Large Quartz Spectrograph Research Articles

Spectrographic analysis of refractory magnesium oxide: A buffer approach

A method has been described for the determination of eighteen trace elements in refractory magnesium oxide by optical emission spectroscopy. The main feature of the method is the use of a spectroscopic buffer instead of a carrier. When conducting graphite powder has been added as a buffer to the MgO sample prior to its excitation in a d.c. arc, there has been a smooth distillation of the matrix magnesium as well as the trace elements into the arc column. Addition of a carrier, however, does not either completely prevent the emission of Mg spectrum or result in smooth distillation. A Hilger large quartz spectrograph has been employed to record the spectra excited at 10 amp d.c. The Ga line at 265.99 nm has been used as an internal standard for the more volatile trace elements and the Mg line at 280.98 nm has been employed as an internal standard for the less volatile trace elements. The detection limits obtained range from 0.5–5 ppm for the various elements. The mean relative standard deviation (RSD) of the method is ± 14%.

A Carrier Distillation Method for Estimation of Boron in CaF2

Abstract A carrier distillation method is described for determination of boron in calcium fluoride. The sample is mixed with 5 % copperoxyfluoride containing 200 ppm of gallium. 50 mg of this mixture is loaded in pre-arced U. C. C. 1990 electrode and excited using 15 amp. d. c. arc. The resulting spectra are recorded in the region 2200 to 2850 A employing Hilger large quartz spectrograph. The detection limit for boron is 0.1 ppm and the precision of the method is ± 12%.

Spectrographic a.c. spark method for the estimation of yttrium in rare earth mixtures

The spectrographic estimation of yttrium in rare earth mixtures was achieved within a concentration range of 1–90% by means of the a.c. spark method using a large quartz spectrograph. The sample was mixed with ceria and zinc oxide in the ratio 2∶1∶2. The Y lines 2414.68 A and 2856.36 A were used as analytical lines for the ranges of 1–15% and 10–90%, respectively. The Ce line at 2603.65 A served as internal standard line. The standard deviation was 2–5%.

π-π* Absorption Spectrum of Pyridine-D5

The absorption spectrum of π–π* system of pyridine-D5 molecule has been measured in the range 33790–36990 cm−1, on the Hilger large quartz spectrograph. A large number of sharp bands have been measured and analyzed in terms of ground and excited state frequencies which have been compared with the corresponding frequencies of pyridine-H5 molecule.

Ultraviolet Absorption Spectrum of Toluene‐D8

AbstractThe near ultraviolet absorption spectrum of toluene‐d8 has been recorded with the help of a E1 large quartz spectrograph. The (O,O) band has been identified at 37672 cm−1. The spectrum has been analysed with the help of the excited state fundamentals 282, 378, 431, 454, 508, 700, 926, 1150 and 1432 cm−1. These frequencies have been correlated with the corresponding frequencies of the normal molecule. The ration R = ν(C6H5CH3)/ν(C6D5CD3) has been calculated for each excited state mode of vibration and compared with the corresponding value of R found for the ground state vibrations.

The π-π* Electronic Absorption Spectra of p-Dibromobenzenes-D4 and -H4

The uv absorption spectra of p-dibromobenzenes-H4 and – D4 have been recorded on a Hilger E1 large quartz spectrograph in the regions 35370–39540 cm−1 and 35340–39470 cm−1, respectively. The assignments of vibronic bands have been made using the results from the two isotopic molecules. Some of the previous assignments have been revised in the light of the data from the present investigations.

Spectrographic method for the determination of rare earths in plutonium—use of trilaurylamine

A spectrographic method for the estimation of some rare earths (Gd, Sm, Dy, Er and Ce) in plutonium samples is described. The rare earths were separated from 100 mg of plutonium by extracting plutonium with trilaurylamine. After concentration of the solution, the spectrum was photographed on a Hilger large quartz spectrograph, with scandium as internal standard. The estimation ranges are Gd 10–100 p.p.m., Sm 50–300 p.p.m., Dy 5–100 p.p.m., Er 5–200 p.p.m. and Ce 100–600 p.p.m. The overall standard deviation is 14%. The method is applicable to samples containing calcium and iron upto 1000 p.p.m. The resolving power and line interferences are discussed.

