<p> A study of the Fermi surface of mercury has been carried out using cyclotron resonance and magnetoresistance techniques. Oscillations of the microwave surface impedance, which have been identified as quantum oscillations, have appeared at high magnetic field strengths, and a study of these oscillations has added more information about the Fermi surface. </p> <p> The results of these experiments are compared with two models of the Fermi surface, the nearly-free-electron model, and the relativistic-augmented-plane-wave model. The relativistic-augmented-plane-wave model was found to require only small modifications to be consistent with the data. </p> / Thesis / Doctor of Philosophy (PhD)

Duan Lifang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 83-87). / Abstracts in English and Chinese. / Title Page --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Tables --- p.vii / List of Figures --- p.viii / Symbols and Abbreviations --- p.x / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Mass spectrometry in biochemistry --- p.1 / Chapter 1.2 --- Electrospray ionization (ESI) --- p.2 / Chapter 1.3 --- Fourier transforms ion cyclotron resonance mass spectrometry (FTICR-MS) --- p.4 / Chapter 1.3.1 --- Ion motions --- p.5 / Chapter 1.3.2 --- Mass calibration --- p.7 / Chapter 1.3.3 --- Tandem mass spectrometry --- p.11 / Chapter 1.4 --- Sustained off-resonance irradiation collision-induced dissociation (SORI-CID) of peptide ions --- p.13 / Chapter 1.5 --- Outline of present work --- p.18 / Chapter CHAPTER 2 --- INSTRUMENTATION AND EXPERIMENTAL / Chapter 2.1 --- Fourier-trans form ion cyclotron resonance mass spectrometer --- p.19 / Chapter 2.1.1 --- Vacuum system --- p.19 / Chapter 2.1.2 --- Nanospray source --- p.23 / Chapter 2.1.3 --- Ion transfer system --- p.26 / Chapter 2.1.4 --- Infinity cell --- p.28 / Chapter 2.1.5 --- Data acquisition system --- p.29 / Chapter 2.2 --- Experimental --- p.29 / Chapter 2.2.1 --- Simple acquisition pulse program --- p.30 / Chapter 2.2.2 --- Tandem mass spectrometry (SORI-CID MS/MS) --- p.32 / Chapter CHAPTER 3 --- DISSOCIATION OF MODEL PEPTIDE IONS UNDER SORI-CID CONDITIONS / Chapter 3.1 --- Introduction --- p.35 / Chapter 3.2 --- Experimental --- p.37 / Chapter 3.3 --- Results and discussion --- p.41 / Chapter 3.3.1 --- "SORI-CID of XG3WG3X (where X 二 R, K and N)" --- p.41 / Chapter 3.3.2 --- SORI-CID of RGnWGnR (where n=l -5) --- p.46 / Chapter 3.3.3 --- SORI-CID of RG3XG3R (where X = D and E) --- p.48 / Chapter 3.4.4 --- SORI-CID of sequence isomers of RG5WG5R --- p.51 / Chapter 3.4 --- Conclusions --- p.56 / Chapter CHAPTER 4 --- EXACT MASS MEASUREMENTS OF THE PRODUCT IONS DERIVED FROM SORI-CID FTICR-MS / Chapter 4.1 --- Introduction --- p.57 / Chapter 4.2 --- Experimental --- p.60 / Chapter 4.3 --- Results and discussion --- p.61 / Chapter 4.3.1 --- Origin(s) of the mass measurement error --- p.63 / Chapter 4.3.2 --- Pressure effect on the cyclotron frequencies of trapped ions --- p.67 / Chapter 4.3.3 --- Modified internal lock-mass calibration method --- p.70 / Chapter 4.4 --- Conclusions --- p.79 / Chapter CHAPTER 5 --- CONCLUSIONS --- p.81 / REFERENCES --- p.83 / APPENDIX I The Proton affinity (PA) and the structural formulae of 20 α-amino acids --- p.88 / APPENDIX II Schematics of the proposed mechanisms of peptide dissociation under low-energy CID conditions --- p.89 / APPENDIX III Pulse programs for simple MS and MS/MS experiments --- p.92 / APPENDIX IV Schematics of the proposed mechanisms for the formation of y8+ ions from the singly protonated arginine- and lysine-containing peptides --- p.99

