Electron-impact excitation cross-sections for the3 S 0−,3 P 0−, and3 D 0-States of a ruthenium atom

The excitation cross-sections of transitions of a ruthenium atom from the³ S ⁰−,³ P ⁰−, and³ D ⁰-levels are measured by the method of extended crossed beams. Based on the results of measurements, the excitation cross-sections of the states are calculated (ignoring cascade contribution). Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., Moscow, E-250, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 9–13, January–February, 1998.     

Excitation cross-sections of the4Do-levels of a cobalt atom under electron collision conditions

Cross-sections of the⁴D^o-levels of a cobalt atom are determined based on the results of measurements of 880 excitation cross-sections of the CoI spectral lines. Detailed calculations of branching and cascade population are made for the levels of the terms z⁴D^o, y⁴D^o, and x⁴D^o. Results of the present work and the cross sections calculated by R. K. Peterkop in the Born approximation are shown to be in good agreement. Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., Moscow, E-250, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 561–565, September–October, 1997.     

Formation of excited cesium ions in collisions of electrons with cesium iodide molecules

The process of formation of excited Cs ions in simple collisions of electrons with CsI molecules was investigated by the method of extended intersecting beams. Excitation cross sections measured for CsII spectral lines were used in the calculation of cross sections for excitation of energy levels. The contribution of cascade transitions to the total cross section for excitation of an energy level was determined for certain levels. Possible ways of formation of Cs^+* at low energies of the electrons are discussed. Moscow Power Engineering Institute, 14, Krasnokazarmennaya Str., E-250, Moscow, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 316–322, May–June, 1999.     

Dissociative excitation of a cesium atom in collisions of slow electrons with CsF molecules

The method of extended intersecting beams is used for studying inelastic collisions of electrons with cesium fluoride molecules. Forty-six cross-sections for dissociative excitation of the spectral lines of a cesium atom located in the spectral region 387–825 nm were used. The behavior of the sections in the spectral series of a cesium atom is investigated, which is reflected by a power law. The values of constants that are parameters in the power-law formula are determined. Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., E-250, Moscow, 105835, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 20–25, January–February, 1997.     

Two-electron excitation of calcium, strontium, and barium atoms on exposure to electron impact

The absolute effective excitation cross-sections for the spectral transitions of alkaline-earth atoms under the action of electron impact are determined, which correspond to simultaneous excitation of s²-valence electrons. The results were obtained on a setup with intersecting atomic and electron beams. It is established that the effective cross-sections of one- and two-electron excitation of valence subshells into states with the same effective principal and orbital quantum numbers are equal. The results obtained are compared with the available theoretical data. Institute of Electron Physics, National Academy of Sciences of Ukraine, 21 Universitetskaya St., Uzhgorod, 294016, Ukraine. Translated from Zhurnal Prikladnoi, Spektroskopii, Vol. 65, No. 3, pp. 433–436, May–June, 1998.     

Dissociation-induced excitation of CsII in collisions of electrons with CsOH molecules

Dissociation-induced excitation of a singly charged cesium ion taking place as a result of collisions of electrons with CsOH molecules is investigated. Possible reaction channels in the low-energy region are discussed. It is established that sequential population plays an important role for 6p levels of Cs⁺. Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., Moscow, 111250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 159–165, March–April, 1998.     

Excitation cross-sections of 3 F-and 3 F o-levels of barium atom by slow electrons

Excitation of the ³F-and ³F^o-levels of barium atom by slow electrons has been investigated experimentally. A total of 75 excitation cross-sections were measured at 30-eV electron energy; 20 optical excitation functions, in the range 0–200 eV electron energy. The behavior of cross-sections in some spectral series of BaI is discussed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 757–762, November–December, 2008.     

