Ionic Lines Research Articles

Micro-gas column assisted laser induced breakdown spectroscopy (MGC-LIBS): A metal elements detection method for bulk water in-situ analysis

This manuscript introduces a newly developed method for in situ analysis of bulk water samples, called micro-gas column assisted LIBS (MGC-LIBS). A specially designed MGC assistance system was employed to generate a 1.28 mm diameter stable micro-gas column in situ underwater and laser pulses were focused on the gas-liquid interface of the column to improve LIBS spectral signal of metal elements in water sample. The detection experiments on metal elements in the solution showed that the intensity of ion line in the signal was enhanced by up to 14 times, and the signal RSD value was less than 1%. The detection limits (LOD) of Mg, Ca, Sr, Na, K and Li were all less than 1 mg/L. Compared with the results obtained by direct breakdown experiments in bulk water, the LODs of MGC-LIBS were significantly improved, in which the LOD of Mg element could be reduced by nearly 7.6 times. The concentration calibration curves of the above 6 elements were obtained in the possible concentration ranges of seawater samples, and quantitative inversion experiments were carried out. The results show that the estimated value using MGC-LIBS was basically consistent with the actual value, and the minimum error was 0.12%. This method is expected to be developed into an in situ, online, real-time and highly sensitive detection method for marine investigation or natural water environment monitoring.

Descents in High-Frequency Enhanced Plasma and Ion Lines During Ionospheric Heating at Eiscat

Descents in High-Frequency Enhanced Plasma and Ion Lines During Ionospheric Heating at Eiscat

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.

Energy Levels, Wavelengths, Probabilities, and Oscillator Strengths of Transition for Ge-Like Pd, Ag, and Cd Ions

High-accuracy calculations of energy levels, wavelengths, probabilities, and oscillator strengths of transition of resonance lines for Ge-like Pd, Ag, and Cd ions have been performed. For the accurate treatment of relativity, the contributions of Breit interactions and quantum electrodynamics correction were considered. The calculated values of energy levels and wavelengths, including core–valence corrections, are found to be in excellent agreement with other theoretical and experimental values for Ge-like Pd, Ag, and Cd ions. The number of energy levels and wavelengths we considered is larger than that of any other theoretical calculations. The transition probabilities are also given where no other theoretical results and experimental values are available.

Comparison of matrix effects on atomic emission spectrometers with nitrogen microwave induced plasma

The creation and implementation of new sources of sample excitation and spectrometers based on them into the practice of analytical laboratories raises many questions for researchers about the obtained analytical characteristics of new equipment and analysis methods. The most important characteristics of any method include detection limits, accuracy and reproducibility of the results obtained. Matrix elements can have a significant effect on these parameters. The paper shows a comparison of the change in the intensities of analytical lines of elements in the presence of matrix elements with ionization potentials of 5.13 - 10.48 eV (Na, Cu, Pb, Cd, Zn, In, Ga, Bi) in the concentration range of 0 - 1 wt %. on commercially available atomic emission spectrometers with microwave plasma Grand-MP ("VMK-Optoelektronika") and Agilent MP-AES 4100 (Agilent Technologies). It is shown that the magnitude of the matrix effect in these excitation sources depends on the ionization potential of the matrix element and the total energy of the analyte line. A significant effect of matrix elements with a concentration of up to 1% wt. on the intensity of spectral lines of atoms and ions of the sample. Elements with medium and high ionization energies practically do not affect the intensity of atomic spectral lines of impurity elements and lead to a decrease in the intensity of ionic lines. The influence of easily ionized elements is more pronounced - both depressing and amplifying effects are observed, probably caused by both a change in the concentration of electrons in the plasma, leading to a linear change in the equilibrium between atoms and ions, and a decrease in the plasma temperature. An increase in the power supplied to the plasma on the Grand-MP spectrometer leads to a decrease in the effect of easily ionized elements on the intensity of the spectral lines of the elements. It is shown that the plasma in the Grand-MP spectrometer has better resistance to matrix influences as compared to the Agilent MP-AES 4100, which is associated with a large plasma volume and a higher input power.