Use of a large quartz spectrograph for the determination of thorium, yttrium and the rare earths in silicates

Studies were carried out on the optimum conditions for the successful use of a large quartz spectrograph for the determination of thorium, yttrium and the rare earths in silicate rocks. The best line-to-background ratios were achieved by arcing samples in a matrix of 4 % sodium chloride in carbon powder. An atmosphere of 20 % argon and 80% oxygen was used to reduce background and eliminate cyanogen band interference. An anion-exchange procedure was used to separate the rare earths from other elements. The resultant enrichment allowed use to be made of less sensitive rare earth lines in the ultraviolet end of the spectrum where the spectrographic dispersion is greater. Line interferences were studied and necessary corrections for these interferences were calculated. The technique was tested by analysing the standard rocks, G-1, W-1 and CAAS syenite. Good agreement with recommended values was obtained.

A Suggested Mechanism for the 337µ CN Maser

STIMULATED emission at a wave-length of 337µ has been observed1 from pulsed discharges in volatile cyanides in the pressure range 0.1–1.0 mm. No other stimulated emission lines from such sources have been observed so far in our experiments. This is a surprising result when we consider how many transitions are possible in a molecular system. In view of the known high dissociation energy of CN it is plausible to assume that either CN or CN+ is the emitter. We have now recorded the ultra-violet and visible spectra of the discharge using a Hilger large quartz spectrograph. No sign of the band at 3263 A [f′Σ→a′Σ] characterstic of the CN+ molecule was observed although the ‘Melinex’ windows of the maser are transparent at this wave-length. In fact all the observed bands belonged to the well-known violet and red systems of CN.

Near Ultra-violet Absorption Spectra of o-, m-, and p-Fluorophenol Vapour

THE absorption spectra of o-, m-, and p-fluorophenol in vapour phase have been examined with a Hilger E1 large quartz spectrograph. A number of plates were taken with different cell lengths and at temperatures ranging from 26° C to 60° C; while the temperature of the reservoir containing the substance varied from −15° C to 60° C. The bands in each case appear well defined with the cell of length 70 cm maintained at temperature 26° C. A hydrogen lamp was used as the source of continuum for the ultra-violet region. Ilford special rapid N.40 plates were used to photograph the spectra in about half an hour.

Measured Transition Probabilities for the Schumann-Runge System of Oxygen

Transition probabilities for the Schumann-Runge system of O2 have been measured in absorption in the wavelength region 2650–3900 A. Oxygen was heated in a shock tube to temperatures up to 4500°K, thereby populating high vibrational and rotational levels. Absorption spectra were photographed using a high-speed flash lamp and a large Littrow quartz spectrograph. Transition probabilities for the bands of three sequences, associated with the zero, 1st, and 2nd vibrational levels of the excited electronic state, yield an f value of 0.048±0.008 which, when corrected for wavelength dependence, is about ⅓ that determined in the vacuum ultraviolet. This corresponds to a decrease in transition probability with increasing internuclear separation. Line-width variations with temperature and density have also been measured. The optical diameter for O2–O2 collisions was determined as 6 A and for O2–O collisions as 10 A.

A d.c. arc method for the spectrographic determination of hafnium in zirconium

A spectrographic method is presented for the quantitative determination of hafnium in zirconium in the range 0.2%, to 5% HfO2 The sample in the form of a fine powder is burnt in a D.C. arc at 15 amp., 220 V, and the spectrum photographed with a large quartz spectrograph. he hafnia concentration is determined from the ratio of the intensities of the spectral lines HfII 2861.696 Å and ZrII 2856.065 Å. A standard deviation of ± 6% has been obtained by this method for samples essentially free from other impurities, especially Fe, Al, Mg and Na.

A spark-traverse attachment for the Hilger large quartz spectrograph

An auxiliary attachment for the Hilger large quartz spectrograph has been described, with which it is possible to guide a sample under a stationary upper electrode while the photographic plate on which the spectrogram is recorded moves downward past the camera aperture of the spectrograph. The width of the spark crater caused by this form of excitation is 0.4 mm (0.016 in.). From the resultant spectrogram, it is possible to determine quantitatively the variations in concentration of the elements Mn, Si, Ni, Cr, Mo and V over the area of sample traversed. With certain modifications of the technique it is hoped later to include carbon in the above range of elements.An illustration is given of the application of the above technique to the determination of variations in composition across a weld area.It is considered that this technique will prove of valuable assistance to the metallurgist in the examination of: (a) Concentration variation within steel segregates. (b) Variation in composition across a weld area. (c) Inclusions in steel.

