Wavelengths Of Spectral Lines Research Articles

Evaluation of uncertainties in atomic data on spectral lines and transition probabilities

The present article discusses some recent advances in methods of critical evaluation of experimental data on wavelengths of spectral lines and theoretical data on transition probabilities and oscillator strengths for atoms and atomic ions. In particular, recently developed new statistical approaches to estimation of uncertainties of weighted means of multiple measurements are described, and a numerical toolbox implementing these new approaches is presented. There are also some new developments in estimation of uncertainties of theoretical transition probabilities. A short review of literature implementing these new procedures is provided, including a description of the methodology.Graphical abstract

The quality monitoring of paracetamol medicament using a noninvasive microwave sensor

Environmental conditions, including temperature, humidity, and light, can impact the quality of drugs. Microwave-based approaches offer a fast and cost-effective way to detect quality variations, providing an alternative to traditional techniques in the pharmaceutical and cosmetic industries. This article proposes the use of a microwave sensor for monitoring the quality of pharmaceutical drugs at distinct temperature levels. A small planar sensor based on three hexagonal split ring resonators (TH-SRR) is fabricated. The design is manufactured on an FR-4 dielectric substrate. The sensor is tested on a 1000 mg paracetamol tablet, at temperatures ranging from 40 to 80 ^circC. The Variation in the permittivity that characterizes product degradation is translated into a shift in the frequency of the scattering matrix elements. To validate the microwave approach, drug quality is examined with the laser-induced breakdown spectroscopy (LIBS) technique, an optical emission laser used for both qualitative and quantitative investigations of elements contained in a sample. The existing elements are classified using the National Institute of Standards and Technology (NIST) database and categorized according to their spectral line wavelengths. The experiments show the presence of optimal wavelength values for carbon (C), hydrogen (H), nitrogen (N), and oxygen (O) at 247.92 nm, 656.49 nm, 244.23 nm, and 777.48 nm, respectively. The microwave experimental results show a shift frequency of approximately 1 MHz on average when the tablet is heated at 80 ^circC for 15 min. Meanwhile, the LIBS measurement shows a remarkable shift in terms of intensity of approximately 8884 and 812 for carbon and hydrogen, respectively. Understanding how paracetamol dries under high temperatures and improving the process settings of the microwave sensor are investigated and assessed in this work.

Precision Measurements of X-Ray Spectra for the Diagnosis of Laboratory Astrophysical Plasma

A technique is described for achieving high accuracy (relative error up to ≈0.001%) for measuring the absolute wavelengths of the spectral lines of multiply charged ions with an average (Z = 17–25) by the nuclear charge, the spectra of which can be used for plasma diagnostics in laboratory astrophysics experiments. It is based on irradiation with subnanosecond laser pulses with an intensity of 1015–1016 W/cm2 targets with a multicomponent chemical composition, including atoms with both medium and low Z. The presence of the latter ensures the presence in the emission spectrum of the resulting laser plasma of lines of hydrogen-like ions used as references. An atomic-kinetic code was created, and the intensities of possible reference and investigated spectral lines were calculated. The principles of selecting the target material, the features of the implementation of the technique on the example of a focusing spectrometer with spatial resolution based on spherically curved mica and α-quartz crystals are considered, and specific parameters of spectrometer circuits and types of targets for precision measurement of the wavelengths of spectral lines of helium- and lithium-like ions with nuclear charges Z = 13–25 are given. The results obtained in this work will be used in the planning of fundamental X-ray spectral studies at the ELF laser facility being developed at MEPhI.

Analytical capabilities of the Grand-2000 high-resolution spectrometer

The analytical characteristics of the new Grand-2000 high-resolution spectrometer with BLPP-4000 photodetectors were evaluated. The device was tested as part of the Grand-Potok complex, which consists of a spectrometer and an electric arc facility and is designed to analyze powder samples continuously brought into the plasma atomizer (free-burning arc in air). The characteristics of the new spectrometer were compared with those of the Grand spectrometer, which is widely employed in analytical laboratories. It is shown that the use of the Grand-2000 spectrometer to determine the concentration of elements in geological and industrial powder samples does not lead to an obvious improvement in the results. The threefold increase in the spectral resolution of the new spectrometer reduces spectral influences from interfering elements, but the relative systematic error both decreases and increases for different samples. This may indicate the influence of unaccounted-for factors, for example, non-optimal spectra processing algorithms for this device. The results obtained suggest good prospects for the use of the Grand-2000 spectrometer to determine the concentration of elements in samples with a complex spectrum, but they also indicate the need for further studies to determine the optimal parameters for processing spectra. In addition, the Grand-2000 spectrometer can be used to supplement and refine the existing database of the wavelengths of spectral lines.

