Electrodeless Discharge Tube Research Articles

Hyperfine structure and isotope shifts in 733.2 nm mixed forbidden line of Pb I

Studies of the hyperfine structure and isotope shifts in 733.2 nm mixed (M1+E2) multipole line of Pb I are presented. As a light source the electrodeless discharge tube was used. The high resolution spectral apparatus consisted of a silver coated Fabry-Perot etalon and a grating spectrograph combined with a CCD camera used as a detector. In the analysis of the spectra a computer simulation technique was used. The experiments with the isotope 207Pb yielded the hyperfine structure splitting constant A for the 3P1 and 1D2 levels of the 6s26p2 ground configuration. In the experiment with natural lead the isotope shifts between four stable isotopes (204, 206, 207, 208) were measured.

Hyperfine structure and Zeeman effect studies in the 6p7p-6p7s transitions in Bi II

The hfs and hfs Zeeman splitting of nine lines from the array 6p7p→6p7s as well as lines λ = 496.9 nm (6p8p 3D2→6p7s 3P2) and λ=581.8 nm (6p8s 3P0→6p7p 3D1) of Bi II have been analysed. The Zeeman effect studies were performed for transverse direction of observation and separated π; and σ components of lines. The electrodeless discharge tube containing metallic Bi was used as the light source. The spectral apparatus consisted of a sliver-coated Fabry-Perot etalon and a grating spectrograph combined with a diode array detector. In the analysis of the spectra we used the computer simulation technique. The magnetic-dipole (A) and the electric-quadruple (B) hfs constants as well as Lande-gj factors for the level 6p8p 3D2 and all levels of configurations 6p7s and 6p7p (with the exception of 6p7p 3S1) were determined. Our results are compared with recent theory and other experiments.

Zeeman patterns of infra-red Zr I lines

The Zeeman effect of Zr I lines in the infra-red region has been recorded using electrodeless discharge tubes. In this investigation, Zeeman patterns were scanned using a Fabry-Perot interferometer as a pressure scanning spectrometer, and an infra-red Ebert grating spectrometer as a monochromator. Values are given for 22 lines involving different multiplets. The level at 15 932.10 cm−1 earlier given as b3P2 has been reassigned as b3P1. Two new levels at 15 624.34 cm−1 and 16 522.23 cm−1 are identified as b3P0 and b3P2.

The spectrum of manganese in the wavelength region 0.8-2.6 µm

Using electrodeless discharge tube sources (EDT's), and a 1.5 m vacuum Ebert-mounting spectrometer, the spectrum of manganese in the wavelength region 0.82-1.97 µm has been measured. Some of the work has been concentrated on the preparation of the EDT's containing manganese halides.218 manganese lines have been measured in the actual region; of these, 84 have been identified as transitions involving energy levels of the neutral manganese atom.

Precise and Simple Determination of Isotopic Nitrogen-15 by Emission Spectrometry and Manufacture of a High-Vacuum Line for the Preparation of Electrodeless Discharge Tubes

Precise and Simple Determination of Isotopic Nitrogen-15 by Emission Spectrometry and Manufacture of a High-Vacuum Line for the Preparation of Electrodeless Discharge Tubes

Measurement and analysis of the spectrum of neutral arsenic

The atomic-emission spectrum of neutral arsenic has been remeasured from 1644 A to 1.2 μm and extended to 3.6 μm. The light source was a microwave-excited electrodeless discharge tube. Instrumentation used included two Fourier spectrometers and a number of concave grating spectrographs. The number of emission lines was increased from the published 333 lines to 1478, 1295 of which are classified as transitions between 95 odd-parity levels and 96 even-parity levels. Of these 191 levels, 104 were the result of this experimental endeavor. Of the previously known 87, 13 were newly classified and 15 reclassified as a result of our analysis. At present, 175 of the 191 levels are classified. The classifications of these levels were accomplished with the help of ab initio calculations and least-squares fitting methods. Designations are given in both LS and JK representation when possible along with calculated compositions in both representations of the levels consisting of less than 75% of a dominant eigenvector component.

