Determination of the Local Parameters of a Cascade‐Arc Plasma by the Profiles of the Lines in the Radiation Spectrum

The transverse distribution of the plasma temperature in the positive column of a d.c. cascade arc in argon at atmospheric pressure has been measured. The measurements have been carried out by the conventional method involving the determination of the emissivity of plasma as well as directly from the radiation spectrum of the arc without recourse to the Abelian inversion. A theoretical and model justification of the applicability of the second method is given. The results of the determination of the temperature profile in the observation direction by the width and shift of the ArI 425.9nm line selected for the diagnostics are presented. An analysis of the data obtained supports the possibility of determining the temperature of an inhomogeneous, optically thin plasma from the profiles of lines in the emission spectrum.     

Investigation of the Spectral Line Intensities of the ν9 Band of the Trans-Conformer of Ethylene

Russian Physics Journal - The intensities of 740 vibrational-rotational lines of the ν9 fundamental band in the IR spectrum of the trans-C2H2D2 molecule are first analyzed. The...     

Calculation and Analysis of Self-Broadening Coefficients of Water Vapor Lines for the Spectrum Range of 0.7–14 000.0 cm–1

Optics and Spectroscopy - Within the framework of the semiclassical method, more than 30 000 self-broadening coefficients of absorption lines of water vapor γ have been calculated for...     

The Opacity of the Solar Spectral Lines of CII 133.5 nm

Because the intensity ratio between two spectral lines arising from the same upper level can depend on opacity, we determine the optical depth of the solar atmosphere CII emission at about 133.5 nm. By introducing the measured abundance of carbon and the results of ionization balance calculations, we estimate the line-of-sight physical thickness of the regions emitting CII lines at about 133.5 nm. This discussion will be significant in the analysis of the solar spectrum.     

Experimental Determination of Transmittance of Porous Cerium Dioxide Media in the Spectral Range of 300–1,100 nm

Abstract

A spectroscopy system is developed to measure radiative characteristics of participating media in the spectral range of 300–1,100 nm. The system incorporates a short-arc radiation source, double monochromator, optical chopper synchronized with a lock-in amplifier, and a silicon detector. Measurements of overall spectral transmittance are performed with two types of cerium dioxide samples with average porosities of 0.08 and 0.72, respectively. For both sample types, the spectral variation of the transmittance indicates mixed contribution by absorption and scattering to the observed attenuation in the considered spectral range. All samples are characterized by high opacity to radiation up to approximately 400 nm.     

Destruction of the Aluminum–Magnesium Alloy under the Influence of Pulsed Laser Radiation against Creep Conditions

Physics of the Solid State - Abstract—Using high-speed video recording, the stages of predestruction and development of a main crack initiated by pulsed infrared laser radiation on the...     

Influence of Indium on the Spectral and Structural Characteristics of Lu0.98 – xInxEu0.02BO3

Physics of the Solid State - The structure, IR absorption spectra, and luminescence spectra of orthoborates Lu0.98 ‒ xInxEu0.02BO3 at 0 ≤ x ≤ 0.1 has been...     

Topological Properties of the Born–Oppenheimer Approximation and Implications for the Exact Spectrum

The Born–Oppenheimer approximation can generally be applied when a quantum system is coupled with another comparatively slower system which is treated classically: for a fixed classical state, one considers a stationary quantum vector of the quantum system. Geometrically, this gives a vector bundle over the classical phase space of the slow motion. The topology of this bundle is characterized by integral Chern classes. In the case where the whole system is isolated with a discrete energy spectrum, we show that these integers have a direct manifestation in the qualitative structure of this spectrum: the spectrum is formed by groups of levels and these integers determine the precise number of levels in each group.     

Influence of Spectral Filtering and Nonlinear Gain on an Optical Soliton

Using the direct soliton perturbation theory, we investigate the evolution of soliton parameters and the firstorder correction of bright soliton in a system with linear and nonlinear gain （or loss） and spectral filtering in a comprehensive way. The results obtained by means of our analytic method are consistent with numerical simulations. It is also found that the stable soliton propagation which has been investigated in a previous report by others is the limit case of our results.     

Determination of the thickness and optical constants of amorphous Ge–Se–Bi thin films

The effect of varying bismuth concentration on the optical constants of amorphous Ge₂₀Se_{80? x} Bi _x (where x = 0, 3, 6, 9 and 12 at%) thin films prepared by thermal evaporation has been investigated. The transmission spectra T(λ) of the films at normal incidence were obtained in the spectral region from 400 to 2500 nm. An analysis proposed by Swanepoel [J. Phys. E: Sci. Instrum. 16 (1983) p.1214], based on the use of the maxima and minima of the interference fringes, was applied to derive the real and imaginary parts of the complex index of refraction and also the film thickness. Increasing bismuth content was found to affect the refractive index and extinction coefficient of the Ge₂₀Se_{80? x} Bi _x films. Optical absorption measurements show that the fundamental absorption edge is a function of composition. With increasing bismuth content, the refractive index increases while the optical band gap decreases.     