Precise wavelength measurements of potassium He- and Li-like satellites emitted from the laser plasma of a mineral target

Atomic models of high-Z multicharged ions are extremely complex and require experimental validation. One way to do so is to crosscheck the predicted wavelengths of resonance transitions in He- and Li-like ions against precise spectroscopic measurements that use the spectral lines of H-like ions for spectra calibration; these reference data can be modeled with outstanding precision. However, for elements with Z of at least 15, it is quite difficult to create a hot dense plasma with a large concentration of H-like charge states. To mitigate this issue, the suggestion here is to use as laser targets particular minerals comprising elements with moderate (between 15 and 30) and low (less than 15) Z, with emission from the latter delivering perfect reference lines over a whole range of He- and Li-like moderate-Z emission under examination. This approach is implemented to measure the wavelengths of resonance transitions (1snp → 1s2 for n = 2, 3) in He-like K ions and their dielectronic satellites by irradiating plates of orthoclase (KAlSi3O8) with 0.5-kJ subnanosecond laser pulses. X-ray spectra of the laser-generated plasma contain the investigated lines of highly charged K ions together with precisely known reference lines of H-like Al and Si atoms. The K-shell spectral line wavelengths are measured with a precision of around 0.3 mÅ.

Spectral line list of potential cosmochronological interest deduced from new calculations of radiative transition rates in singly ionized thorium (Th ii)

ABSTRACTIn this work, we report a list of 91 strong Th ii spectral lines in the visible wavelength region that could be used as cosmochronometers in future investigations to determine stellar ages from thorium radioactive decay. This list was established on the basis of a pseudo-relativistic Hartree–Fock model including core-polarization corrections (HFR+CPOL) allowing us to compute the corresponding radiative decay parameters, the latter being found to be in good overall agreement with the most accurate experimental data when available. Besides this semi-empirical approach, the fully relativistic ab initio multiconfiguration Dirac–Hartree–Fock (MCDHF) method was attempted, showing large discrepancies with both the present HFR+CPOL and the most recent experimental oscillator strengths, although the calculated wavelengths from theoretical energy levels agreed with observed spectral line wavelengths within 2.4 per cent.

Visible light emission from surface of nickel bombarded by slow Xeq+ (4 q 20) ion

Bombarded by slow highly charged ion (SHCI), particles including ions and atoms of metal are excited and ejected from the sample. Optical emission can be observed for the radiative de-excitation of some excited atomic particles. The important information about particle ejection and incident ion neutralization, as well as the nature, the kinetic energy, and the number of the sputtered excited particles can be obtained by studying the optical emission process. The optical emission from the the collisions between slow (V~0.38 VBohr) highly charged Xeq+ (4 q 20) ions and high purity Ni (99.995%) surface is studied. The experiment is carried out at the 320 kV for multi-discipline research with HCIs in the Institute of Modern Physics, Chinese Academy of Sciences. The spectral lines are analyzed by using an Sp-2558 spectrometer equipped with a pattern of 1200 groves/mm blazed at 500 nm and an R955 photomultiplier tube at the exit slit. The target beam current corresponding to the dwell time is recorded, which can be translated into the incident ion current. Based on the formula of Y=N/(t/Ceq), the spectral line intensity is normalized. The normalized spectrum can be obtained from the interaction of 0.38VBohr Xe20+ ions with Ni surface in a wavelength range of 400-510 nm. The species at excited state can be identified by comparing the wavelengths of spectral lines with those in the standard spectroscopic table. Most of the observed spectral lines are identified as being from the electron transitions of Ni I 3d9(2D)4p-3d9(2D5/2)4d, Ni I 3d8(3F)4s4p(3P)-3d84s(4F)5s and Ni Ⅱ 3p63d9-3p63d8(3P)4s, as well as Xe I 5p5(2P3/2)6s-5p5(2P3/2)8p, Xe Ⅱ 5p4(3P2)6p-5p4(3P2)6d and Xe Ⅲ 5s25p3(2D)6s-5s25p3(2D)6p. Compared with the single charged ion, some neutralized incident ions yield Xe I, Xe Ⅱ, Xe Ⅲ spectral lines. The photon yields of spectral lines, such as Xe Ⅱ 410.419, Xe Ⅲ 430.444, Xe Ⅱ 434.200, Xe Ⅱ 486.254, Ni I 498.245, Ni I 501.697, Ni I 503.502, Ni I 505.061 and Ni I 508.293 nm, are presented each as a function of charge state of incident ion. The results show that the photon yield increases with the increase of the charge state, which is consistent with the potential energy of the incident ion. The potential energy is the driving force for photon emission of excited Ni atom. The neutralization of Xeq+ is in good agreement with that indicated by the classical over-the-barrier model.

