Sulfur Lines Research Articles

Red/Near-Infrared Atomic Analysis for H, C, N, O, S, Cl, and Br with a Fourier Transform Inductively Coupled Plasma Emission Spectrometer

Medium resolution (0.25 cm−1) Fourier transform atomic emission reference spectra of H, C, N, O, S, Cl, Br, and Ar are presented in the red/near-infrared (15,800–8300 cm−1) region for a “pure” argon inductively coupled plasma. A silicon photodiode detector provided the red response needed to measure atomic hydrogen emissions simultaneously with near-infrared lines of the other nonmetals. Several new ICP excited lines of sulfur and carbon are reported. A list of relative intensities for all observed lines in this region is presented, and an 84-page appendix containing labelled medium resolution plots of the entire spectral region for seven elements and the argon background is available upon request. Transparent master overlays of the appendix are also available. Phase error with single-sided interferograms is studied, and the application of standard correction methods prior to power spectrum plotting is explored for red/near-infrared atomic emissions. The interaction between spectral line intensity and resolution is studied in this region.

Experimental Stark parameters for some spectral lines in SF6 plasma

Stark widths of some sulphur and fluorine spectral lines emitted by a wall-stabilised arc have been measured in order to provide simple relations for practical diagnostics. Different mixtures of SF6, H2 and Ar were used and end-on or side-on observations were performed in order to yield information about the electronic concentration and temperature. An alternative method of electronic density diagnostics is proposed by measuring the relative dip between two close lines of the 4s 5S0-5p 5P multiplet of SI.

Measurements of electron density in a SF6 arc plasma

Several methods for electron number density (Ne) determination in a SF6 arc plasma are successively described: two-wave laser interferometry, Stark broadening of neutral sulphur lines, an original method derived from Stark broadening of a sulphur triplet, the recombination continuum and the derivation of Ne from temperature measurement. The results are in good agreement; they show the existence of departures from LTE due to a demixing effect.

The flow and deformation of synthetic polypeptide monolayers during compression

Monolayers of poly-γ-ethyl- l-glutamate and poly-ε-benzyloxycarbonyl- l-lysine have been studied at the air-water interface. Application of lines of sulfur to the monolayer shows that the collapse of the monolayer to bilayer starts in the region of the moving barrier and that this transition is then propagated along the surface. The flow patterns recorded photographically show regions of compression and elongation of the film, while expansion occurs to the rear of a Wilhelmy plate. It is possible in some cases to relate the flow patterns to the orientation of the molecules. Any obstruction to flow can seriously perturb the monolayer and produce flow and orientation effects which depend on the geometry of the system. These effects are important in relation to measurements with a Wilhelmy plate and deposition of Langmuir-Blodgett films. The results require a revision of conclusions drawn from some recent studies of nucleation and collapse in polypeptide monolayers.

Quantitation of sulphur in xylene with an inductively-coupled plasma photodiode-array spectrometer

The application of an inductively-coupled plasma spectrometer with a photodiode-array detection system to the direct quantitation of total sulphur in xylene is described. The emission lines utilized are the near-infrared atomic sulphur (S I) lines at 921.29, 922.81, and 923.75 nm. Structure in the background emission spectrum in this region is attributed to the Philips molecular C 2 band. The best spatial zone to observe is at 12 mm above the load coil. The detection limit for sulphur at the 921.29-nm line is 100 mg l −1.

The Examination of Martensite Streaks for Molybdenum Segregation

Abstract In the investigation of candidate eutectoid steels for premium rails, pearlitic and bainitic microstructures of end-quench specimens from some rolled plates contain white martensitic streaks. The number of streaks is enhanced by the presence of molybdenum, and microprobe analyses demonstrated peak molybdenum concentrations in the streaks of up to five times the average value.This finding was questioned as a possible overlap of sulphur and molybdenum X-ray lines and led to further detailed work on the initial steels and on new ones with a 0.003 % sulphur content.The results show unambiguously that the streaks are greatly enriched in molybdenum, that increases in the chromium and manganese levels also occur, although by smaller factors, and that sulphur is not detectable except in the form of an occasional sulphide. Resume En examinant des aciers eutectoides appropries pour la fabrication de rails de tres bonne qualite, on a decouvertque les microstructures perlitiques et bainitiques des echantillo...

The determination of sulphate in natural waters by inductively-coupled plasma emission spectrometry

Sulphate is determined simultaneously with other constituents by using inductively-coupled plasma emission spectrometry; the intensity of the 180.73-nm sulphur line is monitored. At a forward power of 1100 W, under compromise conditions, a 3 s detection limit of 0.08 mg l -1 sulphate and a precision of 0.8% RSD at the 200 mg l -1 sulphate level were obtained. A small spectral interference from calcium is overcome by software corrections, and good agreement is demonstrated between the proposed method and spectrophotometric sulphate measurements for a variety of natural waters including seawater.

