Relative Intensities Of Spectral Lines Research Articles

Atomic Data and Spectral Line Intensities for Fe X

Electron impact collision strengths and spontaneous radiative decay rates are calculated for the important astrophysical ion Fe X. The data pertain to the 54 levels of the configurations 3 s 23 p 5, 3 s3 p 6, 3 s 23 p 43 d, and 3 s3 p 53 d. Collision strengths are calculated at five incident electron energies: 9.0, 18.0, 27.0, 36.0, and 45.0 Ry. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients (cm 3 s −1), i.e., the collision strengths integrated over a Maxwellian electron energy distribution, and then solving the equations of detailed balance for the populations of the 54 energy levels, assuming a collisional excitation model and an electron temperature of 1.0 × 10 6 K. This temperature is typical for Fe X when formed in equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are given in this paper. We also investigate the effects of proton excitation and solar radiative excitation on the level populations and line intensities. Finally, the calculated relative line intensities are compared with experimental solar intensities where available, and two good electron-density-sensitive line ratios are discussed. One result of the comparison is the identification of four unidentified solar spectral lines as Fe X transitions: 220.86, 226.32, 238.71, and 324.71 Å.

Spectroscopic measurements of laser induced plasma during welding with CO2 laser

Results of spectroscopic measurements of laser-induced plasma under welding conditions are presented. Welding was performed with the use of a continuous-wave CO2 laser operating at a power of 2 kW. Argon or helium was used as a shielding gas. The welding metal was stainless steel or titanium. Emission spectra from plasma were measured with a spectrograph and 1254 Silicon Intensified Target detector connected to the optical multichannel analyzer. The plasma electron temperatures were determined from the relative intensities of spectral lines and the electron densities were determined either from Stark broadening of atomic line or the absolute intensity of ionic line. The distributions of the electron temperature and density over the metal surface are presented and the influence of a shielding gas on plasma parameters is demonstrated. The plasma parameters obtained were used to calculate the absorption of a laser beam in the plasma over the metal surface. No significant absorption was found in our experimental conditions.

Excited-state populations of hydrogenlike and heliumlike ions and diagnostics of dense transient plasmas from the relative intensities of spectral lines

A collisional-radiative model of H- and He-like ions is constructed. The model allows a determination of excited-state population densities for arbitraryN e ,T e , and ion composition. The coefficientsr 0 andr 1, the collisional-radiative ionization and recombination coefficients for H-like ions and for the He-like ions F VIII and Mg XI are calculated. The methods of plasma diagnostics from the relative intensities of spectral lines are substantiated. It is indicated that the possibility of measuringN e from the resonance-to-intercombination line intensity ratio of a [He] ion is determined by the knowledge of the ion composition andT e .

Determination of phosphorus in borophosphosilicate or phosphosilicate glass films on a silicon wafer by wavelength‐dispersive x‐ray spectrometry

AbstractA wavelength‐dispersive x‐ray fluorescence method was developed for the determination of phosphorus in borophosphosilicate glass (BPSG) or phosphosilicate glass (PSG) films on a silicon wafer. Secondary spectral line intensities from the coated wafer are compared with those of an uncoated Si wafer and a fused P standard. The results are then converted to phosphorus content and surface density of the film by equations for the relative spectral line intensities of P and Si with corrections for the shift in the Si peak due to chemical bonding. Results obtained on an annealed set of PSG samples using four different incident spectra were self‐consistent and correlated well with independent inductively coupled plasma atomic emission spectrometric analyses for phosphorus and ellipsometric measurements of thickness. Preliminary results with BPSG samples were promising and showed that results for phosphorus were not sensitive to boron concentrations in the films.

The measurement of vacuum-UV line intensities for neon-like ions generated in a θ-pinch device

The relative intensities of spectral lines from Δn = 0 transitions in 2p53l configurations of neon-like Ar8+ and Cl7+ are measured in a plasma generated with a θ-pinch device. Six of these lines involving 3p-3s transitions have exhibited significant amplification in high density plasmas of higher-Z elements, but with considerable disagreement compared to numerical predictions. Agreement in the present experiment indicated that the collisional excitation, mixing, and radiative decay in the modeling is accurate, at least for the ions measured. Data supporting this on 3d-3p as well as 3d-2p and 3s-2p transitions are presented. The emphasis here is on the measurements performed. For example, an essential instrumental relative intensity calibration by a branching ratio technique is described in detail.

