Stark broadening of In III, Tb III, and Pb IV spectral lines

Using a semiclassical approach, the authors consider the widths and shifts of spectral lines for twenty In III and two Tl III multiplets initialed by collisions with electrons, protons, and ions of helium at a density of the perturbing particles of 10¹⁷ cm⁻³ and temperatures from 20,000 to 500,000 K. For two Pb IV multiplets, the widths and shifts of spectral lines produced by collisions with electrons, protons, and ions of He III at a density of the perturbing particles of 10¹⁷ cm⁻³ and temperatures from 50,000 to 1,000,000 K are considered similarly. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 753–757, November–December, 1999.     

The radiant characteristics of quantum-dimensional laser structures in the GaAs/GaAlAs system

It is shown that allowance for the dependence of the intraband relaxation time on the laser operation regime in the model of the burning-out of a spectral hole makes it possible to obtain a better agreement between experimental and theoretical spectral characteristics. Reported at the 3rd Belarusian-Russian Seminar “Semiconductor Lasers and Systems Based on Them,” Minsk, June 22–24, 1999. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 536–538, July–August, 2000.     

Stark broadening of ar VIII spectral lines

Using the semiclassical perturbation method, we consider, for nine Ar VIII transitions, widths and shifts of spectral lines that are due to collisions with electrons, protons, and ions of He III ut a perturbing particle density of 10¹⁸ cm⁻³ and temperatures between 200,000 and 3,000,000 K. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 286–288, May–June, 2000.     

Populations of argon metastable states in an argon-silane plasma of a high-frequency electric discharge

We have determined the absolute populations of argon metastable states in the plasma of a high-frequency discharge in a pure argon atmosphere and in a mixture of argon and silane. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 733–736, September–October, 2008.     

Dependence of the spectral characteristics of quartz on the fluence of neutrons

The influence of radiation on the change in the optical properties of a crystalline quartz is investigated. The results of the measurement of the optical spectra of luminescence, reflection, and scattering in specimens irradiated with different fluences of neutron radiation are presented. It is shown that the corresponding spectral characteristics experience substantial changes in the region of fluences that are associated with rearrangement of the crystalline structure. The results of approximation of some radiation kinetics are given, and the trend in the process of accumulation of disordered zones is established. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 543–545, July–August, 2000.     

High-resolution measurements of pressure self-broadening and shift for the metyl-cyanide rotational J=1−0 line

Summary The capabilities of the travelling-wave spectrometry in the field of high-resolution measurements of low-pressure gases at microwave frequencies are discussed. Some details about the main aspects of the experimental procedure and the data management, useful for the improvement of overall performances, are specified. A pressure broadening of (72.5±1.5) MHz/Torr and a pressure shift of (4.3±0.3) MHz/Torr are measured for theJ=1−0 rotational line of CH₃C¹⁴N. These results are more accurate than those previously reported and in better agreement with the theoretical predictions.

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Riassunto Si discutono le prestazioni di uno spettrometro a microonde ad onda progressiva nel campo della spettroscopia ad alta risoluzione in gas a bassa pressione. Sono in particolare considerati alcuni aspetti delle procedure sperimentali e dell'elaborazionedei dati che hanno portato a decisi miglioramenti nella sensibilità e nelle prestazioni complessive dell'apparato sperimentale. Sono stati misurati per la riga rotazionaleJ=1–0 di CH₃C¹⁴N un coefficiente di autoallargamento per pressione di (72.5±1.5) MHz/Torr e uno shift di (4.3±0.3) MHz/Torr. Queste misure risultano piú accurate di quelle precedentemente riportate e in migliore accordo con le previsioni teoriche.

