Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry

Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry

Bibliographic Details
Main Author: Hua, Wei
Language:English
Published: The Ohio State University / OhioLINK 2013
Subjects:
Environmental Science
Chemistry
Atmospheric Chemistry
Physical Chemistry
Analytical Chemistry
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1385593745
id ndltd-OhioLink-oai-etd.ohiolink.edu-osu1385593745
record_format oai_dc
collection NDLTD
language English
sources NDLTD
topic Environmental Science
Chemistry
Atmospheric Chemistry
Physical Chemistry
Analytical Chemistry
spellingShingle Environmental Science
Chemistry
Atmospheric Chemistry
Physical Chemistry
Analytical Chemistry
Hua, Wei
Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
author Hua, Wei
author_facet Hua, Wei
author_sort Hua, Wei
title Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
title_short Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
title_full Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
title_fullStr Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
title_full_unstemmed Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry
title_sort interfacial water organization and ion distributions investigated with vibrational sum frequency spectroscopy: answering fundamental questions for environmental chemistry
publisher The Ohio State University / OhioLINK
publishDate 2013
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1385593745
work_keys_str_mv AT huawei interfacialwaterorganizationandiondistributionsinvestigatedwithvibrationalsumfrequencyspectroscopyansweringfundamentalquestionsforenvironmentalchemistry
_version_ 1719435050827644928
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu13855937452021-08-03T06:20:51Z Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy: Answering Fundamental Questions for Environmental Chemistry Hua, Wei Environmental Science Chemistry Atmospheric Chemistry Physical Chemistry Analytical Chemistry Knowledge of interfacial water organization and ion distributions is necessary to elucidate questions regarding atmospheric aerosol chemistry, thundercloud electrification, geochemistry, and ocean surface processes, among others. Water organization at air/aqueous interfaces is strongly influenced by inorganic ions, specifically, ion distributions that exist in the interfacial region, where the molecular environment changes from three-dimensions to two-dimensions. Over the past century, the study of water has been a major focus of experimental and theoretical work. Although much progress has been made, interfacial water behavior and ion distributions are still incompletely understood. Here, interface-specific nonlinear optical spectroscopies, conventional vibrational sum frequency generation (VSFG) and heterodyne-detected vibrational sum frequency generation (HD-VSFG), are employed to probe interfacial water molecules at the molecular level. HD-VSFG spectroscopy allows for direct interrogation of the average orientation of the transition dipole moment of interfacial water molecules that is intrinsically contained in the sign of the second-order nonlinear susceptibility, X(2). The water organization and ion distributions at air/aqueous interfaces of inorganic salt solutions are inferred from Im X(2) spectra obtained by HD-VSFG spectroscopy.It is shown here that salt purity grade and/or pretreatment have a tremendous impact on the interfacial water spectrum of aqueous salt solutions. It is determined that the presence of trace organic contamination is primarily responsible for spectral distortion for the bare air/ aqueous interfaces of salt solutions while the presence of trace polyvalent cations proves to be critical in exploring the alkali cation-carboxylate binding and comparing relative binding affinity of different cations at the air/aqueous surfactant interfaces. A standard pretreatment procedure for inorganic salts and their solutions is established for VSFG spectroscopy via a series of systematic studies.Results indicate that the ion-induced interfacial electric field is in the opposite direction for solutions containing sulfate and carbonate salts relative to solutions of chloride, nitrate and perchlorate salts. It is found that bicarbonate and its counterion do not significantly perturb the interfacial water organization. These findings are attributed to charge separation, or lack thereof, arising from ion distributions within the air/aqueous interfaces tested. It is also suggested that the cation identity (lithium, sodium, ammonium, magnesium) as well as the concentration changes result in the partial reversal of the net direction of the interfacial electric field in the nitrate salt solutions.These findings have great significance for understanding the differences observed in aerosol reactivity as a function of aerosol salt composition. In addition, we now have a better understanding of cloud droplet electrification and ocean surface properties. Moreover, a fundamental appreciation of ions at aqueous surfaces has been gained such that we now know that monovalent anions exist in the interfacial region and on average above their counterions. However, high valency anions exist below their counter cations, causing a reversal in electric field direction. Although various specific ion properties such as polarizability, size, charge (surface charge density), geometry (shape) have been suggested to account for interfacial ion distribution, it is indicated here that charge effect exerts a greater impact than the other factors in the case of oxyanions. 2013 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1385593745 http://rave.ohiolink.edu/etdc/view?acc_num=osu1385593745 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

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