On the Stark broadening in the Au I and Au II spectra from a helium plasma

The Stark FWHM (Full-Width at Half of the Maximal line intensity, W) of 5 neutral and 26 singly ionized gold (Au I and Au II, respectively) spectral lines have been measured in laboratory helium plasma at approximately 16,600 K electron temperature and 7.4 × 10²² m^− 3 electron density. Five Au I and ten Au II W values are reported for the first time. The Au II W values are compared with recent theoretical data, calculated based on a modified semi-empirical approach, and also with existing experimental W values. Our normalized Stark widths are six times higher than those measured in a laser-produced plasma. Possible explanation of this is recommended here. An agreement (within the accuracy of the experiment and uncertainties of the theoretical approach used) with the recently calculated W data was found in the 6p–7s Au II transition. The calculated hyperfine splitting for the five Au II lines in the 6s–6p transition is also presented. At the stated helium plasma conditions, Stark broadening has been found to be the dominant mechanism in the Au I and Au II line shape formation. A modified version of the linear low-pressure pulsed arc was used as a plasma source operated in helium, with gold atoms as impurities evaporated from the thin gold cylindrical plates located in the homogeneous part of the discharge, providing conditions free of self-absorption. This plasma source ensures good conditions for generation of excited gold ions due to Penning and charge exchange effects.     

The first measurement of the In III Stark widths

The shapes of 16 doubly ionized indium (In III) spectral lines have been measured in the laboratory helium plasma at 13,000 K electron temperature and 1.48 × 10²³ m^− 3 electron density. At mentioned plasma conditions the Stark broadening has been found as the dominant mechanism in the line shape formation. Here presented data are the first reported values for Stark widths (W) related to the specific In III lines. The modified version of the linear, low-pressure, pulsed arc was used as a plasma source operated in helium with indium atoms, as impurities, evaporated from indium cylindrical plates located in the homogenous part of the discharge, providing conditions free of self-absorption. At the above mentioned helium plasma conditions we have found symmetrical In III line profiles of the Voigt type. This means that the expected hyperfine structure splitting (Δ_hfs) in the investigated In III lines has been overpowered by Stark and Doppler broadening. We recommend the found W values of the intense and well isolated 298.280, 403.232 and 524.877 nm In III lines for the plasma electron density diagnostic ranged between 10²¹ m^− 3 and 10²³ m^− 3.     

Stark broadening and regularities of ionized neon and argon spectral lines

Stark widths of five Ne III, five Ne IV, one Ar III and nine ArIV spectral lines have been measured in a linear-pinch discharge plasma. The results were compared with existing experimental and theoretical results, and used to establish several types of regularities. Electron densities determined with single-wavelength laser interferometry were 2.18·10²³ m^?3 and 2.80·10²³ m^?3 in neon and argon plasma, respectively. The electron temperatures determined from the Boltzmann slope of several Ne III spectral lines, and ratios of Ne III to Ne IV or Ar III to Ar IV spectral lines were 59 000 K and 42 000 K in neon and argon plasma, respectively. The investigated spectral lines originate predominantly, from 3s–3p and 3s′–3p′ Ne III and Ne IV, and from 4s–4p and 4s′–4p′ Ar III and Ar IV transition arrays. The emphasis is on the Stark width (θ) dependence on the upper level ionization potential (I), the emitter core net charge (z) and electron temperature (T) for a given electron density. This dependence was found to be of the form: θ=az ² T ^?1/2 I ^?b , wherea andb are constants within(i) several stages of ionization of neon or argon and(ii) within nitrogen like (NI, O II, F III and Ne IV) 3s–3p or phosphorus like (P I, S II, Cl III and Ar IV) 4s–4p transition arrays. The established overall trends were used to predict the Stark widths of univestigated spectral lines originating from the given transition arrays.     