Mid-IR cosmological spectrophotometric surveys from space: Measuring AGN and star formation at the cosmic noon with a SPICA-like mission

AbstractWe use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1–$15\, \rm{deg^2}$) with a mid-IR imaging spectrometer (17–$36\, \rm{\rm{\upmu m}}$) in conjunction with deep$70\, \rm{\rm{\upmu m}}$photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three-dimensional (3D, i.e.x,y, and redshiftz) view of galaxy evolution back to an age of the universe of less than$\sim$2 Gyrs, in the mid-IR rest frame. This survey strategy will produce a full census of the Star Formation Rate (SFR) in the universe, using polycyclic aromatic hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to$z \sim 3.5$. Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, across the full IR spectral range (17–$210\, \rm{\rm{\upmu m}}$), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionisation fine-structure lines, and SFR, from PAH and low- to mid-ionisation lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during theactivity peakat the cosmic noon ($z \sim 1$–3), through IR emission lines and features that are insensitive to the dust obscuration.

Спектроскопия барьерного разряда низкого давления. Послесвечение с ионами Ne-=SUP=-2+-=/SUP=-, Ne-=SUP=-+-=/SUP=- и Ne-=SUP=-2+-=/SUP=-

We present the results of modeling the radiation of a decaying plasma, formed by the processes of electron-ion recombination with the participation of three neon ions: the molecular ion Ne2+ and atomic ions Ne+ and Ne2+. Such a combination of ions, simultaneously participating in the formation of the plasma spectrum, was first discovered in the afterglow of a pulsed barrier discharge of a cylindrical geometry at neon pressures less than 1 Torr and an electron density[e] ≤ 4 × 1010 cm-3. The main attention is paid to the comparative analysis of the mechanisms of impact-radiation recombination of Ne+ and Ne2+ ions based on the numerical solution of the system of differential equations for the densities of ions and long-lived excited atoms in the afterglow, taking into account the main elementary processes in decaying plasma with pulsed "heating" of electrons. The regularities of electron temperature relaxation from discharge values of several electron volts to 300 K in the late afterglow are considered in particular details. Comparison of the model solutions with the spectral intensities measured by the multichannel photon counting method shows that, given their good agreement in the case of singly charged ions, an adequate description of the evolution of ionic lines requires expanding the available information on the recombination of Ne2+ ions.

Computational Simulation of Ionization Processes in Single-Bubble and Multi-Bubble Sonoluminescence

The most recent spectroscopic studies of moving-single bubble sonoluminescence (MSBSL) and multi-bubble sonoluminescence (MBSL) have revealed that hydrated electrons (e aq − ) are generated in MSBSL but absent in MBSL. To explore the mechanism this phenomenon, we numerically simulated the ionization processes in single- and multi-bubble sonoluminescence in aqueous solution of terbium chloride (TbCl3). The results show that the maximum degree of ionization of single-bubble sonoluminescence (SBSL) is approximately 10000 times greater than that of MBSL under certain special physical parameters. The hydrated electrons (e aq − ) formed in SBSL are far greater than those in MBSL provided these electrons are ejected from a bubble into a liquid. Therefore, the quenching of e aq − to SBSL spectrum is stronger than that of the MBSL spectrum. This may be the reason that the trivalent terbium [Tb(III)] ion line intensities from SBSL in the TbCl 3 aqueous solutions with the acceptor of e aq − are stronger than those of TbCl3 aqueous solutions without the acceptor of e aq − , whereas the Tb(III) ion line intensities from MBSL are not variational.

Эмиссионные спектры легких инертных газов Ne и Ar в диапазоне 3-20 nm при импульсном лазерном возбуждении с использованием различных газовых струй в качестве мишеней

The article considers the results of studies of the emission spectra of Ne and Ar upon excitation by pulsed laser radiation. We used Nd: YAG laser, λ = 1064 nm, τ = 5 ns, and Epulse = 0.8 J. The spectral range of 3-20 nm was studied. We used capillary and supersonic conical nozzles with dcr = 145 μm, 2α = 12o, L = 5 mm, and dcr = 450 μm, 2α = 11o, L = 5 mm to form an atomic cluster beam. The emission spectra for various gas targets were obtained, the obtained spectra were deciphered, and the ions emitting in this spectral range were determined. We observed that with increasing particle concentration in the zone of laser spark, the radiation intensity increases. In this case, the intensity of ion lines with high degrees of ionization increases faster.

