscow University Physics Bulletin 1997. 52. N 2. P. 35

The kinetics of dark conduction $(\sigma_d)$ in high-resistance $\alpha Si:H$ films during and after illumination at elevated temperatures (T > 120°C ) has been studied. It has been established that the $\sigma_d(t)$ value changes nonmonotonically: during illumination, it first decreases and then increases; after illumination, it first increases to a value larger than the equilibrium one and then slowly decreases to the equilibrium value. It has been shown that the time dependences of $\sigma_d(t)$ relaxation can be described by the sum of two extended exponents with different parameters $\tau$ and $\beta$. The nature of nonmonotone changes in $\sigma_d(t)$ is discussed.

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## Ascending diffusion in hydrogen-saturated palladium-samarium alloys

### G.P. Revkevich, M.K. Mitkova, A.A. Katsnel'son

Moscow University Physics Bulletin 1997. 52. N 2. P. 39

Changes in the X-ray diffraction for a Pd-4.5 at.% Sm hydrogen-saturated alloy have been studied. Ascending diffusion in samarium atoms has been observed, which is caused by a chemical affinity stronger for hydrogen than for palladium.

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Geophysics

## Interaction of wind waves with the atmosphere and the field of surface heterogeneities in the coastal zone

### E.P. Anisimova, V.L. Lebedev, K.V. Pokazeev, A.A. Speranskaya

Moscow University Physics Bulletin 1997. 52. N 2. P. 44

The influence of some physico-chemical heterogeneities of the sea surface (the presence of surfactants, drift currents, and stratification of the air layer adjacent to water) on the characteristics of the wind-wave interaction has been studied.

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## Estimation of the coefficient of turbulent diffusion for a solid impurity in a suspension flow

### Yu.G. Pyrkin, I.B. Romanova, M.A. Silayev

Moscow University Physics Bulletin 1997. 52. N 2. P. 50

An expression was derived for the coefficient of turbulent diffusion of solid particles (particulates) as a function of the parameters of a suspension flow. The variation of this coefficient with the flow depth was calculated on the basis of experimental data.

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## Internal gravitational and magnetic fields in the analysis of polar oscillations of the Earth's inner core

### N.A. Chuikova, S.A. Kazaryan, S.L. Pasynok

Moscow University Physics Bulletin 1997. 52. N 2. P. 53

The problem of polar oscillations of the Earth's inner core was solved according to the Slichter-Busse procedure with account taken of the forces induced by the attraction of the asymmetric cover of the Earth and by the presence of a magnetic moment in the inner core. The internal gravitational and magnetic potentials were simulated in the form of the potentials of a single layer located on the spherical surface of the outer core. Two models of the gravitational potential were considered. The first was constructed on the basis of the external gravitational field of the Earth and the second model was based on seismic data. It was found that the choice of the model has no appreciable effect on the frequency of possible oscillations of the inner core and strongly affects the displacement of the Earth's core.

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## Polarization effects and the baroelectric field

### V.I. Grigor'ev, V.S. Rostovskii

Moscow University Physics Bulletin 1997. 52. N 2. P. 60

The redistribution of charges inside the atomic cells of a substance under the action of the baroelectric field is studied with account taken of the gravitational and electrical contraction of celestial bodies.

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Astronomy

## Ionization of hydrogen in optically dense atmospheric layers of cool stars

### E.A. Bruevich, N.A. Katysheva

Moscow University Physics Bulletin 1997. 52. N 2. P. 66

The gas ionization parameter $(N_e) / (N_e+n_1)$ was calculated for various gas densities and temperatures by two probabilistic methods for solving steady-state equations. The results produced by these methods were compared with those obtained by other authors. It is shown that the ionization parameter of a gas depends rather strongly on its optical thickness, density and temperature.

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Theoretical and mathematical physics

## Finslerian consequences of special relativistic approach versus Mansouri-Sexl test theory

### G.S. Asanov

Moscow University Physics Bulletin 1997. 52. N 2. P. 73

Two new theorems are given that define invariant properties of Finslerian kinematic transformations and of Finslerian metric tensor.