Measured Stark widths of several spectral lines of Pb III

The Stark full widths at half of the maximal line intensity (FWHM, ω) have been measured for 25 spectral lines of Pb III (15 measured for the first time) arising from the 5d¹⁰6s8s, 5d¹⁰6s7p, 5d¹⁰6s5f and 5d¹⁰6s5g electronic configurations, in a lead plasma produced by ablation with a Nd:YAG laser. The optical emission spectroscopy from a laser-induced plasma generated by a 10 640 Å radiation, with an irradiance of 2 × 10¹⁰ W cm^− 2 on a lead target (99.99% purity) in an atmosphere of argon was analysed in the wavelength interval between 2000 and 7000 Å. The broadening parameters were obtained with the target placed in argon atmosphere at 6 Torr and 400 ns after each laser light pulse, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma temperature (21,400 K) and published values of the Stark widths in Pb I, Pb II and Pb III to obtain the electron number density (7 × 10¹⁶ cm^− 3); with these values, the plasma composition was determined by means of the Saha equation. Local Thermodynamic Equilibrium (LTE) conditions and plasma homogeneity has been checked. Special attention was dedicated to the possible self-absorption of the different transitions. Comparison of the new results with recent available data is also presented.     

Stark width and shift of singly-ionized tin spectral lines

Stark widths and shifts of six singly-ionized tin spectral lines have been measured in a pulsed linear arc plasma in SF₆, at 33000 K electron temperature and 0.96 × 10²³ m^?3 electron density, and compared with existing experimental results.     

The first measured Ag I, Ag II and Ag III Stark broadening parameters

The Stark widths (W) and shifts (d) of two neutral (520.908 and 546.550 nm), eleven singly (211.382, 224.643, 224.874, 232.029, 232.468, 233.140, 241.141, 241.323, 243.781, 244.793 and 276.754 nm) and three doubly (216.189, 231.004 and 239.569 nm) ionized silver (Ag I, Ag II and Ag III, respectively) spectral lines have been measured in nitrogen plasma at about 18,000 K electron temperature and electron density ranged between 0.65 × 10²³ and 1.15 × 10²³ m^− 3. They are the first measured W and d values while those of the Ag II and Ag III lines are the first published data in these spectra. The modified version of the linear, low-pressure, pulsed arc was used as a plasma source operated in nitrogen with silver atoms, as impurities, evaporated from silver cylindrical plates located in the homogeneous part of the discharge. No theoretical predictions exist for W and d values of above mentioned spectral lines. Besides, we have checked the transition probability ratio of two investigated Ag I lines. An agreement with theoretical predictions was found.     

A spectroscopic study of laser-induced tin–lead plasma: Transition probabilities for spectral lines of Sn I

In this paper, we present transition probabilities for 97 spectral lines of Sn I, corresponding to transitions n(n = 6,7,8)s → 5p², n(n = 5,6,7)d → 5p², 5p³ → 5p², n(n = 7)p → 6s, determined by measuring the intensities of the emission lines of a Laser-induced breakdown (emission) spectrometry (LIBS). The optical emission spectroscopy from a laser-induced plasma generated by a 10 640 Å radiation, with an irradiance of 1.4 × 10¹⁰ Wcm^− 2 on an Sn–Pb alloy (an Sn content of approximately 20%), in vacuum, was recorded at 0.8 µs, and analysed between 1900 and 7000 Å. The population-level distribution and corresponding temperature were obtained using Boltzmann plots. The electron density of the plasma was determined using well-known Stark broadening parameters of spectral lines. The plasma under study had an electron temperature of 13,200 K and an electron number density of 2 × 10¹⁶ cm^− 3. The experimental relative transition probabilities were put on an absolute scale using the branching ratio method to calculate Sn I multiplet transition probabilities from available radiative lifetime data of their upper states and plotting the Sn I emission spectrum lines on a Boltzmann plot assuming local thermodynamic equilibrium (LTE) to be valid and following Boltzmann's law. The LTE conditions and plasma homogeneity have been checked. Special attention was paid to the possible self-absorption of the different transitions. The experimental results obtained have been compared with the experimental values given by other authors.     

