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dc.contributor.advisorDenton, M. Bonneren_US
dc.contributor.authorSmith, Thomas Riddell.
dc.creatorSmith, Thomas Riddell.en_US
dc.date.accessioned2011-10-31T17:12:34Z
dc.date.available2011-10-31T17:12:34Z
dc.date.issued1988en_US
dc.identifier.urihttp://hdl.handle.net/10150/184582
dc.description.abstractSpectroscopic investigations have been carried out on an argon inductively coupled plasma operating at non-atmospheric pressure. The relationship between torch pressure and a number of plasma operating characteristics was explored for torch pressures between 100 and 3000 torr. The plasma operating characteristics examined include observed analyte emission intensities, electron densities, ion to atom ratios, and the deviation of plasma conditions from local thermodynamic equilibrium. The effect of pressure on the observed analyte emission intensities was found to include factors in addition to the change in density of species within the torch. Emission lines originating from ions and atoms with high ionization potentials (greater than 7 eV) increased in intensity with increasing torch pressure, in excess of that predicted by the increase in density of species present. Conversely, emission lines originating from atoms of low ionization potential decreased in intensity with increasing torch pressure despite the increase in density. The results of the spatial determination of electron densities and ion to atom ratios indicate that excitation conditions within the central channel of the plasma are shifted towards conditions of local thermodynamic equilibrium as the pressure within the torch is increased. In addition, it is possible to obtain improved limits of detection by optimizing the torch pressure for the analyte element of interest.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectPlasma spectroscopy -- Research.en_US
dc.subjectPlasma (Ionized gases) -- Research.en_US
dc.titleExcitation processes within an inductively coupled plasma as a function of pressure and related studies.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc701857975en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberFernando, Quintusen_US
dc.contributor.committeememberBurke, Michaelen_US
dc.contributor.committeememberMiller, Walteren_US
dc.contributor.committeememberHall, Henryen_US
dc.identifier.proquest8906392en_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-22T19:44:51Z
html.description.abstractSpectroscopic investigations have been carried out on an argon inductively coupled plasma operating at non-atmospheric pressure. The relationship between torch pressure and a number of plasma operating characteristics was explored for torch pressures between 100 and 3000 torr. The plasma operating characteristics examined include observed analyte emission intensities, electron densities, ion to atom ratios, and the deviation of plasma conditions from local thermodynamic equilibrium. The effect of pressure on the observed analyte emission intensities was found to include factors in addition to the change in density of species within the torch. Emission lines originating from ions and atoms with high ionization potentials (greater than 7 eV) increased in intensity with increasing torch pressure, in excess of that predicted by the increase in density of species present. Conversely, emission lines originating from atoms of low ionization potential decreased in intensity with increasing torch pressure despite the increase in density. The results of the spatial determination of electron densities and ion to atom ratios indicate that excitation conditions within the central channel of the plasma are shifted towards conditions of local thermodynamic equilibrium as the pressure within the torch is increased. In addition, it is possible to obtain improved limits of detection by optimizing the torch pressure for the analyte element of interest.


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