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Резюме Обсуждаются возможности использования микроволнового спектрометра со скользящей волной для измерений с высоким разрешением в газах при низких давлениях. Рассматриваются основные аспекты экспериментальной процедуры и обработки данных, которые позволяют улучшить чувствительность аппаратуры. Измерены величины самоуширения с давлением (72.5±1.5) МГц/Тор и сдвига с давлением (4.3±0.3) МГц/Тор для ротационной линииJ=1–0 для CH₃C¹⁴N. Полученные результаты являются более точными, чем ранее опубликованные, и лучше согласуются с теоретическими предесказаниями.

     

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.     

Spectral-linewidth measurement with intracavity compensation for selective losses

We propose an intracavity method of determining the spectral linewidth based on the use of a special mode of operation of a laser with a magnetized atomic absorbing medium in an anisotropic cavity when the output radiation power of the laser does not depend on the optical density of the absorbing medium. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 283–285, May–June, 2000.     

Stark Broadening of F III Lines in Laboratory and Stellar Plasma

Using a semiclassical approach, we have considered electron-, proton-, and ionized helium-impact line widths and shifts for the F III 2p^{3 4}S^o-3s ⁴P resonant line. Moreover, for 10 F III multiplets where the full semiclassical perturbation approach is not applicable in an adequate way due to the lack of reliable atomic data, electron-impact line widths have been calculated within the modified semiempirical approach. Results are obtained as a function of temperature for perturber density of 10¹⁷ cm⁻³. The theoretical data obtained have been used to consider the influence of Stark broadening for A-type star atmosphere conditions. __________ Published in Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 412–415, May–June, 2005.     

Simulation of the contours of spectral lines of closed-ARC radiation

Simulated contours of self-reversed lines of Tl at 535 nm (7²S_1/2−6²P_3/2) and 378 nm (7²S_1/2-6²P_1/2) in alternating-current closed-arc radiation in mercury vapor with an addition of Tll were compared with experimental contours. It is shown that while a single self-reversed contour has many different sets of model parameters that ensure coincidence of experimental and calculated profiles, in the case of operation with a large data file of contours that correspond to different directions of observation along chords perpendicular to the discharge axis, and with different lines that have a common level, such a set of parameters becomes virtually unique. Instantaneous spatial distributions of Hg and Tl atoms in the ground state and of Tl atoms in the 6²P_3/2 state are determined and the parameters of the van der Waals broadening of the 7²S_1/2 level are found. It is shown that a considerable “red” shift of absorption contours in the outer layers of the discharge is observed. The results obtained contradict the presumed existence of local thermodynamic equilibrium in the given discharge. Reported at the Conference “Plasma Physics and Plasma Technologies,” Minsk, September 15–19, 1997 Petrozavodsk State University, 33, Lenin Ave, Petrozavodsk, 185640, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 761–768, September–October, 1998.     

Infrared filters and analyzers of the composition of substances based on them

Results of investigations on designing band dispersion and dispersion-interference filters for the 4–30 μm IR range and cutoff filters for the 50–300 μm region are presented. Analyzers of the composition of a substance that are designed on the basis of band IR filters and analysis procedures are described. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 734–744, September–October, 1998.     

Spectral and polarization properties of a composite material with filler of plant origin

Based on a filler of plant origin, we have developed a new composite material and have studied its spectral and polarization properties. We suggest a direction for application of the synthesized material. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 419–421, May–June, 2008.     

Temperature dependence of the width of spectral holes: Octaethylporphin in polymer matrices

Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 145–150, March–April, 1995.     

Analysis of an Inhomogeneous Semitransparent Plasma by the Lines in the Emission Spectrum

Using the methods of numerical simulation, we have investigated the dependence of the intensity and parameters of the spectral line profiles in the radiation of semitransparent plasma on its optical thickness, the degree of inhomogeneity, and the parameter distribution. As a model, we used the equilibrium plasma of argon with a given temperature profile on the observation line. The calculation has been performed for the spectral lines of the argon atom characterized by different broadening constants. On the basis of the results obtained it has been shown that it is possible to diagnose the plasma and determine the degree of its inhomogeneity and reabsorption by the parameters of the self-reversed profiles of the spectral lines. To diagnose the plasma in the absence of self-reversal, we propose to use the line intensities in the emission spectra of the plasma, including those obtained by probing it by its self-radiation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 404–411, May–June, 2005.     