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## Calculation of processes in inhomogeneous plates under local thermal actions

### G.N. Medvedev and B.I. Morgunov

Moscow University Physics Bulletin 1997. 52. N 2. P. 76

Thermal and mechanical processes arising under local thermal actions on plates made of a homogeneous or an inhomogeneous material are considered. If the material is inhomogeneous, its characteristics vary considerably with the coordinate corresponding to the thickness of the plate. External thermal perturbations are concentrated in a small region and have a significant value. Temperature and displacement vector are determined with the use of an asymptotic procedure.

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## Topological self-action in the space $M_2\times V_2$

### Yu.V. Grats, A.B. Lavrent'ev

Moscow University Physics Bulletin 1997. 52. N 2. P. 78

The effect of topological self-action experienced by a stationary distribution of currents and charges on the space $M_2\times V_2$ ($М_2$ is the two-dimensional Minkowski space and $V_2$ is a two-dimensional Riemann surface) is examined. The case of a locally plane multiconic space is considered.

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## Higgs boson associative production by leptons in the field of an electromagnetic wave

### K.V. Zhukovsky, P.A. Eminov

Moscow University Physics Bulletin 1997. 52. N 2. P. 81

The probability of associative production of Higgs and Z-bosons by a charged lepton in the field of a plane electromagnetic wave of arbitrary intensity has been computed. It has been shown that in a particular case of a head-on collision of an electron with a low intensity wave when one photon is absorbed, the cross section of the process under investigation in the superhigh energy range increases according to a logarithmic law up to a value which is substantially greater than the cross section of the process $e^++e^-\to Z+H$ that takes place under similar conditions.

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## On electron polarization in a pulsed electromagnetic field

### A.E. Lobanov

Moscow University Physics Bulletin 1997. 52. N 2. P. 85

The Dirac-Pauli equation for an electron in a plane-wave field has been studied. Precise solutions to this equation have been obtained for fields of a special shape.

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Atomic and nuclear physics

## Detection of neutrons and $\gamma$-quanta under laboratory conditions and their separation by the scintillation pulse shape in CsI(Tl)

### A.V. Bogomolov, I.N. Myagkova

Moscow University Physics Bulletin 1997. 52. N 2. P. 88

Atmospheric neutrons and $\gamma$-quanta have been recorded separately under laboratory conditions with the aid of a CsI(Tl) scintillation crystal. The secondary charged products of interaction between neutrons and $\gamma$-quanta and the crystal material were identified by pulse shape in CsI(Tl). This technique allows one to detect a neutron flux (with energies $E_n>20$ MeV) of about $\sim 10^{-3} particles\cdot см^{-2}s^{-1}$ against a background of a $\gamma$-radiation flux which is an order of magnitude higher.

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## Three-dimensional radiometric model of a periodically perturbed water surface in the millimeter wave range and its experimental verification

### V.V. Gladun, S.E. Petukhov, Yu.A. Pirogov, D.A. Tishchenko

Moscow University Physics Bulletin 1997. 52. N 2. P. 92

A three-dimensional model has been developed for self-radiation of a periodically perturbed water surface. The model is based on the perturbation method and allows one to obtain the spectrum of surface waves with the aid of non-contact measurements. The experimental data obtained for the case of two waves on the surface coincide with theoretical results to sufficient accuracy.

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Optics and spectroscopy

## Field distribution in the focal area of the Talbot cylindrical cavity

### V.P. Kandidov, A.V. Kondrat'ev

Moscow University Physics Bulletin 1997. 52. N 2. P. 96

The distribution of the field formed by a laser lattice in the focal plane of the Talbot cylindrical cavity has been studied. A formula has been proposed for calculating the Talbot distance in a cylindrical geometry.

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Geophysics

## Directivity of dispersive tsunami radiation and specific features of sea floor motion in the focus area

### M.A. Nosov, S.V. Mironyuk, N.K. Shelkovnikov

Moscow University Physics Bulletin 1997. 52. N 2. P. 99

The process of tsunami generation by piston-like and membrane-like sea floor motions in an asymmetric focus area is investigated within the framework of linear potential theory. It was demonstrated that the wave radiation directivity and the total energy transmitted from the moving ocean sea floor depend essentially on the character and temporal law of sea floor motion in the focus.

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