<mods:mods xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-4.xsd"><mods:titleInfo><mods:title>Dynamics of Hydrogen Bond Networks in the Condensed Phase: Ultrafast X-ray Absorption Spectroscopy</mods:title></mods:titleInfo><mods:name type="personal"><mods:namePart>Jiao, Yishuo</mods:namePart><mods:role><mods:roleTerm type="text">creator</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Rose-Petruck, Christoph</mods:namePart><mods:role><mods:roleTerm type="text">Advisor</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Doll, Jimmie</mods:namePart><mods:role><mods:roleTerm type="text">Reader</mods:roleTerm></mods:role></mods:name><mods:name type="personal"><mods:namePart>Wang, Lai-Sheng</mods:namePart><mods:role><mods:roleTerm type="text">Reader</mods:roleTerm></mods:role></mods:name><mods:name type="corporate"><mods:namePart>Brown University. Department of Chemistry</mods:namePart><mods:role><mods:roleTerm type="text">sponsor</mods:roleTerm></mods:role></mods:name><mods:originInfo><mods:copyrightDate>2017</mods:copyrightDate></mods:originInfo><mods:physicalDescription><mods:extent>xxi, 136 p.</mods:extent><mods:digitalOrigin>born digital</mods:digitalOrigin></mods:physicalDescription><mods:note type="thesis">Thesis (Ph. D.)--Brown University, 2017</mods:note><mods:genre authority="aat">theses</mods:genre><mods:abstract>The primary objective of this thesis is the development of methods to generate and detect local phonons in aqueous solutions, which lead to new understanding of the contentious hydrogen bond network study in aqueous solutions. Pump-probe experiments with ultrafast x-ray absorption spectroscopy were conducted to study the solvation dynamics in liquid water. Acoustic phonons in aqueous solutions were generated with strong laser electric field created transient gratings. Metal complexes were used as probe molecules to study dynamics of solvent shell around. With the proper design of a 2ps time resolution streak camera, phonons that exist locally with energy for as low as ~56μeV can be detected and this strategy can be applied to low-concentration, low ionic-strength samples such as in the millimolar, univalent ion solutions.
Specifically, in 50mM KMnO4 solution, 13.5GHz longitudinal phonons and second harmonic 27GHz transverse phonons were detected simultaneously. In addition, 27GHz phonons were also detected in 30mM K4Fe(CN)6 aqueous solutions and were characterized to propagate with a speed of ~3000m/s, the so-called “fast-sound” speed. These experimental results indicate that aqueous solutions at room temperature can contain mesoscopic, ice-like domains. These domains are solute-dependent, and can retain their ice-like rigidity for at least 40 picoseconds. The domain sizes can be estimated to range from tens to several hundreds of nanometers. These results can serve as an experimental validation for a recent simulation result that water is more “ice-like” than previously believed and can support phonon propagating along the hydrogen bond network.
Clathrate Hydrates are nano-scaled caging structure mainly composed of water molecules, with a guest gas molecule like N2, CH4, or CO2 trapped in the cage. These hydrates were tested to be able to shift the products of CO2 electrochemical reduction reactions. Preliminary results lead to a hypothesis that some electrochemical reduction may happen in the Hydrates cage, which indicates a possible new approach of improving CO2 reduction efficiency.
</mods:abstract><mods:subject><mods:topic>Spectroscopy</mods:topic></mods:subject><mods:subject authority="fast" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/01061299"><mods:topic>Phonons</mods:topic></mods:subject><mods:subject authority="fast" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/01743572"><mods:topic>Saltwater solutions</mods:topic></mods:subject><mods:language><mods:languageTerm authority="iso639-2b">English</mods:languageTerm></mods:language><mods:recordInfo><mods:recordContentSource authority="marcorg">RPB</mods:recordContentSource><mods:recordCreationDate encoding="iso8601">20170616</mods:recordCreationDate></mods:recordInfo><mods:identifier type="doi">10.7301/Z09885G0</mods:identifier><mods:accessCondition type="rights statement" xlink:href="http://rightsstatements.org/vocab/InC/1.0/">In Copyright</mods:accessCondition><mods:accessCondition type="restriction on access">Collection is open for research.</mods:accessCondition><mods:typeOfResource authority="primo">dissertations</mods:typeOfResource></mods:mods>