Vapour-phase metals and metal oxides and the corrosion of uranium, as studied by photoelecton spectroscopy
Vapour-phase metals and metal oxides and the corrosion of uranium, as studied by photoelecton spectroscopy
A photoelectron spectrometer used to study a number of metals and metal oxides in the vapour-phase is described; particular attention is paid to the radio-frequency induction heating method used to generate sample vapours, and problems associated with recording photoelectron spectra at high temperatures (underline ≥2000 K). The spectra presented in this thesis have been assigned utilising previous experimental data derived from optical spectroscopy and electron impact mass spectrometry. Hartree-Fock-Slater DV-Xα calculations have been performed to assist a number of these spectral assignments and the theoretical methods used in these calculations are described. The photoelectron spectra of the vapours above heated arsenic and antimony have been recorded, and the use of photoelectron spectroscopy (PES) in determining the composition of these vapours, as a function of temperature, is discussed. A simple intermediate coupling model for the group V atoms has been developed and used to calculate the relative band intensities in the photoelectron spectra of these atoms. Also, Hartree-Fock-Slater molecular orbital calculations have been used to investigate the effect of relativity on the electronic structure of the homonuclear diatomics of group V. The vapour-phase He I photoelectron spectra of some of the polymeric oxides of chromium, molybdenum and tungsten have been recorded. The results obtained are consistent with the observation of (CrO_3)_3 and (CrO_3)_4 above heated CrO_3(s), (MoO_3)_3 and (MoO_3)_4 above heated MoO_3(s), and (WO_3)_3 above heated WO_3(s). The HeI photoelectron spectrum of NbO has been recorded and the experimental vertical ionisation energies compared with those predicted theoretically. This molecule has been shown to be the predominant species in the vapour above both NbO(s) and Nb_2O_5(s), under the conditions used in this study. A solid-state investigation of the behaviour of uranium metal in a hydrogen/water-vapour atmosphere has been carried out using X-ray photoelectron spectroscopy. The presence of even a small quantity of water in an excess of hydrogen was shown to result in preferential oxidation of the uranium surface, although UH_3 was detected between the surface oxide and bulk metal. Preliminary high temperature photoelectron spectra are presented for the suboxides of gallium and indium, and the lanthanides cerium and gadolinium; suggestions for future studies on these species are given. (D74045/87)
University of Southampton
Stevens, Julian Charles Hamilton
1987
Stevens, Julian Charles Hamilton
Stevens, Julian Charles Hamilton
(1987)
Vapour-phase metals and metal oxides and the corrosion of uranium, as studied by photoelecton spectroscopy.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A photoelectron spectrometer used to study a number of metals and metal oxides in the vapour-phase is described; particular attention is paid to the radio-frequency induction heating method used to generate sample vapours, and problems associated with recording photoelectron spectra at high temperatures (underline ≥2000 K). The spectra presented in this thesis have been assigned utilising previous experimental data derived from optical spectroscopy and electron impact mass spectrometry. Hartree-Fock-Slater DV-Xα calculations have been performed to assist a number of these spectral assignments and the theoretical methods used in these calculations are described. The photoelectron spectra of the vapours above heated arsenic and antimony have been recorded, and the use of photoelectron spectroscopy (PES) in determining the composition of these vapours, as a function of temperature, is discussed. A simple intermediate coupling model for the group V atoms has been developed and used to calculate the relative band intensities in the photoelectron spectra of these atoms. Also, Hartree-Fock-Slater molecular orbital calculations have been used to investigate the effect of relativity on the electronic structure of the homonuclear diatomics of group V. The vapour-phase He I photoelectron spectra of some of the polymeric oxides of chromium, molybdenum and tungsten have been recorded. The results obtained are consistent with the observation of (CrO_3)_3 and (CrO_3)_4 above heated CrO_3(s), (MoO_3)_3 and (MoO_3)_4 above heated MoO_3(s), and (WO_3)_3 above heated WO_3(s). The HeI photoelectron spectrum of NbO has been recorded and the experimental vertical ionisation energies compared with those predicted theoretically. This molecule has been shown to be the predominant species in the vapour above both NbO(s) and Nb_2O_5(s), under the conditions used in this study. A solid-state investigation of the behaviour of uranium metal in a hydrogen/water-vapour atmosphere has been carried out using X-ray photoelectron spectroscopy. The presence of even a small quantity of water in an excess of hydrogen was shown to result in preferential oxidation of the uranium surface, although UH_3 was detected between the surface oxide and bulk metal. Preliminary high temperature photoelectron spectra are presented for the suboxides of gallium and indium, and the lanthanides cerium and gadolinium; suggestions for future studies on these species are given. (D74045/87)
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Published date: 1987
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Local EPrints ID: 461103
URI: http://eprints.soton.ac.uk/id/eprint/461103
PURE UUID: c00c53c6-05b4-422e-83df-97672ef27904
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Date deposited: 04 Jul 2022 18:35
Last modified: 04 Jul 2022 18:35
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Author:
Julian Charles Hamilton Stevens
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