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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Molecular spectroscopy of ionic and neutral species in the gas phase

Cramb, David Thomas January 1990 (has links)
This thesis details the analyses of high resolution visible, infrared, and microwave spectra of gas phase ionic and neutral molecules. The visible and infrared spectra of several ions were measured using velocity modulation spectrometers developed in the present work. In each case the ions were generated in an electric discharge plasma. The microwave spectrum of vinyl iodide, CH₂=CHI, has been extensively measured and analysed. Visible Spectroscopy using Velocity Modulation: The (6,1) and (13,6) vibrational bands of the A²IIu — X²Σg⁺ electronic transition of N₂⁺ have been recorded in absorption at Doppler limited resolution. The rotational fine structure was fitted by least squares to standard expressions. The rotational and translational temperatures have been measured and indicate an equilibrium between translational and rotational motion in the He/N₂ plasma. Infrared Spectroscopy using Velocity Modulation: The infrared spectra of HCO⁺, H₃⁺ , HeD⁺, and N₂⁺ have been observed. Two previously unmeasured lines of the v₃ band of HCO⁺ and several previously measured lines of the v₂ band of H₃⁺ were used to adjust the spectrometer for maximum sensitivity. A new line in the rotational fine structure of the v = 1 ← 0 band of HeD⁺ was analysed using standard expressions. The rotational fine structure of the (2,5) vibrational band of the A²IIu — X²Σg⁺ electronic transition of N₂⁺ has been recorded and analysed in the region 2125 - 2205 cm⁻¹. Using the vibrational origin, T₂,₅ , obtained from this analysis combined with the origins, T₆,₁ and T₁₃,₆, obtained from the analyses of the visible spectra of N₂⁺ , it was possible to determine third order equilibrium vibrational coefficients for both the X²Σg⁺ and A²IIu states. Microwave Spectroscopy: The microwave spectrum of vinyl iodide, in its ground and first excited vibrational states, has been measured in the frequency range 20 - 108 GHz. The spectrum contains strong a-type transitions and very weak b-type transitions; all contain ¹²⁷I quadrupole hyperfine structure, with several large perturbations. A procedure specially devised for analysis of such spectra, which takes advantage of the perturbations, was applied to produce accurate values of constants that are otherwise unobtainable, and have permitted assignment of some b-type transitions. Also, as a result of this procedure, it was possible to measure both components of the dipole moment with relative ease. The centrifugal distortion constants and inertial defects have been compared with those calculated from a published harmonic force field, modified for the out-of-plane vibrations. A partial structure has been obtained. / Science, Faculty of / Chemistry, Department of / Graduate
22

Development of an ion trap mass spectrometer for elemental analysis

Daigle, J.A. Bernard January 1990 (has links)
Mass spectrometry is a widely used technique for the performance of elemental analysis: not only does it provides excellent limits of detection for a large number of elements, but it is also able to provide information about the isotopic distribution of the analyte. The radio-frequency quadrupole ion trap is a relatively new design of mass spectrometer, which offers the ability to confine charged particles for extended periods of time in a well defined volume by applying a radio-frequency oscillating voltage to an arrangement of three electrodes. A mass analysis of the trapped ions can be obtained by selectively extracting the ions from the cavity of the trap, where they can be detected by an electron multiplier. Despite its unique capabilities, to date the applications of the ion trap mass spectrometer have mostly been restricted to gas chromatography detection. Until recently, there have been very few attempts to use it for any other types of routine analysis. Our interest lies in the development of an instrument capable of performing a complete mass spectrometric elemental analysis of small volume liquid samples (a few (μL) at trace or ultra-trace concentration levels. The ability of the ion trap to accumulate ions in its cavity and to provide an entire mass spectrum of these ions in a single scan of the radio-frequency oscillating voltage applied between the electrodes, makes it a very interesting candidate for the ultra-trace analysis of small size samples. However, to perform an analysis on a sample with the ion trap the sample must first be vaporized; and if an elemental analysis is required, the sample will also have to be atomized. The graphite furnace atomizer used in atomic absorption spectroscopy offers a number of advantages which make it potentially useful for this purpose: it has a high transport efficiency of the analyte from liquid or solid state to the vapour phase, the ionization of the analyte in the furnace is very low (as required by the ion trap) and it handles small volume samples very well. A graphite furnace ion trap mass spectrometer was designed to fulfil the need of having instrumentation capable of multielemental mass spectrometric analysis of small volume samples containing traces of the analytes of interest. This document contains a description of the principles of operation of the ion trap as well as a detailed description of the instrument actually built. Data are presented in order to assess the capabilities of the instrument, as well as some of the problems encountered with it. The results obtained with the graphite furnace ion trap mass spectrometer allow us to conclude that the proposed design is not appropriate for the performance of elemental analysis, but is appropriate for mass spectrometric study of low boiling point compounds which can interfere with atomic absorption analysis: it is calculated that these compounds could be analysed at the ppm level. Promising results obtained with a set up in which the analyte is vaporized directly into the cavity of the ion trap through laser ablation are also presented. These limited results show the potential of this methodology for direct elemental analysis of solid samples. / Science, Faculty of / Chemistry, Department of / Graduate
23