Excitation cross sections for a vanadium atom

Moscow Power Engineering Institute, 14 Krasnokazarmennaya Str., Moscow, 105835, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 16–21, November–December, 1995.     

Specific features of complete-absorption measurement in selective intracavity laser spectroscopy

For multimode pulsed dye lasers (of nanosecond and microsecond duration with frequency-dependent losses in the cavity), experimental studies and theoretical calculations have been made of the dependence of the value of the equivalent line width, used as a measure of selective absorption, on the main parameters characterizing the laser, the cavity, and the absorbent. Analytical relations have been obtained which describe the main aspects of complete absorption in lines with dispersion, Gaussian, or mixed spectra profiles, and their experimental testing has been carried out. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 327–332, May–June, 2000.     

Inert gases’ collisional broadening and shift of thallium rydberg states

Summary The broadening and shift of thallium 6P _1/2–10P _1/2,3/2 transitions perturbed by argon and helium gas have been measured by two-photon Doppler-free absorption and ionization detection. Broadening and shift coefficients for He+Tl and Ar+Tl are obtained and van der Waal constants are determined.

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Riassunto L’allargemento e lo spostamento delle transizioni 6P _1/2–10P _1/2,3/2 del tallio disturbate dai gas argon ed elio sono statimisurrrati da un’osservazione di assorbimento e ionizzazione in assenza di effetto Doppler a due fotoni. Si ottengono i coefficienti di allargamento e spostamento per He+Tl e Ar+Tl e si determinano le costanti di van der Waals.

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Резюме Измеряются уширение и сдвиг 6P _1/2–10P _1/2,3/2 переходов в таллии, возмущенном аргоном и гелием. Получаются козффициенть уширения и сдвита для He+Tl и Ar+Tl. Определяются постояннйе ван дер Ваальса.

     

Filtration of IR radiation by three-component polymer-crystalline systems

We have investigated the regularities in forming the spectral characteristic of three-component polymeric-crystalline polytetrafluorethylene-Ge-LiF interference systems in the wide IR spectral region 0.8–160 μm. The efficiency of suppressing short-wave radiation by structurally asymmetric imerference systems consisting of polytetrafluorethylene and quasihomogeneous layers with a high refractive index is shown. Two of this kind of three-layer systems are sufficient for suppressing background radiation within the wavelength interval from the visible range to ∼35 μm owing to multiple reflection at the boundaries of elementary Ge and LiF layers that form quasihomogeneous layers (λ ∼ 1.7–17.0 μm) and also due to absorption in the Ge (λ<1.7 μm) and Lif (λ ∼ 17–35 μm) layers. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No_ 3, pp. 379–381, May–June, 2000.     

Glow discharge in helium at atmospheric pressure as a source of spectrum excitation

Self-maintained glow discharge at atmospheric pressure in a helium flow is used as an excitation source of spectra for analysis of the metals Na, Ca, Pb, Cd, and Zn in aqueous solutions of their salts. The intensities of the analytical lines of these metals are obtained as a function of the concentration, and the detection limits for each element are determined. Deceased. Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Misnk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 711–715, November–December, 1997.     

Spectroscopic characteristics of single dibenzanthanthrene molecules isolated in a low-temperature naphthalene matrix

With the use of the methods of single-molecule spectroscopy the authors determined homogeneous widths of the band of a pure electron transition of individual impurity centers of dibenzanthanthrene in a naphthalene matrix and the character of their temperature dependence. The high level of the fluorescence signal and the photostability of the impurity enabled the authors to determine using an autocorrelation procedure the rate constants of intercombination conversion and decay of the triplet state and to observe the process of spectral diffusion for a number of impurity centers. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 323–330, May–June, 1999.