A Numerical Calculation for Electron Impact Excitation of Copper

The scattering of electrons by atomic copper has been studied using Born approximation and the concept of the generalized oscillator strength (GOS). Differential and total cross-sections for the excitation of the 3d¹⁰ 4p² P state are calculated at incident energies of 100 eV and are compared with other available experimental and theoretical data. The agreement between our calculation for the differential cross-section and the available experimental results is fairly good at the forward angles, while the agreement at large angles is poor. The calculated total cross-sections are compared with the experimental data and those predicted by several theories. It is found that our calculation for the total cross-sections are in a good agreement with the close coupling calculation of Msezane and Henry (1986a, Physical Review A 33, 1631) for incident energies greater than 20 eV. The integrated cross-section measurements of Ismail and Teubner (1995, Journal of Physics B: Atomic, Molecular and Optical Physics 28, 4164) are in good agreement with the present calculation.     

Muonium/muonic hydrogen formation in atomic hydrogen

The muonium/muonic hydrogen atom formation in μ^±−H collisions is investigated, using a two-state approximation in a time dependent formalism. It is found that muonium cross-section results are similar to the cross-section results obtained for positronium formation in e⁺-H collision. Muonic hydrogen atom formation cross-sections in μ^--H collision are found to be significant in a narrow range of energy (5 eV–25 eV).     

RX J0720.4-3125 as a possible example of magnetic field decay in neutron stars

We consider the possible evolution of the rotation period and magnetic field of the X-ray source RX J0720.4-3125, assuming that this source is an isolated neutron star accreting from the interstellar medium. The magnetic field of the source is estimated to be 10⁶–10⁹ G (the most probable value is about 2·10⁸ G), and it is difficult to explain the observed rotational period 8.38 s without invoking the hypothesis of magnetic field decay. For calculations we used the model of ohmic dissipation of the field in the core of the neutron star. Estimates for the accretion rate (10⁻¹⁴–10⁻¹⁶ M_⊙/yr), velocity of the source through the interstellar medium (10–50 km/s), and neutron star age (2·10⁹–10¹⁰ yrs) are obtained. Lomonosov State University, Moscow, Russia; loffe Physical and Engineering Institute, St. Petersburg, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 1, pp. 28–35, January, 1998.     

Calculation of the 1s–2s two-photon excitation cross-section in atomic hydrogen

The two-photon excitation cross-section of atomic hydrogen is calculated using explicit summation over intermediate states within the framework of dipole approximation. The matrix element for two-photon excitation is transformed into finite sums, consisting of the product of a radial and angular part. Nine intermediate states are employed in the calculation of the transition matrix element. The two-photon excitation cross-section obtained for the transition 1s ²S_1/2–2s ²S_1/2in atomic hydrogen is a good agreement with the literature.     

State selective electron capture in partially stripped ion-atom interaction at intermediate and high energies

Post form of “boundary corrected continuum intermediate state (BCIS)” approximation has been employed to study charge transfer cross-sections in collision of C^q+, N^q+ and O^q+ (q=1–5) with ground state atomic hydrogen in the energy range of 50–200 keV/amu. In this formalism we have adopted model potential for the interaction of the active electron with the projectile ion. Calculated results for total charge transfer cross-sections have significant improvement over other existing theoretical results in their comparison to the available experimental findings except for singly charge ions. Sub-shell distribution for total charge transfer cross-section has also been reported in graphical form. Predictions suggested by Olson in connection with the sub-shell distribution of total charge transfer cross-section has been reaffirmed. However, an oscillatory structure of charge state dependence of the total charge transfer cross-sections has not been found in the present investigation.     

Excitation of strontium atom in electron–atom collisions

The excitation of ³D levels of strontium atom by slow monoenergetic electrons has been studied experimentally. Thirty six excitation cross-sections were measured at 30-eV electron energy. Optical excitation functions for most of the transitions were recorded in the 0–200-eV electron-energy range. The excitation cross-section as a function of the principal quantum number has been found to correspond to a power law for all ³D series.     