Эмиссионные спектры тяжелых инертных газов Kr, Xe в диапазоне 3-20 nm при импульсном лазерном возбуждении с использованием различных газовых струй в качестве мишеней

The article considers the results of studies of the emission spectra of Kr, Xe upon excitation by pulsed laser radiation. We used Nd: YAG laser, λ = 1064 nm, τ = 5 ns, and Epulse = 0.8 J. The spectral range of 30-200A was studied. We used capillary with d = 500 μm and supersonic conical nozzles with dcr = 145 μm, 2α = 12o, L = 5 mm, and dcrit = 450 μm, 2α = 11o, L = 5 mm to form a gas jet. The emission spectra for various gas targets were obtained, the obtained spectra were deciphered, and the ions emitting in this spectral range were determined. We observed that with increasing particle concentration in the zone of laser spark, the radiation intensity increases. In this case, the intensity of ion lines with high degrees of ionization increases faster.

Эмиссионные спектры молекулярных газов N-=SUB=-2-=/SUB=- и CO-=SUB=-2-=/SUB=- в диапазоне 3-20 nm при импульсном лазерном возбуждении с использованием различных газовых струй в качестве мишеней

The article considers the results of studies of the emission spectra of N2 and CO2 upon excitation by pulsed laser radiation. We used Nd: YAG laser, λ = 1064 nm, τ = 5 ns, and Epulse = 0.8 J. The spectral range of 3-20 nm was studied. We used capillary and supersonic conical nozzles with dcr = 145 μm, 2α = 12o, L = 5 mm, and dcr = 450 μm, 2α = 11o, L = 5 mm to form an atomic cluster beam. The emission spectra for various gas targets were obtained, the obtained spectra were deciphered, and the ions emitting in this spectral range were determined. We observed that with increasing particle concentration in the zone of laser spark, the radiation intensity increases. In this case, the intensity of ion lines with high degrees of ionization increases faster.

Computer-assisted beam modeling for particle therapy.

PurposeTo develop a computer‐driven and thus less user‐dependent method, allowing for a simple and straightforward generation of a Monte Carlo (MC) beam model of a scanned proton and carbon ion beam delivery system.MethodsIn a first step, experimental measurements were performed for proton and carbon ion energies in the available energy ranges. Data included depth dose profiles measured in water and spot sizes in air at various isocenter distances. Using an automated regularization‐based optimization process (AUTO‐BEAM), GATE/Geant4 beam models of the respective beam lines were generated. These were obtained sequentially by using least square weighting functions with and without regularization, to iteratively tune the beam parameters energy, energy spread, beam sigma, divergence, and emittance until a user‐defined agreement was reached. Based on the parameter tuning for a set of energies, a beam model was semi‐automatically generated. The resulting beam models were validated for all centers comparing to independent measurements of laterally integrated depth dose curves and spot sizes in air. For one representative center, three‐dimensional dose cubes were measured and compared to simulations. The method was applied on one research as well as four different clinical beam lines for proton and carbon ions of three different particle therapy centers using synchrotron or cyclotron accelerator systems: (a) MedAustron ion therapy center, (b) University Proton Therapy Dresden, and (c) Center Antoine Lacassagne Nice.ResultsParticle beam ranges in the MC beam models agreed on average within 0.2 mm compared to measurements for all energies and beam lines. Spot sizes in air (full‐width at half maximum) at all positions differed by less than 0.4% from the measurements. Dose calculation with the beam model for the clinical beam line at MedAustron agreed better than 1.7% in absolute dose for a representative clinical case treated with protons. For protons, beam model generation, including geometry creation, data conversion, and validation, was possible within three working days. The number of iterations required for the optimization process to converge, was found to be similar for all beam line geometries and particle types.ConclusionThe presented method was demonstrated to work independently of the beam optics behavior of the different beam lines, particle types, and geometries. Furthermore, it is suitable for non‐expert users and requires only limited user interaction. Beam model validation for different beam lines based on different beam delivery systems, showed good agreement.

Examination of the effect of air atmosphere on heterogeneous reactions under surface ionization of psychotropic drug molecules.