Electronic raman spectroscopy of iron doped MgO

Poirier, Alain January 1982 (has links)
No description available.
24

BEAM-FOIL STUDIES OF ATOMIC MEAN-LIVES IN THE VACUUM ULTRAVIOLET

Rathmann, Peter Walden January 1981 (has links)
The beam-foil method was used to determine mean-lives of excited atomic states. Initial studies were done on states. Initial studies were done on states of the helium- and hydrogen-like ions B IV and B V, with the mean-lives determined by fitting the decay curves to sums of exponential terms. Since theoretical values of the mean-lives are very precise in these simple atomic systems, our results indicate the accuracy of the experimental method. A series of measurements was made of the low lying 2s 2p⁴ states in nitrogen-like Ne IV, Na V, Mg VI, Al VII, and Si VIII. The experimental results were compared to theoretical calculations of Fawcett and Sinanoglu, and showed excellent agreement with Sinanolu's nonclosed-shell many electron theory. The lifetimes of the 4p ²P₁/₂ and 4p ²P₃/₂ states in copper-like Br VII were determined by measuring decay curves for both the primary and cascade decays and then analyzing the curves jointly. Our resulting mean-life values are considerbly shorter than those of previous experiments which analyzed only the primary decay curve. Comparison with theoretical calculations showed excellent agreement with those which include core polarization effects.
25

Cryptates and pendant arm ligand complexes / by Ashley Stephens

Stephens, Ashley January 1994 (has links)
Includes bibliographies. / xi, 240 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The complexation of a range of monovalent and divalent metal ions by the aliphatic bridge cryptands C22C2 and C22C8; and the complexation of alkali metal ions by the pendant arm tetraaza macrocycle 1,4,7,10-tetrakis(2-methoxyethyl)1,4,7,10-tetraazacyclododecane, and the factors effecting complex stability and lability, have been investigated. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1995
26

Two-body operators and correlation crystal field models

盧德成, Lo, Tak-shing. January 1993 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
27

Chromatography coupled with mass spectrometry in bioanalysis

Xia, Yang 12 1900 (has links)
No description available.
28

X-ray absorption studies of metal-imidazole complexes

Furenlid, Lars Ragnar 08 1900 (has links)
No description available.
29

A stability and mechanistic study of pendant arm ligand complexes / by Sonya L. Whitbread.

Whitbread, Sonya L. January 1999 (has links)
Erratum pasted onto front-end paper. / Includes bibliographical references. / xi, 225 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates alkali and alkaline earth complexes of pendant arm ligands. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999
30

A structural thermodynamic and equilibrium study of chiral pendant arm triaza macrocyclic ligand complexes: towards the formation of metal-ion activated molecular receptors : a thesis submitted for the degree of Doctor of Philosophy at the University of Adelaide (Faculty of Science) / by Jennifer Megan Weeks.

Weeks, Jennifer Megan January 2000 (has links)
Errata page pasted opposite title page. / Includes bibliographical references. / x, 147 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Addresses the structural, equilibrium and thermodynamic aspects of pendant arm donor triaza macrocyclic ligands and their alkali metal and zinc complexes. Involves ab initio molecular modelling, x-ray crystallographic studies, potentiometric stability constant determinations and NMR kinetic studies. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 2000?

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