The effect of oxygen on the excition spectra of A2B6 compounds

The exciton cathode luminescence and reflection spectra are studied for pure ZnSe with deviation from stoichiometry within a bilateral homogeneity region and a sharp change in the oxygen concentration from 3·10¹⁸ to 2·10²⁰ cm⁻³. It is confirmed that the exciton b and is not shifted and, consequently, that the forbidden band does not change with the oxygen concentration. This effect is interpreted on the basis of the interaction of oxygen with intrinsic point defects. It is found that dissolution, of oxygen enhances the excitonphonon interaction, which results in additional absorption within the A_ex-1LO or A_ex-2LO spectral region. It is shown that this effect is also characteristic of other compounds A₂B₆. Moscow Institute of Power Engineering, 14, Krasnokazarmennaya St., 111250, Moscow B-250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 3, pp. 394–399, May–June, 1998.     

Elaborate treatment of the inelastic collisions of positrons with alkali atoms and alkaline-earth positive ions using a restricted coupled-static approximation

Summary We present the results of a very elaborate investigation of the inelastic collisions of positrons with the ground states of the first four alkali atoms (³Li,¹¹Na,¹⁹K and³⁸Rb) and their electronically resemblant alkaline-earth positive ions,i.e. ⁴Be⁺,¹²Mg⁺,²⁰Ca⁺ and³⁹Sr⁺, respectively, using a restricted coupled-static approximation in which the reactance matrices are adjusted to be symmetrical. Our interest is concentrated on the calculation of the total elastic and positronium formation cross-sections and their behaviour in the low-energy region (below 10 eV for the atoms) or the regions above the positronium formation thresholds (when the ions are considered). Our results are the most accurate cross-sections expected from the approximation employed. They reveal, within their limits, the most important characteristics of these cross-sections and provide us with a satisfactory comparison between the main features of positron-atom and positron-ion collisions. Present address.     

Differential elastic cross-sections of excited exotic hydrogen atoms

Differential cross-sections for the elastic scattering of excited exotic hydrogen atoms by hydrogenic atoms are calculated for the first time. The calculations are performed for exotic atoms (μ a,π a; a=p,d,t) in the states with the principal quantum numbers n=2-10 at relative motion energies E=0.001-15 eV and at scattering angles ϑ =0–180^00B0;. This revised version was published online in August 2006 with corrections to the Cover Date.     

Limited volume thin film deposition on geometrically complicated substrates

In this paper we report a study on the elastic scattering of electrons by lithium and sodium atoms in the presence of circularly polarized resonant laser field within the framework of the two-state rotating wave approximation. The effect of laser on projectile electrons is described by Volkov states. The frequency of the laser field is chosen to match with the 2s–3p (3s–3p) transition frequency in lithium (sodium) atoms. The total and differential elastic cross sections with single photon exchange are calculated for intermediate energies (50–150 eV) and laser intensity (10⁷–10¹¹ W cm^-2). An erratum to this article can be found online at http://dx.doi.org/. An erratum to this article can be found at     

Observation of oriented 23 S 1 helium atoms in a sodium-helium plasma irradiated by polarization-modulated laser radiation

An experiment on the observation of spin polarization of metastable helium atoms interacting with optically oriented sodium atoms under continuous rf discharge conditions is described. Laser radiation with alternating-sign circular polarization, tuned to the resonance excitation of the 3² S _1/2–3² P _1/2 transition in Na atoms, is used as the source for optical pumping of ground-state sodium atoms. Pis’ma Zh. éksp. Teor. Fiz. 65, No. 5, 385–387 (10 March 1997)     

Radiation of pulsed and glow discharges in CCl4

The radiation of a pulsed-periodic discharge in CCl₄ has been investigated. Its spectrum is found to differ considerably from the spectrum of the glow discharge. It is found that ‖60% of the energy from the 215–650 nm region falls in the UV spectrum. Moscow Physicotechnical Institute, 9, Institutskii Per., Dolgoprudnyi, 141701, Moscow Region, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 302–305, March–April, 1998.     

Excitation of <Superscript>3</Superscript><Emphasis Type="Italic">F</Emphasis><Superscript>o</Superscript> levels of nickel atom by collisions with slow electrons

Electron-impact excitation of odd ³ F ^o levels of the nickel atom has been studied experimentally. A total of 45 NiI line emission cross-sections at 50-eV exciting-electron energy were measured. Eight optical excitation functions in the 0–200 eV electron-energy range were recorded.