トンネル分光によるギ酸イオンの表面配向

Inelastic electron tunneling spectroscopy (JETS) has been applied to investigate the orientational behaviour of formate ions adsorbed on the alumina surface of Al/Al2O3/Pb tunnel junction. The formate ions were introduced by external doping technique. The directions of the molecules relative to alumina surface are determined by the relative intensities of spectral lines taking advantage of the selection rule that JETS excites predominantly the vibrational mode parallel to the tunneling direction.As the coverage increased, the formate ions rotated by about 20 degrees and declined by about 10 degrees. It is also observed that the bias voltage has sensitive effect upon these surface conformation.

TWO-PHOTON RESONANT OPTICAL WAVE-MIXING AND PARAMETRIC PROCESSES USING POTASSIUM 5d 2DJ STATE

The, output of a pulsed dye-laser pumped by a frequency-doubled Nd: YAG laser is focused into a heat-pipe oven. The optical wave-mixing processes and parametric oscillations from two-photon excitation of 5d2DJ state in potassium vapor are investigated. Twenty-eight coherent lines within the range of 302-421 nm are generated. Splits and frequency shifts of the parametric oscillations and wavelengths and relative intensities of spectral lines in the wave-mixing processes are explained with a theoretical analysis based on the wave equation, atomic polarization and phase-match condition. The theoretical values are found to be in agreement with the experimental results.

Analysis of the intensities of line spectra of multiply charged ions in a laser plasma and their applications in calibration of spectroscopic instruments in far vacuum ultraviolet

An analysis was made of the distribution of the relative intensities of spectral lines with a common upper level in transitions of the 2s2pk+1–2pk+2 type in N-, C-, B-, and Be-like ions of Ca, Ti, and Fe excited in a laser plasma and recorded photographically by a glancing-incidence spectrograph. Use was made of theoretically calculated transition probabilities. The relative spectral sensitivity of a DFS-6 spectrograph used in combination with UF-4 photographic emulsions was determined as a function of the wavelength in the range 100–250 A. It was found that the dependence is nonmonotonic. The results were used in some diagnostic applications to laser plasma spectra.

Determination of some characteristics of spent fuel of boiling-water reactors using ? and ? spectrometry

The problem of identifying special nuclear materials (SNM) is given for detecting their possible illegal inclusion into the technological process. For this it is extremely useful to determine the relative content of the maximum number of nuclides of the actinoid elements, including nuclides of the transplutonium elements. The relative spectral line intensities resulting from emission of not one but several nuclides can also be employed. It becomes possible to employ dactyloscopy of a batch of SNM over the entire course of fuel reprocessing until it is used in new fuel elements. The problem can be simplified by artificial tagging of nuclear materials by small amounts of /sup 244/Cm, /sup 234/U, or /sup 233/U. In the authors' opinion, a combination of /alpha/ and /gamma/ spectrometry provides a good method for this kind of dactyloscopy of SNM.

ICP: D.c. arc in a new jacket?

The starting-point of this article is the common problem encountered in both inductively coupled plasma atomic emission spectrometry (ICP—AES) and d.c. arc AES when used for trace analysis, namely the extraction of a true net analyte signal from the composite radiation observed in the spectral window of an analysis line. In this connection the author points, first, to the wealth of data available in the literature on d.c. arc spectrography, which again is of topical interest in the further development of ICP—AES, and second, to the lack of data on the relative intensities of spectral lines emitted for ICPs, which makes it difficult to choose reliable analysis lines when the matrix elements yield complex spectra. The main topic of the paper is the description of an approach currently under development at Philips Research Laboratories, the eventual goal of which is to arrive at a new tabulation of spectral interferences for ICP spectra. Essentially the previous experience in converting intensities from the NBS Tables of Spectral-Line Intensities into ICP sensitivities is extended to the prediction of the degree of spectral interference using (a) ICP sensitivity ratios of analysis and interfering lines, (b) concentration ratios of analytes and interferents, (c) wavelength distances between interfering and analysis lines, and (d) the spectral bandpass of the spectrometer. Computer programs have been written for a general-purpose approach and a specific approach. In the general-purpose approach, a tabulation is created which can be consulted for any set of conditions as dictated by the spectral apparatus, the sample composition and the analytes. However, the user of the table has to look up each item of interest and to make decisions. In the specific approach, all decisions are built into the computer program. The user only formulates the matrix and upper limits of concentrations and a set of analytes and their lower concentrations of interest, and the computer program provides a set of the most sensitive analysis lines that are interference free under the specified conditions and gives the reasons for disqualification of other sensitive lines. In the general purpose approach, the sensitivity ratios and concentration ratios are taken into account by the so-called “critical concentration ratio”, defined as the ratio of the concentrations of interferent to analyte at which the ratio of the intensities of interfering line to analysis line within the spectral window of the analysis line is equal to unity. Wavelength distance and spectral bandpass are involved through the calculation of the areas of the Voigt profiles of analysis and interfering lines that fall within a spectral window the width of which is equal to the full width at half maximum of the “average” spectral line in the ICP spectrum. A discussion on the assignment of an appropriate value to the a-parameter of the Voigt profile is included. In the specific approach, the majority of the procedures of the general-purpose approach are used. However, the program computes, instead of critical concentration ratios, the intensity ratios of interferent to analyte lines for the concentrations specified. Examples of both approaches are presented in tabular form. The present status of the work is reviewed, and envisaged projects including experimental verifications and extensions are discussed. Various gross errors inherent in the conversion of the intensities of the NBS Tables of Spectral-Line Intensities are pointed out. Results of the calculations are used to illustrate the effect of spectral resolution of the spectral interferences and conclusions with respect to the resolution of spectrometers and the number of spectral windows required in ICP—AES are drawn. Linking up with earlier work of other investigators, the author finally points to the necessity of using state-of-the-art spectrometers in order to circumvent the adverse effects of straylight on the detection limits. Experimental results obtained with a 10-years old monochromator illustrate the disastrous effect of scattered radiation which occurs not only with Ca and Mg as main components, but with all major constituents that yield line-rich spectra or spectra with very intense lines.