Influence of CuO and sintering temperature on the microstructure and magnetic properties of Mg–Cu–Zn ferrites

The synthesis of a series of Mg–Cu–Zn ferrites with the substitution of Cu for Mg has been obtained by solid-state reaction method. Microstuctural and structural analyses were carried out using a scanning electron microscope and X-ray diffraction (XRD), respectively. The lattice parameter is found to increase with increasing copper content. A remarkable densification is observed with the addition of Cu ions in the ferrites. Microstructural analyses indicate that CuO influences the microstructure of the ferrites by the formation of liquid phase during sintering. The grain size significantly increases with increasing copper content. Exaggerated grain growth is observed for the samples of x=0.25–0.35. The initial magnetic permeability (μ′) increases sharply with increasing concentration of Cu ions. This increase in μ′ is explained with the grain growth mechanism and enhanced densification of the ferrites. The resonance frequency of all the samples shifts toward the lower frequency as the permeability increases with Cu content. Sintering temperature T_s also affects the densification, grain growth and initial magnetic permeability of the samples.     

Global dynamical analysis of vibrational manifolds of HOCl and HOBr under anharmonicity and Fermi resonance:the dynamical potential approach

The vibrational dynamics of HOCl and HOBr between bending and OCl/OBr stretching coordinates with anharmonicity and Fermi coupling is studied with the classical dynamical potential approach. The quantal vibrational dynamics is mostly mapped out by the classical nonlinear variables such as fixed points, except for the state energies, which are quantized. This approach is global in the sense that the focus is on a set of levels instead of individual ones. The dynamics of HOBr is demonstrated to be less complicated. The localized modes along the OCl/OBr stretching coordinates are also shown to have O-Br bonds more prone to dissociation.     

Analysis of Methods of Investigation of the Vibration–Rotation Spectrum of Monomers and Dimers of Sulphur Hexafluoride Isotopes

Journal of Experimental and Theoretical Physics - The stability of the system of sulphur hexafluoride dimer SF6 under the action of external laser radiation has been estimated using ab initio...     

Spectral and Quantum‐Chemical Investigation of the Influence of the Spatial Structure of a Polymeric Complex on the Mechanism of Catalytic Oxidation of Sulfur Dioxide with Oxygen

Based on the calculations carried out by the ZINDO/S method, we suggest interpretation of the electronic absorption spectra of solvate complexes of cobalt with polyethyleneimine and sulfite ion. The quantumchemical analysis of the spectrophotometric data has shown that the change in a concentration of cobalt ions in a solution leads to conformation changes in a polymeric chain. The kinetic and quantumchemical investigation of the mechanism of catalytic oxidation of SO₃ ^2– to SO₄ ^2– is carried out. We suggest a spatial structure of the transient state that provides optimum conditions for the oxygenation reaction. The kinetic data indicate that the catalytic activity of cobalt ions fixed on a polymeric matrix is by three orders of magnitude higher than of their monomeric analogs. Using calculations performed by the RM3 method, we show that the oxygenation process is of exothermal nature and that there is a direct correlation between the reactionrate constant and the energy released in the process of oxygenation (E). On substituting ammonia molecules by a polyethyleneimine fragment, E increases by 39.39 kcal/mole.     

The Linearσ-model and the Observed Enhancement in the Mass Spectrum of pp in J/ψ→γpp

Provided the enhancement in the pp spectrum in radiative decay J/ψ→γpp observed by the BES collaboration is due to an existence of a pp molecular state, we calculate its binding energy and lifetime in the linear σ model. Concretely, we consider a possibility that the enhancement is due to a pp resonance which is in either S-wave or P-wave structure and compare our results with the data. Moreover, pp can annihilate at s-channel which is absent in deuteron, thus by studying the total width of the pp bound state, we may gain more information about the linear σ model and some concerned issues     

Influence of polarization and iron content on the transport properties of praseodymium–barium manganite

Polarization and iron effects on the electrical properties of Pr_0.67Ba_0.33Mn_1−xFe_xO₃ have been studied using impedance measurements. When iron is introduced, the insulator–metal transition (MI), observed in free compound, disappears and destroying such transition needs an iron concentration less than 5%. We also found that electrical conductance decreases when increasing Fe content. Such results are attributed to the decrease of Mn³⁺/Mn⁴⁺ ratio. Also, they are ascribed to the high probability of encountering Fe³⁺–O–Fe³⁺ and Mn³⁺–O–Fe³⁺ interactions, which greatly weakens the influence of Mn³⁺–O–Mn⁴⁺ interactions. The AC conductivity studies indicate that different types of hopping are involved. The contribution of hopping mechanism is confirmed by the temperature dependence of the frequency exponent ‘s’. Conductivity analysis shows that small polaron hopping (SPH) and variable range hopping (VRH) models are present in the conduction process. For small iron concentrations (x<0.1), we found that activation energy (E_a) does not changes significantly. Such result is in good agreement with the literature. But, for high iron concentrations (x>0.1), we found that E_a depend strongly in Fe content. We also found in this work that DC-bias does not affect the conduction process but proves its thermal activation. The variation of the conductance with polarization is a proof of an electro-resistance effect.