Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry
Atmospherically-relevant surface reactions were studied. These reactions were investigated to provide insight into the products formed on sea salt atmospheric particle surfaces, the quantitative distribution of species on the surface of model sea salt particles, and the molecular environment of the...
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ftunivarizona:oai:repository.arizona.edu:10150/284312 2023-05-15T15:19:12+02:00 Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry Zangmeister, Chistopher Douglas Pemberton, Jeanne E. 2001 http://hdl.handle.net/10150/284312 en_US eng The University of Arizona. http://hdl.handle.net/10150/284312 3026554 .b42177406 Copyright © 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. Chemistry Analytical Physics Atmospheric Science text Dissertation-Reproduction (electronic) 2001 ftunivarizona 2020-06-14T08:07:44Z Atmospherically-relevant surface reactions were studied. These reactions were investigated to provide insight into the products formed on sea salt atmospheric particle surfaces, the quantitative distribution of species on the surface of model sea salt particles, and the molecular environment of the interfacial region of HNO₃/H₂O ices. The reactions of model sea salt particles (NaCl) exposed to mineral acids (HNO₃ and H₂SO₄) were studied using Raman spectroscopy and atomic force microscopy (AFM). The reaction of powdered NaCl with HNO₃ was studied using Raman spectroscopy. NaNO₃ growth was monitored as a function of HNO₃ exposure in a flow cell. Mode-specific changes in the NO₃- vibrational mode intensities with HNO₃ exposure suggest a rearrangement of the NaNO₃ film with coverage. In the absence of H₂O, intensities of NaNO₃ bands increase with HNO₃ exposure until a capping layer of NaNO₃ forms. The capping layer prevents subsequent HNO₃ from reacting with the underlying. The reaction of NaCl with H₂SO₄ is investigated using Raman spectroscopy and atomic force microscopy (AFM). Raman spectra are consistent with the formation of NaHSO4 with no evidence for Na₂SO₄. The spectra indicate that the phase of NaHSO₄ varies with the amount of H₂O in the H₂SO₄. The reaction produces anhydrous β-NaHSO₄ which undergoes a phase change to anhydrous α-NaHSO₄. AFM measurements on NaCl (100) show the formation of two distinct types of NaHSO4 structures consistent in shape with α-NaHSO₄ and β-NaHSO₄ . Model sea salt particles were gown from solution to determine the surface Br/Cl of crystals grown from solution. These studies show surface Br concentration is 35 times that of the bulk concentration. This data is useful in the understanding of enhanced volatile Br compounds in the Arctic troposphere. Thin films of model polar stratospheric cloud (PSC) surfaces were studied in ultrahigh vacuum. Low temperature data show the preferential orientation of HNO₃ on crystalline H₂O ice. Thermodynamically-stable HNO₃ · 3H₂O is formed at ∼170 K, and subsequently desorbs from the surface. These studies show the chemical specificity of Raman spectroscopy in this chemical system. Studies of ClONO₂ adsorption onto crystalline H₂O ice suggest that ClONO₂ is weakly adsorbed. Thesis Arctic The University of Arizona: UA Campus Repository Arctic |
institution |
Open Polar |
collection |
The University of Arizona: UA Campus Repository |
op_collection_id |
ftunivarizona |
language |
English |
topic |
Chemistry Analytical Physics Atmospheric Science |
spellingShingle |
Chemistry Analytical Physics Atmospheric Science Zangmeister, Chistopher Douglas Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
topic_facet |
Chemistry Analytical Physics Atmospheric Science |
description |
Atmospherically-relevant surface reactions were studied. These reactions were investigated to provide insight into the products formed on sea salt atmospheric particle surfaces, the quantitative distribution of species on the surface of model sea salt particles, and the molecular environment of the interfacial region of HNO₃/H₂O ices. The reactions of model sea salt particles (NaCl) exposed to mineral acids (HNO₃ and H₂SO₄) were studied using Raman spectroscopy and atomic force microscopy (AFM). The reaction of powdered NaCl with HNO₃ was studied using Raman spectroscopy. NaNO₃ growth was monitored as a function of HNO₃ exposure in a flow cell. Mode-specific changes in the NO₃- vibrational mode intensities with HNO₃ exposure suggest a rearrangement of the NaNO₃ film with coverage. In the absence of H₂O, intensities of NaNO₃ bands increase with HNO₃ exposure until a capping layer of NaNO₃ forms. The capping layer prevents subsequent HNO₃ from reacting with the underlying. The reaction of NaCl with H₂SO₄ is investigated using Raman spectroscopy and atomic force microscopy (AFM). Raman spectra are consistent with the formation of NaHSO4 with no evidence for Na₂SO₄. The spectra indicate that the phase of NaHSO₄ varies with the amount of H₂O in the H₂SO₄. The reaction produces anhydrous β-NaHSO₄ which undergoes a phase change to anhydrous α-NaHSO₄. AFM measurements on NaCl (100) show the formation of two distinct types of NaHSO4 structures consistent in shape with α-NaHSO₄ and β-NaHSO₄ . Model sea salt particles were gown from solution to determine the surface Br/Cl of crystals grown from solution. These studies show surface Br concentration is 35 times that of the bulk concentration. This data is useful in the understanding of enhanced volatile Br compounds in the Arctic troposphere. Thin films of model polar stratospheric cloud (PSC) surfaces were studied in ultrahigh vacuum. Low temperature data show the preferential orientation of HNO₃ on crystalline H₂O ice. Thermodynamically-stable HNO₃ · 3H₂O is formed at ∼170 K, and subsequently desorbs from the surface. These studies show the chemical specificity of Raman spectroscopy in this chemical system. Studies of ClONO₂ adsorption onto crystalline H₂O ice suggest that ClONO₂ is weakly adsorbed. |
author2 |
Pemberton, Jeanne E. |
format |
Thesis |
author |
Zangmeister, Chistopher Douglas |
author_facet |
Zangmeister, Chistopher Douglas |
author_sort |
Zangmeister, Chistopher Douglas |
title |
Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
title_short |
Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
title_full |
Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
title_fullStr |
Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
title_full_unstemmed |
Chemistry of alkali halide and ice surfaces: Characterization of reactions relevant to atmospheric chemistry |
title_sort |
chemistry of alkali halide and ice surfaces: characterization of reactions relevant to atmospheric chemistry |
publisher |
The University of Arizona. |
publishDate |
2001 |
url |
http://hdl.handle.net/10150/284312 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
http://hdl.handle.net/10150/284312 3026554 .b42177406 |
op_rights |
Copyright © 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. |
_version_ |
1766349383309197312 |