The Structure and Properties of Weakly Bound Clusters

dc.contributor.authorZhou, Ce
dc.date.accessioned2020-10-07T20:40:02Z
dc.date.available2020-10-07T20:40:02Z
dc.date.issued2020-10-07
dc.date.submitted2020-09-29
dc.description.abstractIn this thesis, two novel methods are introduced to advance the study of gas phase clusters. The structure similarity method is a computational technique that is able to quantify the structure difference for a pair of isomers, with a structure interpolation technique capable of finding intermediates in-between the isomer pair. A new experimental method, which couples differential mobility spectrometry with ultraviolet photodissociation spectroscopy (DMS-UVPD), is also developed and tested. Three test cases are discussed herein. These test cases showcase new theoretical techniques for mapping and visualizing potential energy surface (PES) and finding transition state (TS) structures, as well as experimental techniques of measuring UVPD spectra of DMS-MS isolated ion populations. Introduce of structure similarity, a technique developed for unsupervised machine learning (ML), enables effective domain of mapping PESs, which may subsequently be used to interpret experimental observations for systems of high geometric complexity. The experimental DMS-UVPD technique is shown capable of isolating ion species such that UVPD spectra may be recorded for characterization of analytes of interest. For the test cases described herein, these new methods provide meaningful (sometimes anti-intuitive) directions for future work. For the structure similarity method, its PES mapping capability is tested in Chapter 3 with a collection of protonated serine dimer cations, [Ser2 + H]+ to rationalize its infrared multiphoton dissociation (IRMPD) spectrum. Eventually, the spectral carrier is assigned to a non-global minimum (GM) isomer based on the partitioning information of the PES and spectral similarity. In Chapter 4, the accompanying structural interpolation method is employed to find TSs that can rationalize a regioselective alkylation reaction between a barbituric acid derivative and an alkyl-tricarbastannatrane complex. By combining the interpolation method together with chemical intuition, a total of 3 reaction channels are found, and the regioselectivity of the alkylation is identified as a kinetic effect. In Chapter 5, an acylhydrazone (AY) derivative, a photoswitch candidate, is examined using the DMS-UVPD technique. Experimentally, the protonated [AY + H]+ cation is injected into the instrument for DMS separation and laser interrogation, while theoretically, a number of neutral and protonated isomers are sampled. Eventually, separation of the ion population is observed and attributed to some ion-solvent cluster. Four isomers are found from theoretical calculation that may account for the UVPD spectraen
dc.identifier.urihttp://hdl.handle.net/10012/16428
dc.language.isoenen
dc.pendingfalse
dc.publisherUniversity of Waterlooen
dc.subjectserine dimeren
dc.subjecttricarbastannatraneen
dc.subjectacylhydrazoneen
dc.subjectDMS-UVPDen
dc.subjectstructure similarityen
dc.subjectdissimilarity functionen
dc.subjectstructure interpolationen
dc.subjecttricarbastannatrane alkylationen
dc.subjectgas phase clustersen
dc.titleThe Structure and Properties of Weakly Bound Clustersen
dc.typeDoctoral Thesisen
uws-etd.degreeDoctor of Philosophyen
uws-etd.degree.departmentChemistryen
uws-etd.degree.disciplineChemistryen
uws-etd.degree.grantorUniversity of Waterlooen
uws.contributor.advisorHopkins, W. Scott
uws.contributor.affiliation1Faculty of Scienceen
uws.peerReviewStatusUnrevieweden
uws.published.cityWaterlooen
uws.published.countryCanadaen
uws.published.provinceOntarioen
uws.scholarLevelGraduateen
uws.typeOfResourceTexten

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