Structural investigations on diorgano- and triorganotin(IV) derivatives of [meso-tetra(4-sulfonatophenyl)porphine] metal chlorides

Several new complexes of organotin(IV) moieties with MCl_n[meso-tetra(4-sulfonatophenyl)porphine], (R₂Sn)₂MCl_n[meso-tetra(4-sulfonatophenyl)-porphinate]s and (R₃Sn)₄MCl_n [meso-tetra(4-sulfonatophenyl)porphinate]s, [M = Fe(III), Mn(III): n = 1, R = Me, n-Bu; Ph; M = Sn(IV): n = 2, R = Me, n-Bu] have been synthesized and their solid state configuration investigated by infrared (IR) and Mössbauer spectroscopy, and by ¹H and ¹³C NMR in D₂O.The electron density on the metal ion coordinated inside the porphyrin ring is not influenced by the organotin(IV) moieties bonded to the oxygen atoms of the side chain sulfonatophenyl groups, as it has been inferred on the basis of Mössbauer spectroscopy and, in particular, from the invariance of the isomer shift of the Fe(III) and Sn(IV) atoms coordinated into the porphyrin square plane of the newly synthesized complexes, with respect to the same atoms in the free ligand.As far as the coordination polyhedra around the peripheral tin atoms are concerned, infrared spectra and experimental Mössbauer data would suggest octahedral and trigonal bipyramidal environments around tin, in polymeric configurations obtained, respectively, in the diorganotin derivatives through chelating or bridging sulfonate groups coordinating in the square plane, and in triorganotin(IV) complexes through bridging sulfonate oxygen atoms in axial positions.The structures of the (Me₃Sn)₄Sn(IV)Cl₂[meso-tetra(4-sulfonatophenyl)porphinate] and of the two model systems, Me₃Sn(PS)(HPS) and Me₂Sn(PS)₂ [HPS = phenylsulfonic acid], have been studied by a two layer ONIOM method, using the hybrid DFT B3LYP functional for the higher layer, including the significant tin environment. This approach allowed us to support the structural hypotheses inferred by the IR and Mössbauer spectroscopy analysis and to obtain detailed geometrical information of the tin environment in the compounds investigated.¹H and ¹³C NMR data suggested retention of the geometry around the tin(IV) atom in D₂O solution.     

Band gap tailoring of chemically synthesized lead sulfide thin films by in situ Sn doping

In the present report, undoped and tin (Sn)‐doped lead sulfide thin films were synthesized via chemical bath deposition method. The effects of Sn molar concentration on the optical, structural, and morphological properties were systematically studied. The concentration of Sn in the chemical bath was characterized by the ratio of [Sn⁺²]/[Pb⁺²] and varied from 0 to 15 at.%. Both doped and undoped thin films were polycrystalline in nature with a face‐centered cubic crystal structure; however, the preferred orientations of the crystallites were varied along the (111) and (200) planes with Sn‐doping concentration. The X‐ray powder diffraction results also showed that peak intensities and the crystalline size were decreased with increasing Sn concentration. The lattice constant varied with Sn concentration and found in the range of 6.020 to 5.944 Å. The variation of Sn concentration in PbS:Sn thin films were confirmed by energy dispersive X‐ray analyses study. The scanning electron microscope and atomic force microscopy studies revealed that Sn doping had a critical role on the surface roughness and morphology of the PbS:Sn thin films. The optical band gap study showed that the band gap of PbS:Sn thin films were engineered from 0.676 to 1.345 eV because of incorporation of Sn⁺² ions via cost‐effective chemical route. Room temperature photoluminescence spectra showed a well‐defined peak at 427 nm and shoulders at 405 and 462 nm for all Sn‐doped and undoped PbS samples.     