Rotational analysis of the A1Π–X1Σ+ bands of 28Si34S: perturbation studies in the A1Π state

The ultraviolet bands of the A1Π–X1Σ+ system of a 28Si34S molecule were excited in emission in an electrodeless discharge tube and photographed in the fourth order of a 10.6 m Ebert grating spectrograph. Rotational analysis of thirteen bands lying in the region 2600–3000 Å was carried out. Perturbations observed in the ν = 0–7 levels of A1Π were attributed to the perturbing states e3Σ−, d3Δ, C1Σ−, and D1Δ. Origins of the bands involving ν′ = 2, 6, and 7 were found to have shifted from their expected positions, presumably due to perturbations.

The determination of 14N: 15N isotope ratios by using the (3,0) and (4,1) bandheads of the N 2 second positive system

A good linear calibration for the isotopic composition of ammonia can be obtained over the range 5–30 atom-% nitrogen-15, by using an electrodeless discharge tube excited at 2450 MHz and cooled to suppress OH emission. Reproducible relative intensities of comparable bandheads from the two transitions indicate a stable excitation temperature in the discharge tube. It is concluded that the transitions in general use, the (2,0) or (1,0), are preferable for the determination of 14N: 15N ratios.

Preparation of submicrogram nitrogen samples for isotope analysis by the GS1 emission spectrometer

A convenient method is described for the preparation of submicrogram nitrogen electrodeless discharge tubes without the addition of noble gas. The stable nitrogen isotope analysis was carried out by using the GS1 emission spectrometer whose possibilities have been teste. The preparative method described is particularly fitted for the analysis of biological samples having a low 15N enrichment.

Some observations on the slab-line cavity developed for the excitation of electrodeless discharge sources

The design approach which leads to a simple new cavity structure, the slab-line cavity, for a microwave-excited electrodeless discharge light source, is outlined. The magnitude of the microwave impedance of a low-pressure neon electrodeless discharge was found to vary between 0.5 and 4 k Omega depending on the gas pressure and incident microwave power. The microwave results obtained show the difficulties in evaluating the system performance and in particular in the use of microwave power as an independent variable to describe the electrodeless discharge tube behaviour in any microwave cavity.

A remeasurement of the photographic emission spectrum of neutral vanadium (V i)*

As part of a comprehensive survey and analysis of the spectrum and structure of the neutral vanadium atom, the photographic V i emission spectrum has been remeasured under uniform conditions by using VCl3 electrodeless discharge tubes, the Paschen-Runge spectrograph at Argonne National Laboratory, thorium lines as standards excited in thorium iodide electrodeless discharge tubes, and an automated self-convolution measuring technique to obtain center-of-gravity line positions of the hyperfine structures encountered. This was undertaken after finding systematic errors in the previously published spectral data which led to numerous internal inconsistencies in the early V i energy level structure analysis, and to ambiguities in spectral line classifications. From the observations of approximately 1600 V i lines and an analysis of the structure of the neutral vanadium atom based upon these observations, upon ultraviolet absorption measurements, and upon measurements of the extra photographic infrared spectrum, which will be presented in later articles, it is apparent that an improvement of about an order of magnitude in wave-number uncertainty has been achieved, with uncertainties in general less than 0.05 cm−1.

A Microwave Slab Line Cavity for the Excitation of Electrodeless Discharge Tubes

A new form of microwave cavity, operating at 2.45 GHz, is described for use with electrodeless discharge tubes. The size and electrical operating conditions of the cavity may be changed readily. The second spectrum of helium, neon and argon has been strongly excited, using a sealed low pressure electrodeless discharge tube, in the new cavity.

Observation et Classification du Spectre d'Arc du Tellure (Te I) entre 3 678 et 11 761 cm-1

The spectrum emitted by an electrodeless discharge tube filled with pure 130Te has been investigated by Fourier transform spectroscopy. The observations have led to a list of wavenumbers and estimated intensities for 277 lines in the range 3 678 to 11 761 cm-1. Zeeman structures for 90 lines were studied. 70 levels, 65 of them being new, have been found and 170 lines have been classified. For these levels the energy is given with an accuracy equal to 0.005 cm-1. Landé factors for 46 levels have been measured with an accuracy up to 0.003 U.L. Parametric studies performed on 5s25p3-(6s+7s+5d+6d) configurations on the one hand and on 5s25p3(6p+7p) on the other hand, give a good interpretation for most of the levels; the r.m.s. deviation of the level energy between theory and experiment is equal to roughly 30 cm-1.