Optical and electrical properties of capacitive coupled radio frequency Ar-H2 mixture discharge at the low pressure

In this study, the electrical and optical properties and plasma's parameters of capacitive radio frequency (RF) discharge for the argon and hydrogen mixture at low pressure are investigated using optical emission spectroscopy (OES) and a Langmuir probe. The wavelengths of spectral lines obtained from OES are between 400 and 950 nm. By using the spectral lines and probe data, the electron temperature for every different RF power, mixture rate and flow rate are determined by the modified Boltzmann curve method. The Langmuir probe gives the electron temperature and other plasma properties for the same discharge parameters.

Spectroscopic study and numerical simulation of low-pressure radio-frequency capacitive discharge with argon downstream

In this study, the characteristic properties and plasma parameters of capacitive radio frequency (RF) argon (Ar) discharge and supplementary discharge at low pressure are investigated with optical emission spectroscopy (OES). The wavelengths of spectral lines from OES are obtained between 650–900 nm. Using OES lines and related experimental data, the electron temperatures for different RF power, flow, and measurement periods are determined. Eventually, the properties of plasma including the electron temperature are identified. In addition, the numerical modelling of the discharge parameters is carried out by using the “extended” fluid model for plasma, and consistency between numerical and experimental results is discussed.

Iron multiplets in meteor comas

AbstractIn this paper, we present a catalog of the iron multiplets which are observed in meteor spectra. It contains the energy levels terms (in eV) and wavelengths of spectral lines. Complete Grotrian diagrams are given if possible, which clearly explain the transitions belonging to a given multiplet. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

ON THE LONG TIME SPECTRAL VARIABILITY OF NGC 5548

We have investigated the long term variability of the intensities of the broad-line region emission lines in the UV spectra of Seyfert I galaxy NGC 5548 from 1973–1996. We have obtained the following results: 1) a high level correlation between the intensities of emission lines as well as between intensities of emission lines and continuum fluxes was discovered. With increasing wavelength the correlation in both cases becomes weaker, 2) the relationship between the intensity of emission lines and the flux radiation in the continuum can be expressed by a power law function with coefficients of α ≈ 0.8 − 1.1 for different lines. When the difference between the wavelengths of spectral lines and the continuum is increased, the value of the power function decreases, and 3) it was found that the magnitude of the variability of the line intensities are weaker than the range of variability of the continuum fluxes. The magnitude of the variability of the line intensities and the continuum fluxes increase at longer wavelengths.

Hydrogen Balmer series measurements and determination of Rydberg's constant using two different spectrometers

This paper investigates the use of two different methods, the optical and the computer-aided diffraction-grating spectrometer, to measure the wavelength of visible lines of Balmer series from the hydrogen atomic spectrum and estimate the value of Rydberg's constant. Analysis and interpretation of data showed that both methods, despite their difference in terms of the type of equipment used, displayed good performance in terms of precision of measurements of wavelengths of spectral lines. A comparison was carried out between the experimental value of Rydberg's constant obtained with both methods and the accepted value. The results of Rydberg's constant obtained with both the optical and computer-aided spectrometers were 1.099 28 × 10−7 m−1 and 1.095 13 × 10−7 m−1 with an error difference of 0.17% and 0.20% compared to the accepted value 1.097 373 × 10−7 m−1, respectively.