Stark broadening of Mg I and Mg II spectral lines and Debye shielding effect in laser induced plasma

We report Stark broadening parameters for three Mg I lines and one Mg II line in the electron number density range (0.67–1.09) · 10¹⁷ cm^− 3 and electron temperature interval (6200–6500) K. The electron density is determined from the half width of hydrogen impurity line, the H_α, while the electron temperature is measured from relative intensities of Mg I or Al II lines using Boltzmann plot technique. The plasma source was induced by Nd:YAG laser radiation at 1.06 μm having pulse width 15 ns and pulse energy 50 mJ. Laser induced plasma is generated in front of a solid state surface. High speed photography is used to determine time of plasma decay with good homogeneity and then applied line self-absorption test and Abel inversion procedure. The details of data acquisition and data processing are described and illustrated with typical examples. The experimental results are compared with two sets of semiclassical calculations and the results of this comparison for Mg I lines are not unambiguous while for Mg II 448.1 nm line, the results of Dimitrijević and Sahal-Bréchot calculations agree well with our and other experimental results in the temperature range (5000–12,000) K and these theoretical results are recommended for plasma diagnostic purposes. The study of line shapes within Mg I 383.53 nm multiplet shows that the use of Debye shielding correction improves the agreement between theoretical and experimental Stark broadening parameters.     

Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser

Laser-induced breakdown spectroscopy of helium plasma, initially at room temperature and pressures ranging from 12 to 101 kPa was investigated using a transverse excitation atmospheric CO₂ pulsed laser (λ = 9.621 and 10.591 μm, a full width at half maximum of 64 ns, and an intensity from 1.5 to 5.36 GW cm⁻²). The helium breakdown spectrum is mainly due to electronic relaxation of excited He, He⁺ and H. Plasma characteristics were examined in detail on the emission lines of He and He⁺ by the time-integrated and time-resolved optical emission spectroscopy technique. Optical breakdown threshold intensities, ionization degree and plasma temperatures were obtained. An auxiliary metal mesh target was used to analyze the temporal evolution of the species in the plasma. The results show a faster decay of the continuum emission and He⁺ species than in the case of neutral He atoms. The velocity and kinetic energy distributions for He and He⁺ species were obtained from time-of-flight measurements. Electron density in the laser-induced plasma was estimated from the analysis of spectral data at various times from the laser pulse incidence. Temporal evolution of electron density has been used for the estimation of the three-body electron-ion recombination rate constant.     

Extraction of Ag(I), Cd(II), In(III), Sn(II), Sn(IV), Sb(III), and U(VI) from aqueous solutions by ketone solutions using single-step batch and continuous SISAK methods1,2

The extraction properties of Ag(I), Cd(II), In(III), Sn(II), Sn(IV), Sb(III), and U(VI) from aqueous KI/H₂SO₄ solution into a mixture of 4-methyl-2-pentanone (methyl isobutyl ketone, MIBK) and cyclohexanone (CHO) were studied. Both single-step batch and SISAK² methods were used. The oxidation of Sn(II) to Sn(IV) by iodine and complexation of Sn(IV) by 2,3-dimercapto-propanol-1 (BAL) were also investigated. A method for rapid and continuous separation of indium from tin was developed for investigation of short-lived indium fission products.     

Low power cross-flow atmospheric pressure Ar + He plasma jet : Spectroscopic diagnostic and excitation capabilities

A cross-flow atmospheric plasma jet with distilled water or analyte solution nebulization has been investigated. The plasma gas flows perpendicularly to the RF powered electrode (11.21 MHz) and a grounded electrode was added for plasma stabilization. The working parameters of the plasma generator can be controlled in order to maximize either the plasma power (75 W) or the voltage on the RF powered electrode (plasma power, 40 W). The plasma gas, pure argon (0.4 l min⁻¹) or a mixture of argon (0.3–0.4 l min⁻¹) and helium (0–0.2 l min⁻¹), was also used for liquid nebulization. Optical emission of the plasma, collected in the normal viewing mode, was used for plasma diagnostics and for evaluating its excitation capabilities. The influence of helium content in the mixed-gas plasma on the plasma characteristics and on the emission axial profiles of the plasma gas constituents and of the analytes originate from the wet aerosol was studied. The addition of helium to the argon plasma, generally determines decreases in the emission of the plasma gas constituents (with the exception of molecular nitrogen), in the rotational temperature and in the electron number density and increases in the excitation temperatures and in the emission of easily excitable analytes. Based on the determined electron number densities, it was concluded that in the plasma zone which presents interest from analytical point of view the plasma is not very far from the partial thermodynamic equilibrium. In function of the helium content in the plasma gas and of the axial distance from the powered electrode the excitation temperatures are in the range of 2420–3340 K for argon, 2500–5450 K for oxygen and 900–2610 K for ionic calcium and the electron number densities are in the range of 1.2 10¹²–1.25 10¹³ cm⁻³. Some elements with excitation energy lower than 6 eV were excited in the plasma. The plasma excitation capability depends on the working conditions of the plasma generator (maximum power or maximum voltage on the RF powered electrode) and on the helium content in the mixed-gas plasma. The estimated detection limits for the studied elements (Na, Li, K, Ca, Cu, Ag, Cd, Hg and Zn) are in the range of 7 ng ml⁻¹ to 28 μg ml⁻¹.     