The results of mass spectrometric studies of surface ionization of molecules of psychotropic drugs such as chlorpromazine, amitriptyline and medazepam in an air atmosphere have been presented. The channels of heterogeneous reactions occurring during the molecule adsorption on the hot surface of the thermoemitter from refractory metal oxides have been revealed, as well as the influence of air atmosphere on these reactions. A strong influence of the air atmosphere on the heterogeneous association reactions with the emission of [M + H]+ ions has been found. This ion line is the main in the mass spectra of all the substances under study instead of the characteristic main line in the surface ionization mass spectra obtained in vacuum. The effect of air on the reactions of dehydrogenation and dissociation of adsorbed molecules of organic compounds has been insignificant. In the surface ionization mass spectra of all the substances studied under atmospheric conditions the adduct cluster ions М⋅[М-R]+, М⋅[М-Н]+ and М⋅[М+Н]+ (where М is the molecule, R is the radical, H is the hydrogen atom) up to М⋅[М+Н]+⋅HCl. They are probably formed by adhesion of analyte molecules to the primary ions [М-R]+, [М-Н]+ and [М+Н]+. A comparative analysis has been also performed with the data obtained by chromato-mass spectrometry with electron ionization, as well as with the surface ionization data for these preparations obtained under high vacuum.

ELECTRON DENSITY SPECTROSCOPIC MEASUREMENT IN AL LASER INDUCED PLASMA

Plasma generated by a 1064 nm pulsed Nd: YAG laser with pulse duration of 10 ns concentrated onto an Al solid target under vacuum pressure was examined spectroscopically. The temperature and electron density specifying the plasma were measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time period range of 300–2000 ns. An echelle spectrograph is utilized to appear the plasma emission lines. The temperature was obtained using the spectral line comparison method and the electron density was calculated using the Stark Broadening (SB) method. The electron density was characterized as a function of laser pulse energy. The time range where the plasma is optically thin and is also in local thermodynamic equilibrium (LTE), significant for the laser-produced plasma (LPP) which was evaluated from the temporal profile of the intensity ratio of two Al I lines (λ1=380.581nm, 398.014nm, and 393.1996nm), (λ2= 586.781nm). It is found to be 700–1000 ns.

Role of the triplet metastable levels in ionization/excitation of palladium atom in glow discharge plasmas using several plasma gases

The major excitation mechanism of palladium ionic lines (Pd II) in glow discharge plasma was investigated when argon, neon, krypton, and argon‑helium mixed gas were employed as the plasma gas. Different types of Pd II lines were intensively excited depending on the kind of the plasma gases. Correspondences in the excitation energy were found for each plasma gas, the excited levels of 8.1–8.6 eV for argon, 13.1–14.4 eV for neon, and more than 15 eV for helium, while no intense Pd II lines were found in krypton. These phenomena are principally attributed to an asymmetric charge transfer collision with the plasma gas ion, as previous studies have pointed out for other metallic elements. However, the excitation scheme of the Pd II lines is somewhat different from the normal scheme for the other metallic elements. In particular, it is a unique feature that the triplet metastable levels, 4d95s 3D3,2,1, rather than the ground state level, 4d10 1S0, of the palladium atom play a critical role in excitations of the Pd II lines. This effect is principally because the total excitation energy follows the energy resonance condition, as well as the spin multiplicity follows the spin conservation rule between the colliding partners.

The Coulomb Symmetry and a Universal Representation of Rydberg Spectral Line Shapes in Magnetized Plasmas

A new method of line shape calculations of hydrogen-like atoms in magnetized plasmas is presented. This algorithm makes it possible to solve two fundamental problems in the broadening theory: the analytical description of the radiation transition array between excited atomic states and an account of a thermal ion motion effect on the line shapes formation. The solution to the first problem is based on the semiclassical approach to dipole matrix elements calculations and the usage of the specific symmetry properties of the Coulomb field. The second one is considered in terms of the kinetic treatment of the frequency fluctuation model (FFM). As the result, one has a universal description of line shapes under the action of the dynamic of ion’s microfield. The final line shape is obtained by the convolution of the ionic line shape with the Voigt electron Doppler profile. The method is applicable formally for large values of principal quantum numbers. However, the efficiency of the results is demonstrated even for well known first members of the hydrogen Balmer series Dα and Dβ lines. The comparison of obtained results with accurate quantum calculations is presented. The new method may be of interest for investigations of spectral line shapes of hydrogen-like ions presented in different kinds of hot ionized environments with the presence of a magnetic field, including So L and divertor tokamak plasmas.