주거용 15W COB LED 다운라이트 방열판 최적설계에 따른 열적 특성 분석 및 평가

There are increasing interests in COB (Chip On Board) that densely arranged many LED chips on one board in order to solve the heat issue. There are many problems being on the rise: the lifespan decreases as the temperature of LED devices increases; Red Shift phenomenon, in which wave length of spectral line moves from original wave length to long wave length, occurs; and optical power decreases as  increases. In order to resolve such problems, this study selected the optimum thickness and length of Fin, planned the second Heat sink that is optimum for COB LED with 15W, and analyzed thermal mode by Solid Works Flow Simulation through 15W COB packaging with the planned Heat sink. 15W COB down-light Heat sink that is produced based on this analysis was utilized to analyze thermal mode through contact thermometer and electrical properties through Kelthley 2430.

Recent progress in spectroscopy of tungsten1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

This contribution reviews experimental and theoretical work on spectroscopy of tungsten published since the last critical compilation of the energy levels and spectral lines of highly ionized tungsten (Kramida and Shirai. At. Data Nucl. Data Tables, 95, 305 (2009)). Since then, 18 new experimental studies were published, which resulted in new identifications and (or) significantly improved wavelengths of spectral lines and energy levels of Li-like through As-like and Pm-like tungsten. A few tens of theoretical studies of tungsten spectra were published since 2008. A number of them report on high-precision calculations of energy levels, transition wavelengths, and radiative rates for tungsten spectra, such as neutral tungsten, Yb-like, Rh-like through Rb-like, Ag-like, Ga-like, Zn-like, Ni-like, Ca-like, Al-like, Mg-like, Na-like, Ne-like, B-like, Be-like, and Li-like. These developments are reviewed. Based on new experimental data, systematic errors are removed from some of the earlier measurements. Some new data are obtained by analyzing publications of other authors. Based on new published theoretical data, some old experimental results were confirmed and assessed. Revised and extended tables of energy levels and spectral lines of highly ionized tungsten are presented.

Theoretical study of polarization atmosphere Michelsoninterferometer using multi-wavelength

The basic principle of measuring the upper atmosphere using the polarization atmosphere Michelson interferometer (PAMI) is briefly described. The relationships between the intensity and the visibility of the PAMI and the Delayed phase of the wave plate are presented. The visibility and the intensity of the PAMI are dependent on the wavelength of spectral line, showing that the 732nm line is inapplicable for measuring spectral line if the PAMI is designed specifically for the 630 nm line. The research provides a theoretical basis and practical guidance both for the theoretical study of polarization atmosphere Michelson interferometer and for the design and development of the new polarization atmosphere Michelson interferometer.

Wavelengths and Intensities of Spectral Lines in the 171–211 and 245–291 Å Ranges from Five Solar Regions Recorded by the Extreme‐Ultraviolet Imaging Spectrometer (EIS) onHinode

We present spectral line wavelengths, identifications, and intensities in the 171-211 and 245-291 A ranges from five solar plasma regions recorded by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on Hinode. The recorded data were emitted from a quiet region, two active areas on the solar disk, a limb region, and a region 20'' above the limb. The line list contains 500 lines of which 55% were identified with previously known transitions. Although the EIS spectral coverage is limited to two ranges approximately 40 A wide, the identified lines belong to a total of 56 ions from 15 elements.

The Temperature and Density Structure of an Active Region Observed with the Extreme-Ultraviolet Imaging Spectrometer on Hinode

Abstract The Extreme-Ultraviolet Imaging Spectrometer (EIS) on Hinode produces high resolution spectra that can be combined via rasters into monochromatic images of solar structures, such as active regions. Electron temperature and density maps of the structures can be obtained by imaging the structures in different spectral lines with ratios sensitive to either temperature or density. Doppler maps and ion temperature maps can be made from spectral line wavelengths and profiles, respectively. In this paper we discuss coronal temperature and density distributions within an active region, illustrating the power of EIS for solar plasma diagnostics.