Tin(II) Phthalocyaninate and Tin(IV) bis-Phthaloc Yaninate: A Quantum Chemical Study

The structural parameters of tin(II) phthalocyaninate PcSn and tin(IV) bis-phthalocyaninate Pc₂Sn as well as of their cations are determined by B3LYP/SDD and PBE0/SDD quantum chemical methods. The PcSn molecule is characterized by C_4v symmetry, and SnN bond lengths are 2.307/2.299 ? (B3LYP/PBE0). The Sn nucleus is by 1.11 ? (B3LYP, PBE0, single crystal X-ray diffraction analysis) higher than the plane of four neighboring nitrogen nuclei. The “hindered” configuration (D _4d symmetry) with a high (27–30 kcal/mole) internal rotation barrier corresponds to the Pc₂Sn energy minimum. The calculated equilibrium lengths of eight equivalent SnN bonds of 2.366/2.347 (B3LYP/PBE0) are similar to the average SnN bond length of 2.347 ? (single crystal X-ray diffraction). Vertical and adiabatic ionization potentials are calculated: I^v 6.40/6.48 eV, I^A 6.38/6.45 eV for PcSn and I^v 5.63/5.66 eV, I^A 5.60/5.63 eV for Pc₂Sn.     

Stark broadening and shift of OII spectral lines in higher multiplets

Stark widths and shifts of nineteen singly-ionized oxygen spectral lines, mostly of higher multiplets, have been measured in a pulsed linear arc plasma in an oxygen-nitrogen mixture at 8.1×10²² m^?3 electron density and 60000 K electron temperature. The measured widths and shifts values are compared, for eight multiplets, with existing theoretical results.     

Separation of trace elements,In(III), Sn(IV), Sb(V) and Te(IV) by adsorption on activated carbon and graphite

Adsorption behaviour of trace elements, In(III), Sn(IV), Sb(V) and Te(IV) on activated carbon and graphite powder was studied. Adsorption characteristics of the ions enabled the separation of In(III)–Sn(IV), Sn(IV)–Sb(V) and Sb(V)–Te(IV) pairs. Applications to practical separation, milking of^113mIn from¹¹³Sn, removal of tin impurity from¹¹⁹Sb, and milking of¹¹⁹Sb from^119mTe, are presented.     

Application of laser-induced plasma spectroscopy to the measurement of Stark broadening parameters

In this work, we have studied the main conditions that a laser-induced plasma must fulfill in order to be considered as adequate for the measurement of Stark broadening parameters. We investigated the effect of the temporal window, the self-absorption, the crater size, and the effect of the spatial inhomogeneity on the emission profiles coming from a laser-induced plasma. Starting from the spatially resolved values of the plasma parameters, obtained by emission spectroscopy, the error in the determination of the Stark electron width due to the spatial inhomogeneity has been estimated and, for the present experimental conditions, was found to be lower than 7%. As a test of the method, the Stark electron broadening constant of Fe I 381.58 nm has been measured using the Fe I 538.34 nm emission line as the reference to determine the electron density. The plasma was produced under a controlled atmosphere of argon at atmospheric pressure, on an iron–nickel alloy sample. The emission was collected by a system with high spectral resolution, for different temporal windows after the laser pulse. For time delays between 2.75 and 21 μs, the electron density showed an evolution in the range 2.0–0.13 × 10¹⁷ cm^− 3, while the temperature varied from 11 100 to 7100 K. The representation of the Stark electron width of Fe I 381.58 nm, measured for each temporal window, versus the Stark electron width of the reference line showed a linear behavior with a high correlation coefficient. From the slope of this linear fit and the Stark electron broadening constant of the reference line, the Stark width of Fe I 381.58 nm was obtained to be 1.10 ± 0.07 × 10^− 2 nm for an electron density of 10¹⁷ cm^− 3.     

