Dissociative excitation of the cesium atom in e-CsCl collisions

The dissociative excitation of the cesium atom in collisions of slow electrons with cesium chloride molecules is studied by the method of extended crossed beams with detection of the optical signal from the crossing region. Forty-seven cross sections for the excitation of spectral lines of CsI in the spectral region 347–852 nm are measured at an electron energy of 100 eV, and 10 optical excitation functions (OEFs) are recorded. It is found that the dependence of the excitation cross sections on the principal quantum number of the upper level in the spectral series of Cs I corresponds to a power law. The characteristic values of the constants in the power law are determined for each of the investigated series. Zh. Tekh. Fiz. 69, 29–34 (January 1999)     

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 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.     

Excitation of3 G 0-states of titanium, zirconium, and hafnium atoms by electron impact

Detailed information about excitation cross-selections of spectral lines of titanium, zirconium, and hafnium atoms obtained using extended crossed beams are used for calculation of the excitation cross-sections of the³G⁰-levels of these atoms. Results are compared with cross-sections calculated in Born’s approximation. For titanium: it is found that theoretical predictions agree well with experimental data. Differences found for zirconium are explained by the single-configuration approximation used in the calculation. Moscow Power Institute, Russia, 14 Krasnokazarmennaya St., 111250, Moscow E-250, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 707–710, November–December, 1997.     

Calculation of the characteristics of radiative multiphoton absorption and emission lines when an atom interacts with pulsed laser radiation

We have used the quantum electrodynamic theory of moments and the S-matrix formalism of Gell-Mann and Low to carry out numerical modeling of the characteristics (shift, width) of radiative multiphoton absorption lines for an atom in the field of a multimodal laser pulse with gaussian and soliton-like shapes. We have studied the effect of multimode character on the characteristics of multiphoton resonances, using as an example the 6S-6F transition in the cesium atom at the wavelength 1059 nm. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 271–274, March–April, 2007.     

Experimental determination of the rate constant for spin exchange in collisions of polarized metastable helium atoms with ground-state cesium atoms

The rate constant for spin exchange in a system consisting of a metastable helium atom and an alkali-metal atom is determined. An experiment on optical orientation of atoms established that the rate constant for spin exchange in a collision of a metastable 2³ S ₁ helium atom with a cesium atom in the 6² S _1/2 ground state equals (2.8±0.8)×10⁻⁹ cm³ s⁻¹. The rate constant for chemoionization of cesium atoms by metastable helium atoms was determined at the same time to be (1.0±0.3)×10⁹ cm³s⁻¹. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 3, 145–148 (10 August 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.     

TIC rectifier with output voltage phase control. I. Cesium thyratron with a low direct potential drop

The results of investigation of the ignition voltage for a low-voltage cesium arc and direct voltage drops in the discharge in cesium triodes with fine-mesh (∼0.2 mm) and coarse-mesh (∼2 mm) control grids are presented. It is shown that in a cesium vapor pressure range of 0.05–0.1 Torr and for discharge currents of 5–10 A/cm², direct voltage drops can be reduced to 0.7–0.5 V even for a fine-mesh grid. For a coarse-mesh grid whose holdoff voltage is sufficient for rectifying low voltages (∼15–20 V), direct voltage drops are almost the same as for a diode even for currents of 1 A/cm² and lower. The critical factor of holdoff voltage loss is the grid emission level (∼1 mA/cm²).     

Short-wavelength emission characteristics of a longitudinal bromine vapor glow discharge in a quartz tube

The output emission characteristics are presented in the spectral range 150–350 nm for a longitudinal bromine vapor glow discharge in a quartz tube (inner diameter 1.4 cm, interelectrode distance 10 cm). Pressure of the working mixtures: P = 0.2–1.0 kPa. The emission spectrum of the lamp based on an He-Br₂ mixture consists of the 163.3 nm and 157.6 nm spectral lines of the bromine atom and a system of molecular bromine bands (170–300 nm). The total power of UV-VUV emission of the lamp based on an He-Br₂ mixture is 5 W max for efficiency <10%. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 816–819, November–December, 2007.     