Studies in atomic fluorescence spectrometry: Part III. The determination of tin in steels

A method has been developed for the determination of tin in steel based on the atomic fluorescence of tin at the 303.4-nm line in an argon-separated air-acetylene flame (detection limit 0.05 p.p.m.) or argon-oxygen-hydrogen flame (detection limit 0.01 p.p.m.). A temperature-controlled, electronically modulated electrodeless discharge tube was used as the source. The effects of interferences were eliminated by addition of iron(III) chloride to the calibration standards in about the same amount as found in the sample and by removal of silicon from the sample. The preferred procedure involves dissolution of the sample in aquaregia followed by either the volatilization of silicon tetrafluoride or filtration of silicic acid. Tin can be determined in steels without any preconcentration step.

Classification du Spectre d'Arc du Sélénium (Sel) entre 3 900 et 11 844 cm-1

The spectrum emitted by an electrodeless discharge tube filled with pure 80Se has been newly investigated by Fourier transform spectroscopy. The observations have led to a list of wavenumbers and estimated intensities for 360 lines in the range 3 900 to 11 844 cm-1. The values of the known energy levels involved in the observed transitions have been improved by exploiting the high wavenumber accuracy, 3 × 10-3 cm-1. The fine structures of the 4p3(4S)nd5D and 3D terms have been improved and 3 levels with J=0 are new. The fine structures of the 4p3(4S)nf5F and 5F terms, which were not resolved in previous studies, are given from n=4 to n=6. It is shown that the principal quantum numbers n are in error by one unit in the compilation Atomic Energy Levels Vol. II (1952). Finally, the very regular 4p3(4S)nf5F5 series yields for the principal ionization energy of Se I the value:IP = 78 658.12 ± 0.1 cm-1 (9.747 ± 0.001 eV).

A New Band System Of Cucl Molecule

Abstract A new violet-degraded band system was recorded in the 6900–7500 Å region in the emission spectrum of a microwave excited electrodeless discharge tube containing isotopic CuCl. A vibrational analysis of the system shows that the emitter is the CuCl molecule and that its lower state is most likely the ground state of the molecule. The 63Cl bands (computed origins) of this system are represented by the formula Isotope shift data support the assignment of the band system to CuCl molecule and the proposed vibrational numbering.

Studies in atomic fluorescence spectrometry : Part I. Inexpensive methods of improving signal-to-noise ratios

The simple inexpensive adaptation of a conventional flame spectrometer for sensitive measurements of atomic fluorescence signals is described. The modifications include a home-built lock-in amplifier and pre-amplifier, high-frequency modulation of electrodeless discharge tubes, an optical system with 3 mirrors and a lens, and argon separation of an air-acetylene flame. The detection limits for the atomic fluorescence of tin range from 0.38 to 0.065 p.p.m. for time constants of 4.7 and 103.4 s, respectively. These figures compare favourably with both atomic fluorescence and atomic absorption detection limits obtained previously.

Some Observations Concerning Thallium Electrodeless Discharge Tubes

Abstract The suitability of thallium halide electrodeless discharge tubes as a radiation source for atomic fluorescence was investigated. Effects of various parameters, affecting the emission intensities, were investigated.

Etude des spectres d'émission atomique du néon et du xénon entre 3,5 et 5,5 μm à l'aide d'un spectromètre à grilles

It has been possible to observe spontaneous emission lines of Neon and Xenon with s Girard grid spectrometer up to 5.5 μm. We obtained a limit of resolution of 0.060 cm −1. The source used was an electrodeless discharge tube with a sapphire window.

Zeeman Effect of P ii*

Electrodeless-discharge tubes operated in a field of 32 215 G have given Zeeman patterns for 223 P ii spectral lines from 2285 to 7846 Å and yielded 76 Landé g factors. There is good agreement between these g values and those calculated from wave functions obtained by least-squares fitting of energy levels for the single configurations, 3p4p, 3p5p, 3p4f, 3p4s, 3p5s, and 3p6s. However, even when configuration interaction is introduced in the multiconfiguration case, 3s3p3–3p3d–3p4d–3p5d, experimental energy levels will not give good agreement with the corresponding calculated values unless LS-dependent parameters are used in the least-squares fitting. The newly obtained g factors, combined with the predictions of the least-squares energy-level fitting process, have forced a rejection of one even and two odd previously found levels, established nine new levels, reclassified three even and ten odd levels. The new levels belong to the now completed configurations 3p5p and 3p5d. A careful search for transitions to support poorly established levels yielded 44 new lines that confirm newly found levels and fill gaps in the previously known level array.