The Earliest Industrial Spectrographic Installation in the United States

If, under this heading, we restrict our selection to laboratories maintained by industrial or commercial concerns for the regular, systematic use of spectrochemical emission analysis for the inspection of materials and or the control of composition and quality during production, there can be no question that our choice will be that of the American Brass Company at Waterbury, Connecticut. There, in 1913 or 1914, Charlie Davis, with the encourage and backing of his chief, W. H. Bassett, set up a large Littrow quartz spectrograph to check the purity of the copper and zinc that went into their products and to search out the reasons for variations in their properties that could not be accounted for by ordinary chemical analysis.

ROTATIONAL ANALYSIS OF THE γ BAND SYSTEM OF THE NS MOLECULE

The band heads of the NS spectrum discovered in 1932 by Fowler and Bakker have been remeasured on plates taken on a large quartz spectrograph and on first order grating plates. The (0,0) and (0,1) γ bands have been photographed in the 6th, 8th, and 9th orders of a 21 ft. concave grating, and a rotational analysis of these bands has been carried out. For the ground state (2II) it was found that [Formula: see text] = 0.77364 cm−1, [Formula: see text] = 0.00612, and A = 223.03 cm.−1 For the upper state the value [Formula: see text] = 0.82670 was obtained.

Wave-Lengths of Mercury 198

The wave-lengths of 26 visible and ultraviolet radiations from H80198g have been measured to eight figures relative to 5460.7532A, provisionally adopted for the green line. A water-cooled electrodeless lamp containing two milligrams of artificial H80198g served as a light source when excited with radio waves of 100 Mc frequency. This lamp illuminated a Fabry-Perot interferometer and a large quartz spectrograph with which the interference patterns were photographed. Measurements of these patterns yielded relative wave-lengths with probable errors usually less than 0.0001A. In addition to demonstrating that H80198g 5460.7532A provides a practically perfect primary standard of length, this paper presents preliminary values of 27 superior spectroscopic standards which show that differences among vacuum wave numbers recur within the accuracy of the measurements, and that all the existing dispersion curves for air are incorrect.

Errors in spectrochemical (flame) analysis

AbstractIn an attempt to use the equipment available for the determination of the exchangeable cations in soils, u statistical analysis has been made of the errors in the spectrochemical results obtained by means of an air‐acetylene flame and a large quartz, spectrograph. Even with an elementary technique, an average standard error of less than 4% was obtained. Factors contributing to the total error, such as the error of a microphotometer reading, fluctuations of the flame, and variations of the photographic emulsion, have been studied; two types of plate, sensitised and non‐sensitised, have been examined, It has been shown that most of the total error was due to variations in the photographic plates, and the significance of this in relation to the placement of the standard spectrograms on a plate is discussed. It has been found that, in general, a large quartz spectrograph is not suitable for use with an air‐acetylene Hume because the very low light‐collecting power of the instrument necessitates very long exposures or the use of solutions of impracticably high concentrations, or sometimes both.

A New Large Two-Lens Quartz Spectrograph of Compact Design*

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text S. Jacobsohn, "A New Large Two-Lens Quartz Spectrograph of Compact Design*," J. Opt. Soc. Am. 32, 164-167 (1942) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

The Near Ultraviolet Bands of Acetylene

The present investigation is a part of the program of a series of studies aiming at a satisfactory analysis of the near ultraviolet spectrum of acetylene. The spectrum of C2H2 at room temperature and 300°C was taken with a Bausch and Lomb large quartz spectrograph. The spectrum extends from λ2430A down to the ultraviolet limit of the instrument. More than 1000 bands and lines have been measured. Most of the bands revealed intensification at elevated temperature. Some of them have been partially resolved into rotational lines with alternating intensities. Seven main progressions all with frequency difference ∼1050 cm—1 have been found. Only the bands of three of the progressions showed no intensification at higher temperature. From the differences between these bands, a frequency 580 cm—1 has been observed. Weaker bands on the red side of stronger ones have been proved through temperature variation to be due to transitions from the excited 2v5″(Eg) level in the ground state. Through a tentative assignment, 2v5′=1050 cm—1 and v4′(Eu)=580 cm—1 and the empirical selection rules, all of the bands in the seven progressions can be satisfactorily explained. Other possible assignments and the nature of the electronic transition have also been briefly discussed.

Series of Cæsium Atoms in an Electric Field

WE have investigated the absorption spectrum of caesium vapour in an electric field by a method similar to that used by C. J. Bakker in Prof. Zeeman's laboratory1 and by E. Amaldi and E. Segre2 in studying potassium and sodium. The background was given by a high purity carbon arc. A Hilger large quartz spectrograph E1 was used. A spar crystal was placed in the light beam before the slit of the spectrograph, so that polarisations parallel to the electric field (-component) and perpendicular to it (-component) could be photographed simultaneously and separately.