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.     

Electron impact excitation of high-lying states in the tungsten atom

The extended crossed-beam method has been used to study excitation of high-lying levels in the tungsten atom. 40 excitation cross sections of WI spectral lines have been measured for exciting electron energy 50 eV. Two optical excitation functions were recorded in the electron energy range 0–200 eV. The results obtained were used to calculate the total excitation cross sections of 24 odd WI energy levels. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 283–288, May–June, 2007.     

Radiative characteristics and kinetics of processes in low-pressure gas-discharge lamps based on a mixture of helium and iodine vapors

The UV radiation of glow- and capacitive-discharge lamps based on mixtures of inert gases with iodine vapors are optimized in the spectral range of 175–360 nm, in which working helium-iodine mixtures of different compositions are used. The most intense spectral lines in the bactericidal region of the spectrum were the atomic lines of iodine (183.0, 206.2 nm), and in the region of 320–360 nm, emission of the spectral band of an iodine molecule prevailed with a maximum at λ = 342 nm. For a capacitive lamp with a casing opaque in the spectral range λ < 250 nm, the main part of the plasma emission power is concentrated in the A′-D′ band of an iodine molecule with a maximum at 342 nm. The emission brightness of this lamp is optimized in iodine molecule transitions depending on the partial helium pressure. We present the results of simulating the kinetics of processes in a glow-discharge plasma in mixtures of He, Xe, and iodine vapors. We establish the dependence of the main part of the emission intensity of the 206.2 nm spectral line of an iodine atom and the 342 nm band of an iodine molecule on the helium pressure in a glow-discharge lamp operating on a He-I₂ mixture.     

Absorption measurements in dense cesium vapor using a UV–violet light-emitting diode

We present results of absorption measurements in a dense superheated cesium vapor generated in an all-sapphire cell using a UV–violet light-emitting diode as a continuum source. Due to the very effective thermal destruction of Cs₂ molecules, a number of diffuse and satellite bands appear around higher members of cesium principal series lines, which are not easily visible in saturated cesium vapor. From the temperature dependence of the diffuse features we can distinguish short-range singlet transitions from temperature-independent spectral features that stem either from a shallow lowest triplet state or from the long-range photo association spectra of triplet or singlet Cs₂ molecules. The limits of the present interpretation of the observed bands in the UV–violet spectral region are discussed. Received: 25 May 2000 / Revised version: 20 September 2000 / Published online: 13 December 2000     

Trends in the spectral distribution of the absorption coefficient of complex organic molecules

General trends in formation of the observed vibrational spectra are analyzed by calculating spectral distributions of the absorption coefficient in the IR region for 45 molecules of different classes ignoring the electrooptical paramaters of particular bonds and structural groups. It is shown that for many molecules, only vibrations of peripheral X-H bonds make a prevailing contribution to the total integral absorption in a wide spectral range. The effect of increasing intensities of some bands is clearly observed for skeleton vibrations, when optical parameters of external X-H bonds are zero. V. I. Vernadski Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, 19, Kosygin St., Moscow, 117975, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 4, pp. 491–496, July–August, 1998.     

Emission properties of a pulsed-periodic barrier discharge initiated in helium-iodine and argon-iodine mixtures

The subject of investigation is the emission properties of a pulsed-periodic barrier discharge initiated by submicrosecond pulses (f = 40–1000 Hz) in He-I₂ and Ar-I₂ mixtures. The investigation is carried out in the spectral range 200–400 nm at a pressure of the working medium of 1–100 kPa and an iodine partial pressure of 130–200 Pa. The dependence of UV emission from the plasma of the barrier discharge at the 342 nm I₂(D′ → A′) band and the iodine atom spectral line at 206.2 nm on the argon and helium partial pressures, excitation pulses repetition rate, and charging voltage of the capacitor of a short high-voltage pulse modulator is optimized. The contribution of the 206.2 nm I* spectral line to the UV emission of the barrier discharge is estimated.     