Near Infrared Atomic Emissions of Sulfur and Carbon in the Argon Inductively Coupled Plasma

Inductively coupled plasma (ICP) excitation of the 9212.91 Å nonresonant line of atomic sulfur is reported and is found to yield a detection limit more than 20-fold better than any visible or “air path” ultraviolet sulfur lines produced by the argon ICP. The ICP excited spectrum reported here for the element sulfur is markedly different from that reported for atmospheric pressure microwave-induced helium plasmas. Partial Grotrian diagrams and tables of relative intensities, detection limits, and corresponding wavelengths of 30 ICP excited, nonresonant atomic sulfur emission lines and 20 ICP excited, nonresonant atomic carbon lines are presented for the air path, photomultiplier accessible region 2000 to 9900 Å. No lines of ionized sulfur were observed in the 27-MHz, 1.75-kW argon ICP. Vertical emission intensity profiles of near infrared S(I) and C(I) lines are presented for both conventional and extended ICP torches. The present near infrared (S(I) 9212.91 Å and C(I) 9094.83 Å) detection limits for sulfur and carbon are 0.006 μg and 0.13 μg, respectively, using 8 μL gas sampling loop injections of H2S and CH4 into a low-volume transfer line leading directly into the ICP.

The chemical composition and structure of 30 Doradus

Spectrophotometry of many regions within 30 Doradus in the Large Magellanic Cloud provides chemical abundances and densities for this nebular complex. The helium to hydrogen abundance ratio is about one-tenth by number and the heavier elements are underabundant compared to Orion, with nitrogen showing the greatest deficit. The forbidden lines of singly-ionized sulphur show wide density variations across this object. The distribution of the intensities in these sulphur lines suggests that supernova shocks may have played an important role in producing the composite appearance of this giant HII region.

Stark broadening of S(III) and S(IV) lines

Measurements of the Stark widths of doubly and triply ionized sulfur lines were made in a low pressure, pulsed arc plasma of electron density 5.1 × 10 16 cm -3 at an electron temperature of 28, 500°K. The experimental S(III) and S(IV) Stark-profile halfwidths were compared with calculated values obtained with Griem's semiempirical and approximate semiclassical approach. The experimental results agree better with the semiclassical results.

Temperature anisotropy of the Jovian sulfur nebula

We discuss the apparent paradox between the reported observation of a 3-eV gyration energy of Jupiter's ionized sulfur nebula and its observed thickness. We present an observation of the thickness of the cloud taken nearly edge on and show that this implies a large bounce-averaged anisotropy of the sulfur in temperature, T ‖ ≫ T ⊥. From these observations, we construct a self-consistent model of the sulfur nebula in which the sulfur ions are injected by Io as ions and remain sufficiently collisionless in the magnetosphere to maintain the anisotropy for a time longer than a characteristic diffusion time. We also show that the proton-electron plasma is collisionally thermalized and provides an adequate means of tapping the rotational energy of the planet to provide the power radiated in the sulfur lines.

Identification of S and S2− states from Auger line shapes

Experimental results of sulfur line shape variations observed from various metal–sulfur compounds (Cu5FeS4, Cu2S, FeS) show that Auger fine structure analysis is able to separate chemical states of sulfur. Atomic sulfur presents a single Auger line at 149 eV whereas sulfur in the S2− oxidation state is characterized by a peak at 147 eV.

Plasma atomic emission spectrometric determination of sulfur in the vacuum ultraviolet region of the spectrum

A dc discharge plasma source has been utilized for the determination of sulfur in solutions using optical atomic emission spectroscopy. The sulfur resonance lines which occur at 180.7, 182.0, and 182.6 nm were used in this work. A simple argon purge system was developed to reduce light absorption by oxygen. This excitation source, coupled with the purge system, appropriate optics, and detection equipment, enabled the determination of total sulfur in aqueous solutions with the same sensitivity for different sulfur species. A detection limit of 0.5 ppM and a linear dynamic range of 2000 ppM sulfur were attained. Several potential chemical and spectral interferences were investigated. The instrumentation was also used to determine sulfur in organic solvents and to determine Hg, Se, As, I, and P in aqueous solutions.

Measurements of S II optical emission from the thermal plasma of Jupiter

Photometric spectra of the forbidden S II emission lines at 6716 and 6731 A originating in the Jovian magnetosphere are examined. The summed apparent emission rate in the two sulfur lines is plotted against the central-meridian longitude of Jupiter in System III. It is found that the total sulfur brightness exhibited a distinct minimum when the Jovian magnetic dipole was in the plane defined by the earth-Jupiter vector and the Jovian rotational axis. The observations are shown to be qualitatively consistent with an annular emitting region at the magnetic equator with a thickness of about 1 Jupiter radius and an inner radius of 4 to 5 Jupiter radii. The observations also imply a (logarithmic) characteristic electron density of approximately 3.7 per cu cm and a (logarithmic) average column abundance of about 11.5 per sq cm for singly ionized sulfur.