X-ray plasma diagnostics

Results and methods are given for the investigation of hot laboratory and astrophysical plasmas parameters in a soft X-ray region 1 = 1-40 A. Line spectra of multiply charged ions are usually studied exper~mentally, and relative Intensities of spectral lines are measured. Achievements of modern physics of electronion collisions and theoretical spectroscopy make it possible to obtain for transient plasma the electronic temperature, density, ionization stage, and to investigate time and spatial distributions of these parameters. Introduction. X-ray spectroscopy of high temperature plasmas, as a new direction in plasma physics, has been developed recently by efforts of many scientists in different laboratories. This field deals mainly with line spectra of multiply charged ions in the spectrum region 1-40 A, and more hard adjacent continuous component is of interest. From physical point of view the X-ray plasma spectroscopy has the following background. In a case of ions with a high charge Z is> 1 any excitation decays mainly due to radiation. Other channels, both collisions and autoionization exist being well controlled corrections in comparison with radiative one. It leads to simple and understandable connections between spectral line intensities and mechanism of spectra formation. Modern physics of electronic and atomic collisions provides sufficient and accurate methods for calculations of cross sections and rate coefficients involving multiply charged ions. Theoretical spectroscopy has also reliable methods for classification and calculations of spectral lines in the X-ray region. Simultaneously, experimental technique has been developed with appropriate spectral, time and spatial resolution. It is worth noting that in the most of important cases low density astrophysical plasmas (electron density N, 5 1014 ~ m ~ ) and laboratory plasmas (N, 5 1020-1023 cmP3) are optically thin for the X-ray radiation. It helps much for interpretation of experimental results, and theoretical analysis. Therefore, the X-ray plasma spectroscopy contains three important parts : new sources and measurement methods of highly charged ion spectral data + physics of electronic and atomic collisions + theoretical spectroscopy of ions. For plasma physics the X-ray spectroscopy provides new and effective methods of contactless plasma diagnostics. It is essential that X-ray spectroscopy methods are equally valid for investigation both of astrophysical (active regions and Solar flares) and laboratory plasmas. At the present time this field has many hundreds of original papers and just few review publications. Among the latter papers [l-61 contain some systematization and extended list of references to earlier works. 1. Plasma parameters obtained from X-ray spectra. Multiply charged heavy ions are small impurities (much less than 1 %) in astrophysical plasmas and in stationary laboratory sources (Tokamak, Stellarator, etc.). Inertial plasmas produced by laser or electronic beams, plasmas of exploding wires and low-inductance sparks may be chemically homogeneous or consist of few heavy elements. X-ray spectroscopy provides universal diagnostic methods valid for all the cases mentioned. It is important to underline that plasma parameters can be obtained with the help of relative intensities of spectral lines, and one can avoid absolute flux calibration. Still absolute measurements provide the additional information (emission measure, etc.). Plasma parameters and types of spectral line used for the determination of them are listed in table I.

