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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

A photophysical study of novel silicon and zinc phthalocyanines

FitzGerald, Simon January 2002 (has links)
Phthalocyanines are an important class of compounds with many commercial applications. The core macrocycle is chemically robust, such that a wide variety of substituted species with interesting properties can be synthesised. The work reported in this thesis represents a detailed photophysical study of both known and novel substituted silicon and zinc phthalocyanines.The behaviour of tetrasulfonated zinc phthalocyaniae (ZnPcS(_4)) in aqueous acetonitrile is investigated. This work shows the sensitivity of ZnPcS(_4) to pH, caused by protonation of the phthalocyanine on the bridging azomethine nitrogen atoms. The spectral perturbation that results includes red shifted absorption and emission bands, with a reduced fluorescence lifetime relative to the unprotonated species. AxiaUy substituted silicon phthalocyanines functionalised through bis-esters have highly resolved spectral features due to reduced ring interactions, whilst the light core atom results in excellent fluorescence quantum yields and lifetimes. Electron rich axial substituents (in this case methoxybenzenes) cause quenching of the phthalocyanine fluorescence through an electron transfer mechanism, and the extent of quenching is related to both the oxidation potential of the quencher and the chain length/flexibility. A number of silicon phthalocyanines with tetrathiafulvalene (TTF) containing substituents are also investigated. TTF is known to quench phthalocyanine fluorescence very efficiently, but this current work shows that the degree of quenching is strongly distance dependent. The oxidation potential of TTF is low, and this allows the selective electrochemical oxidation of TTF without affecting the phdialocyanine. It is shown that such oxidation causes a reversal of the electron transfer mechanism. The phenomenon of fluorescent dimers in phthalocyanine chemistry is rarely observed, and most reports arise from spectral and experimental artefacts. However a solketal substituted zinc phthalocyanine and some of its derivatives are conclusively shown to demonstrate this behaviour. At low temperature a broadened absorption profile is observed, with new emission centred at ~750 nm - such spectral behaviour agrees with Exciton Theory for a clamshell dimer. Flash photolysis studies at intermediate temperatures highlights the dynamic nature of the dimer species - absorption of a photon results in the separation of the dimer, followed by fast recombination.
52

Microwave emission from indium antimonide

McDonnell, Thomas Peter January 1971 (has links)
129 leaves : ill. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1972) from the Dept. of Physics, University of Adelaide
53

Helicon propagation in indium antimonide /

Trethewie, John Vere. January 1972 (has links) (PDF)
Thesis (M.Sc.) -- University of Adelaide, Dept. of Physics, 1973.
54

Emission spectroscopy of long pulse relativistic electron beam-produced argon plasmas

Repetti, Thomas Edward. January 1987 (has links)
Thesis (M.S.)--University of Michigan, 1987.
55

Submillimeter wave absorption spectroscopy in the free jet environment

Melnik, Dmitry Georgievich, January 2003 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xxv, 475 p.; also includes graphics Includes bibliographical references (p. 469-475). Available online via OhioLINK's ETD Center
56

Measurements of depolarization factors in Raman spectroscopy

Lyons, Philip Augustine, January 1948 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1948. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves i-iii).
57

Application of photoacoustic techniques to solid and liquid materials /

Aravind, Manju. January 1994 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 137-140).
58

Laser Raman spectroscopy of adsorbed species pyridine and n-butenes on silica gel /

Schrader, Glenn LaRue, January 1976 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 170-175).
59

Vibrational spectroscopies of bismuth molybdate catalysts

Kovats, William Daniel. January 1984 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 338-345).
60

Fluorescent probes in the solid state and their application to inorganic ion determinations

Johnston, Murray Vincent. January 1980 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 344-347).

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