Energy transfer processes in reactions of He(2 3S) with triatomic molecules. II. H 2O and H 2S

The energy transfer reactions He(2 3S) + H 2O and He(2 3S) + H 2S were studied spectroscopically in the visible and ultraviolet ranges in a flowing afterglow apparatus. No primary triatomic ion emission was observed in this study. Only dissociative fragments were found to emit. In the He(2 3S)/H 2O system intense OH(A 2Σ + → X 2Π i) emission bands and hydrogen Balmer series were observed while in the He(2 3S)/H 2S system intense HS +(A 3Π i → X 3 Σ −), weak hydrogen Balmer series and some atomic sulfur lines were found. It is concluded that dissociative processes are competitive with Penning ionization in these energy transfer reactions with other possible reaction channels playing inferior roles. The post-ionization process of ion—electron recombination in the flowing afterglow dominates the emission results in the He(2 3S)/H 2O system.

A spectroscopic study of a high-frequency, inductively-coupled ArH 2S plasma

An inductively coupled argon plasma working at atmospheric pressure and having a small amount of H 2S (0.5%) added was studied. Physical parameters such as electron density and ionization temperature were determined by measuring the Stark broadening of the Hβ line and 5495 Ar(I) line. The excitation temperature was measured from Ti and Fe injected into the plasma. These results indicate that LTE does not prevail in this kind of source. The spectrum of sulfur was studied in the 4180–6060 Å range. New and known lines of sulfur are given.

Some Characteristics of Low Pressure, Sulfur, Microwave-Excited, Electrodeless Discharge Lamps

Electrodeless discharge lamps (EDL) containing different sulfur compounds (elemental sulfur, H2S, SO2, ZnS, Na2S, and CS2) have been fabricated using quartz tubes (30 mm long by 8 mm i.d.) and He, Ar, Ne, Kr, or Xe as fill gases. Intensity and stability of EDL have been observed using fill-gas pressures ranging from 0.01 to 1.7 Torr at 216.9, 469.5, 545.4 (sulfur lines) and 384.0 nm (S2 band head). Data are presented showing the effects of temperature on the intensity and stability of the EDL. Optimal conditions for each sulfur compound and fill gas are given.

Observations of heavy-element recombination lines in the Rho Ophiuchi dark cloud at 13 centimeters wavelength

High-sensitivity observations at the carbon 140-alpha and 141-alpha recombination-line frequencies in the direction of the Rho Oph dust cloud show the presence of recombination lines of carbon and sulfur, but not of other heavy elements. These results require that the elements Si, Fe, and Mg are depleted by factors greater than 15, 10, and 2, respectively, most likely into interstellar grains, whereas sulfur is undepleted. They also require that only approximately one-sixth of the carbon is present in the gas phase in the cloud. From the observed size of the C II region together with the observed carbon depletion, it is inferred that the density in the carbon-line-emitting region is 25,000 per cu cm and that the size of the S II region is significantly larger than that of the C II region. The agreement between the widths of the recombination lines (which arise in a small region of the cloud) and those of the more widely distributed molecular species suggests that the lines in this cloud are broadened by microturbulence on a scale of much less than 0.1 pc.

New upper limits for atmospheric constituents on Io

A spectrum of the satellite of Jupiter, Io, from 0.86 to 2.7 μm at a resolution of 3.36 cm −1 and a signal to rms noise ratio of 120 is presented. No absorptions due to any atmospheric constituents on Io could be found on the spectrum. Upper limits of 0.12 cm-atm for NH 3, 0.12cm-atm for CH 4, 0.4cm-atm for N 2O, and 24cm-atm for H 2S were determined. Laboratory spectra of ammonia frosts as a function of temperature were compared with the spectrum of Io and showed as a frost not to be present at the surface of Io. A search for possible resonance lines of carbon, silicon, and sulfur as well as the 1.08μm line of helium proved negative and upper emission limits of 60, 18, 27, and 60 kilorayleighs, respectively, were established for these lines.

Absorption coefficients of sulfur dioxide microwave rotational lines

New calculations of the absorption coefficients of the rotational transitions of 32S 16O 2 are given for all energy levels up to J = 50 and frequencies less than 200 GHz. A spectrometer incorporating a semiconfocal Fabry-Perot resonant cavity and operating in the vicinity of 70 GHz is described. The calculated absorption coefficients are compared to measured values obtained with this spectrometer and to existing measurements over the frequency range 26–40 GHz. The results obtained are in general agreement to within 5–10%. A detailed knowledge of the absorption coefficient behavior as a function of frequency is of particular interest in the development of high-sensitivity SO 2 monitors, and in investigations of the kinetics of fast chemical reactions.