Influence of the anionic component of the additive on the relative intensity of atomic spectral lines in the analysis of dry residues from solutions

The dependence of the degree of enhancement of the relative intensity of spectral lines of In, Tl, V, Fe, Co, Cu, Be, Zn and Hg on the concentration of potassium salt additives was studied. This relationship usually displays a maximum, the magnitude of which depends on the nature of the element and, to a lesser extent, on the anion of the additive. For a given element the position of maximum enhancement is determined by the anion of the additive. The enhancement is greatest for elements with ionization potentials close to 6.5 V while suppression of line intensities occurs with elements with ionization potentials greater than 8.5 V. For all the elements studied the enhancement was greatest when using potassium halides as additives.

Intensity of Ar spectral lines in an Ar-O 2 glow discharge

Measurements of relative intensities of spectral lines and of plasma parameters have been carried out in an Ar-O 2 d.c. glow discharge under the following conditions: gas pressures of 1, 2 and 3 torr and partial pressures for O 2 of 0, 0.01, 0.02, 0.05 and 0.1 torr. Many of the Ar line intensities decreased when O 2 was added, while some were enhanced. Enhancement of the 6677A and 7504A lines has been most notable. The number density of metastable Ar atoms is decreased when O 2 is added. Upon addition of O 2, the electron temperature is decreased and the electron density increased, except at a gas pressure of 1 torr; the electric field strength in the positive column is also increased.

Infrared hydrogen emission lines in the spectra of Be stars

For the interpretation of observed hydrogen emission lines in the spectrum of γ Cas calculations of the relative intensities of spectral lines of the Balmer, Paschen, Brackett and Pfund series are carried out, by using the theory of moving stellar envelopes.

Interpretation of excitation temperature measurements in a cesium plasma

Electron densities and temperatures have been measured by using a Langmuir probe, as well as spectroscopic observations of continuum radiation and of spectral lines, in a cesium plasma. It is shown that the excitation temperatures determined from relative intensities of spectral lines do not always agree with electron temperature determinations. An interpretation of this discrepancy is proposed and discussed.

Choices of Spectral Lines and Published Ag-values in the Measurement of Excitation Temperature of Spectroscopic Light Sources

To secure a high degree of precision in the measurement of excitation temperatures from relative intensities of spectral lines, the choices of the lines and the best Ag-values deserveto be discussed.Twenty-three iron atom lines Which satisfy requirements for thermometric lines were chosen out of spectra in a wavelength range 3000 to 4000A.Excitation ternperatures of d.c. arcs and plasma jet flames were determined from the relative line intensities, which were obtained by a simplified procedure to calibrate the sensitivity of the emulsion over the wide range of wavelength, and the Ag-values cited from various literatures. A good agreement was found between the temperatures calculated with the Ag-values based on the NBS Monograph 53 and those with the Ag-values based on the American Institute Physics Handbook (second edition). This suggests that the Ag-values according to these literatures provide relatively reliable values of temperature. Line pairs and published Ag-values recommended for the practicable two-line method were also presented.

Stark broadening and shift of some isolated spectral lines of singly ionised earth alkaline metals

Using aZ pinch discharge as a plasma source the profiles and shifts of some prominent ion lines of earth alkaline metals were measured and compared with Stark broadening theories and other experimental results. An electron density of 3.1 to 10.3×1016 cm−3 was determined by the laser interferometry, while the electron temperature in the range 25100 to 34800 °K were measured from relative intensities of spectral lines. Comparison of reported experimental shifts and widths with the theories both semi-classical and quantum mechanical shows good agreement. It was also found that Griem's semi-empirical formula is useful and accurate for line widths evaluation.

Evidence for departures from equilibrium in an RF induction plasma in atmospheric-pressure argon

Spectroscopic observations are reported of an atmospheric-pressure argon plasma generated inductively by a high-power RF oscillator. Values of the excitation temperature T ex, obtained from measurement of the relative intensities of spectral lines, were substantially greater than temperature values T eq, determined from absolute continuum and line intensities on the assumption of local thermodynamic equilibrium (LTE). If a “collisional-radiative” plasma model is used, the absolute intensity measurements yield temperatures T cr, which are in better agreement with the T ex values.

The determination of relative intensities of spectral lines using a preliminary curve

The determination of relative intensities of spectral lines using a preliminary curve

A Convenient Technique for Determining the Relative Quantum Efficiency of a Monochromator and Detector System

A technique is described for determining the relative efficiency with wavelength of a monochromator and detector system using single photon detection. The method described utilizes a commercially available standard of spectral irradiance and provides a convenient, straightforward, and accurate technique for making the calibration, which is applicable over large ranges of wavelength and detector sensitivity. The calibration procedure has been designed to fill a need in atomic spectroscopy for a convenient method of determining the relative intensities of spectral lines in measurements which require single photon detection.