Electron population properties with different energies in a helicon plasma source

The characteristics of electrons play a dominant role in determining the ionization and acceleration processes of plasmas. Compared with electrostatic diagnostics, the optical method is independent of the radio frequency (RF) noise, magnetic field, and electric field. In this paper, an optical emission spectroscope was used to determine the plasma emission spectra, electron excitation energy population distributions (EEEPDs), growth rates of low-energy and high-energy electrons, and their intensity jumps with input powers. The 56 emission lines with the highest signal-to-noise ratio and their corresponding electron excitation energy were used for the translation of the spectrum into EEEPD. One discrete EEEPD has two clear different regions, namely the low-energy electron excitation region (neutral lines with threshold energy of 13–15 eV) and the high-energy electron excitation region (ionic lines with threshold energy ≥19 eV). The EEEPD variations with different diameters of discharge tubes (20 mm, 40 mm, and 60 mm) and different input RF powers (200–1800 W) were investigated. By normalized intensity comparison of the ionic and neutral lines, the growth rate of the ionic population was higher than the neutral one, especially when the tube diameter was less than 40 mm and the input power was higher than 1000 W. Moreover, we found that the intensities of low-energy electrons and high-energy electrons jump at different input powers from inductively coupled (H) mode to helicon (W) mode; therefore, the determination of W mode needs to be carefully considered.

Plasma environment effects on K lines of astrophysical interest

Aims.Within the framework of compact-object accretion disks, we calculate plasma environment effects on the atomic structure and decay parameters used in the modeling of K lines in lowly charged iron ions, namely Fe II–Fe VIII.Methods.For this study, we used the fully relativistic multiconfiguration Dirac–Fock method approximating the plasma electron–nucleus and electron-electron screenings with a time-averaged Debye-Hückel potential.Results.We report modified ionization potentials, K-threshold energies, wavelengths, radiative emission rates, and Auger widths for plasmas characterized by electron temperatures and densities in the ranges 105 − 107K and 1018 − 1022cm−3. In addition, we propose two universal fitting formulae to predict the IP and K-threshold lowerings in any elemental ion.Conclusions.We conclude that the high-resolution X-ray spectrometers onboard the future XRISM and ATHENA space missions will be able to detect the lowering of the K edges of these Fe ions due to the extreme plasma conditions occurring in the accretion disks around compact objects.

Spatially and Temporally Resolved Two‐Dimensional Emission Images of Copper Atomic and Ionic Lines in Laser‐Induced Plasma Optical Emission Spectrometry

AbstractThis study features a two‐dimensional spatially and temporally resolved imaging of laser‐induced plasma in copper emission lines, in order to clarify the fundamental mechanism for their excitation/de‐excitations in laser‐induced breakdown spectrometry (LIBS). It was investigated how the plasma excitation was dependent on the type of copper emission lines, different atomic and ionic lines (Cu II 224.700 nm, Cu I 324.754 nm), with the aim to monitor their emission images. A large difference between these emission lines was found in the shape as well as the temporal variation of the emission profiles: while the profile of the Cu II line rapidly disappeared with an expansion of the plasma, that of the Cu I was still observed even at a final stage of the plasma expansion. This result can be explained by their excitation mechanisms. Namely, the excited level for the Cu II line having large excitation energy is mainly populated through a direct collision with an energetic particle, whereas step‐wise de‐excitations from high‐lying excited levels also contribute to the emission of the Cu I line. This result could prove to be useful in the understanding of the background of LIBS.

An Investigation of Laser Produced Lead-Tin Alloy Plasmas between 10 and 18 nm

The results of a systematic study performed on Pb-Sn alloys of concentration 65–35% and 94–6% by weight along with spectra from pure Pb and Sn in the wavelength range of 9.8–18 nm are presented. The dynamics of the Nd:YAG laser produced plasma were changed by varying the focused spot size and input energy of the laser pulse; the laser irradiance at the target varied from 7.3 × 109 W cm−2 to 1.2 × 1012 W cm−2. The contributing ion stages and line emission are identified using the steady state collisional radiative model of Colombant and Tonon, and the Cowan suite of atomic structure codes. The Sn spectrum was dominated in each case by the well-known unresolved transition array (UTA) near 13.5 nm. However, a surprising result was the lack of any enhancement or narrowing of this feature at low concentrations of Sn in the alloy spectra whose emission was essentially dominated by Pb ions.