Synthesis and characteristic studies of tin(II) and tin(IV) complexes of macrocyclic schiff bases

Equimolar reactions of tin (II) chloride, tin(IV) chloride or dimethyltin dichloride with macrocyclic Schiff bases lead to the formation of a new series of tin(II) and tin(IV) complexes. An attempt has been made to prove the structures of the resulting complexes on the basis of elemental analysis, conductance measurements, molecular-weight determination, and electronic, IR and multinuclear magnetic resonance (¹H, ¹³C and ¹¹⁹Sn) spectral studies.     

Optical emission spectrometric determination of arsenic and antimony by continuous flow chemical hydride generation and a miniaturized microwave microstrip argon plasma operated inside a capillary channel in a sapphire wafer

Continuous flow chemical hydride generation coupled directly to a 40 W, atmospheric pressure, 2.45 GHz microwave microstrip Ar plasma operated inside a capillary channel in a sapphire wafer has been optimized for the emission spectrometric determination of As and Sb. The effect of the NaBH₄ concentration, the concentration of HCl, HNO₃ and H₂SO₄ used for sample acidification, the Ar flow rate, the reagent flow rates, the liquid volume in the separator as well as the presence of interfering metals such as Fe, Cu, Ni, Co, Zn, Cd, Mn, Pb and Cr, was investigated in detail. A considerable influence of Fe(III) (enhancement of up to 50 %) for As(V) and of Fe(III), Cu(II) and Cr(III) (suppression of up to 75%) as well as of Cd(II) and Mn(II) (suppression by up to 25%) for Sb(III) was found to occur, which did not change by more than a factor of 2 in the concentration range of 2–20 μg ml^− 1. The microstrip plasma tolerated the introduction of 4.2 ml min^− 1 of H₂ in the Ar working gas, which corresponded to an H₂/Ar ratio of 28%. Under these conditions, the excitation temperature as measured with Ar atom lines and the electron number density as determined from the Stark broadening of the H_β line was of the order of 5500 K and 1.50 · 10¹⁴ cm^− 3, respectively. Detection limits (3σ) of 18 ng ml^− 1 for As and 31 ng ml^− 1 for Sb were found and the calibration curves were linear over 2 orders of magnitude. With the procedure developed As and Sb could be determined at the 45 and 6.4 μg ml^− 1 level in a galvanic bath solution containing 2.5% of NiSO₄. Additionally, As was determined in a coal fly ash reference material (NIST SRM 1633a) with a certified concentration of As of 145 ± 15 μg g^− 1 and a value of 144 ± 4 μg g^− 1 was found.     

Stark broadening and shift of multiply ionized carbon spectral lines

Stark widths and shifts of sixCII, threeCIII and twoCIV spectral lines have been measured in a linear pinch discharge plasma and compared with available experimental and theoretical data. Electron density, (0.86?1.64)×10²³ m^?3, was determined by single wavelength laser interferometry using the visible 632.8 nm transition of He-Ne laser. The electron temperature of 38000 K was derived from the Boltzmann slope of severalCII spectral lines, and ratios of severalCII toCIII spectral lines. The stark widths (w) dependence on:(i) the upper-level ionization potential (I) of corresponding lines;(ii) net charge (z) of the emitter core seen by the optical electron undergoing transition, and(iii) electron temperature (T) was found to be of the form:w=az ² T ^?1/2 I ^?b . However, it should be noticed that the essential role in the obtained trends belongs to the energy of the emitter core. The established overall trend is used to predict Stark widths of uninvestigated spectral lines originating from the given transition arrays.