Determination of electrooptical parameters of molecules with the use of nonempirical quantum-chemical calculations of absolute intensities of absorption bands in the IR region

The authors verified the possibility of more accurate determination of electrooptical parameters (EOP) obtained in quantum-chemical calculations by solution of the inverse spectral problem for different molecular species. Intensities calculated with the ab initio method are taken as reference quantities. V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, 19 Kosygin St., 117975, Moscow, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 19–24, January–February, 1999.     

Detection of a sulfur dioxide radio line ν∼131 GHz in the lower troposphere

We present the results of detection of the sulfur dioxide radio line ν∼131 GHz of anthropogenic origin in the lower troposphere emission. The methods and results of spectral radiometric studies of SO₂ content near its sources are described. Institute for Space Research, Moscow; Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 6, pp. 704–712, June, 1997.     

Computer simulation of the structure of liquid cesium and determination of the pair potentials over a wide temperature range

Using diffraction data for liquid cesium structure over a wide temperature range, models of liquid cesium are constructed and the effective pair potentials are extracted using the theory of liquids. The iterative procedure proposed by L. Reatto is used. In the range 323-1923 K the pair potentials are weakly temperature-dependent. The potentials extracted from the diffraction data differ from the potentials calculated using the Animalu-Heine pseudopotential. The self-diffusion coefficients in liquid cesium are determined. Their temperature dependence is described satisfactorily by a power-law function. Zh. éksp. Teor. Fiz. 115, 50–60 (January 1999)     

Grazing incidence systems with multiple reflections

The theory of turning soft x-ray SXR radiation beams by means of concave surfaces through multiple reflections (the “whispering-gallery” effect) is developed. It is demonstrated that concave mirrors are capable of turning an SXR beam by an arbitrary angle determined by their aperture angle. The reflectivities are of the same order of magnitude as those of multilayer mirrors (20–80% at a turn by 90°). The turning mirrors feature a wide spectral transmission band (Δλ ∼ λ). The potentialities of concave mirrors and hollow cylindrical waveguides with respect to concentration and collimation of SXR radiation are considered. The requirements imposed on the smoothness of the reflecting surfaces are obtained and the optimal (as to their optical properties) materials are chosen for their fabrication. The theoretical results are compared to experimental data. Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva (Proceedings of the Lebedev Physical Institute, Russian Academy of Sciences, Moscow), Vol. 196, pp. 143–167, 1989.     

Output characteristics and parameters of the plasma from a gas-discharge low-pressure ultraviolet source using helium-iodine and xenon-iodine mixtures

The output characteristics and parameters of the plasma of a powerful gas-discharge source of UV radiation are studied. The UV source uses He-I₂ and Xe-I₂ mixtures and is excited by a longitudinal glow discharge. The pressure of the gas mixtures is varied from 100 to 1500 Pa, and the discharge power falls into the range 15–250 W. The source (lamp) emits in the spectral interval 200–390 nm, which covers the spectral line of the iodine atom at 206.2 nm, the spectral band of XeI(B-X) with a maximum at 253 nm, and the spectral band of with a maximum at 342 nm. For He(Xe)-I₂ mixtures at a pressure of 800–1000 Pa (this pressure range is near-optimal according to our experimental data), the electron energy distribution functions and the electron kinetic coefficients as functions of parameter E/N (E is the electric field strength, and N is the particle concentration in the discharge) are calculated. The calculated plasma parameters are used in the qualitative analysis of key electronic processes in the plasma of an exciplex halogen UV source and will be subsequently employed in numerical simulation of the process kinetics and output characteristics of a UV source based on helium-iodine or xenon-iodine mixtures.