On a possible variation of the proton-to-electron mass ratio: H 2 spectra in the line of sight of high-redshift quasars and in the laboratory

Recently the finding of an indication for a decrease of the proton-to-electron mass ratio μ = m p/ m e by 0.002% in the past 12 billion years was reported in the form of a Letter [E. Reinhold, R. Buning, U. Hollenstein, P. Petitjean, A. Ivanchik, W. Ubachs, Phys. Rev. Lett. 96 (2006) 151101]. Here we will further detail the methods that led to that result and put it in perspective. Laser spectroscopy on molecular hydrogen, using a narrow-band and tunable extreme ultraviolet laser system at the Laser Centre Vrije Universiteit Amsterdam, results in transition wavelengths of spectral lines in the B 1 Σ u + - X 1 Σ g + Lyman and C 1 Π u - X 1 Σ g + Werner band systems at an accuracy of (4–11) × 10 −8, depending on the wavelength region. This corresponds to an absolute accuracy of 0.000004–0.000010 nm. A database of 233 accurately calibrated H 2 lines is presented here for future reference and comparison with astronomical observations. Recent observations of the same spectroscopic features in cold hydrogen clouds at redshifts z = 2.5947325 and z = 3.0248970 in the line of sight of two quasar light sources (Q 0405−443 and Q 0347−383) resulted in 76 reliably determined transition wavelengths of H 2 lines at accuracies in the range 2 × 10 −7 to 1 × 10 −6. Those observations were performed with the Ultraviolet and Visible Echelle Spectrograph at the Very Large Telescope of the European Southern Observatory at Paranal, Chile. A third ingredient in the analysis is the calculation of an improved set of sensitivity coefficients K i , a parameter associated with each spectral line, representing the dependence of the transition wavelength on a possible variation of the proton-to-electron mass ratio μ. The new model for calculation of the K i sensitivity coefficients is based on a Dunham representation of ground state and excited state level energies, derived from the most accurate data available in literature for the X 1 Σ g + ground electronic state and the presently determined level energies in the B 1 Σ u + and C 1Π u states. Moreover, the model includes adiabatic corrections to electronic energies as well as local perturbation effects between B and C levels. The full analysis and a tabulation of the resulting K i coefficients is given in this paper. A statistical analysis of the data yields an indication for a variation of the proton-to-electron mass ratio of Δ μ/ μ = (2.45 ± 0.59) × 10 −5 for a weighted fit and Δ μ/ μ = (1.99 ± 0.58) × 10 −5 for an unweighted fit. This result, indicating the decrease of μ, has a statistical significance of 3.5 σ. Mass-variations as discussed relate to inertial or kinematic masses, rather than gravitational masses. Separate treatment of the data gives a similar positive result for each of the quasars Q 0405−443 and Q 0347−383. The statistical analysis is further documented and possible systematic shifts underlying the data, with the possibility of mimicking a non-zero Δ μ/ μ value, are discussed. The observed decrease in μ corresponds to a rate of change of d ln μ/d t = −2 × 10 −15 per year, if a linear variation with time is assumed. Experiments for detecting a possible variation of μ in the modern epoch via ultra-precision experiments on H 2 quadrupole transitions are proposed.

New Rest Wavelength Determinations for Seven Mid‐Infrared Fine‐Structure Lines by ISO ‐SWS

Observations of the planetary nebulae NGC 6302, NGC 6543, and NGC 7027 by the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO) have been used to determine rest wavelengths of spectral lines. We report on improved accuracies for wavelengths of seven mid-infrared ionic fine-structure lines.

Precision measurements of the wavelengths of spectral lines of multiply charged krypton and argon ions formed in a gas target heated by laser radiation

The first precision (with an error of 0.4–1.6 mÅ) measurements were made of the wavelengths of x-ray spectral lines emitted as a result of n=4 — n'=2 transitions in the Ne- and Na-like Kr XXVII and Kr XXVI ions. The spectra were recorded by means of a spectrograph with a spherically bent mica crystal, characterised by a spectral resolution λ/Δλ ≈ 5 × 103. The dispersion characteristic of this crystal was determined with the aid of reference lines, which were emitted by the He-like Ar XVII ion. The wavelengths of a series of dielectronic satellites of the resonance line of the Ar XVII ion were identified and measured. The results obtained were compared with calculated data.