In this thesis, I present my research into the development and use of a magneto-spectrometer operating at terahertz frequencies. Molecular samples with unpaired electrons were studied using electron paramagnetic resonance (EPR) spectroscopy and the properties of semiconducting samples were measured by cyclotron resonance. A terahertz time-domain spectrometer was constructed, fine-tuned and benchmarked. The use of a large area photoconductive antenna (PCA), with a bias voltage modulated at 1 MHz, allowed for a signal-to-noise ratio of 13800:1 to be achieved, which was equal or superior to comparable systems in use. The thermal behaviour of the PCA was studied and modelled to find that a 28% increase in emission occurred when the PCA was cooled to 100 K and a 22% increase in the maximum usable bias voltage was possible when the emitter substrate was cooled in a liquid nitrogen cryostat. The spectrometer was used to study a mixed type I/type II GaAs quantum well heterostructure as a test sample, in the process extending the existing research performed on this controllable terahertz filter. Together with a Gunn diode, bolometer and a Schottky diode, a pulsed magnet was developed into a 135 GHz, continuous-wave EPR spectrometer. EPR was detected in DPPH allowing for the spectrometer magnetic field accuracy to be determined and in ruby, which provided the crystal orientation of the sample and the base temperature of the spectrometer. Following this, three novel mixed-metal fluoride-centred triangles were studied on a multiple frequency EPR spectrometer allowing for the exchange interactions to be calculated along with the g-factors for two energy states. Two dimetallic cobalt complexes were studied to find that small changes to the molecules resulted in significant changes in the measured EPR spectra and so these molecules could be a useful part of the study of exchange coupled systems. The terahertz time-domain spectrometer was then combined with the pulsed magnet and an asynchronous optical sampling (ASOPS) system. Use of ASOPS allowed the number of waveforms measurable during a magnetic field pulse to be increased by at least a factor of 20 compared to contemporary alternatives. The spectrometer was used study cyclotron resonance in a two-dimensional electron gas (2DEG) formed at a GaAs/AlGaAs interface. Cyclotron resonance was successfully measured in the 2DEG at frequencies up to 1.6 THz, finding an electron effective mass of 0.071 m e , a sheet electron density of 3.3 × 10 11 cm -2 and a mobility of 1.5 × 10 5 cm 2 V -1 s -1 . Furthermore, using this system, the detection of EPR in a ruby sample was achieved, providing the first demonstration of ASOPS being used to study EPR at terahertz frequencies.

During the course of the systematic study, it was also discovered that doubly-protonated diarginated peptides containing multiple glutamic acid residues (E) (n>4) could suppress the backbone fragmentation of [M+2H]+&middot; . Together with the results obtained from conformational searches, it was hypothesized that the interactions between carboxylic oxygens of E side chains and backbone amide hydrogens could stabilize the radical intermediate and thereby inhibiting the usual N-Calpha cleavages and H &middot; loss from [M+2H]+&middot;. / In order to ascertain the impacts of the structural features of polypeptide and oligosaccharide ions on the dissociation of these biomolecules under typical collision induced dissociation (CID) and electron capture dissociation (ECD) conditions, the dissociation patterns of even-electron precursor ions generated by protonation ([M+nH]n+)/metalation ([Metal+M]n+), odd-electron hydrogen-deficient precursor ions (M+&middot;) generated by SORI-CID of [Cu(Tpy)M]2+ and odd-electron hydrogen-surplus precursor ions ([M+2H]+&middot;) generated by ECD of [M+2H] 2+ were examined. It was found that backbone cleavages, with the generation of b/y and c/z ions, were dominant in the dissociation of [M+H]+ and [M+2H]+&middot; respectively. Whilst in the dissociation of M+&middot;, side chain loss reactions were the major fragments generated. For post translational modification (PTM)-containing peptides, the labile PTM groups were found to cleave preferentially in the dissociation of M+&middot; and [M+H]+, but were found to be retained in the intact peptides and peptide fragments in the dissociation of [M+2H]+&middot;. It is hypothesized that the different dissociation pathways is attributed to the different nature of radicals. Further to these, it was found that in the dissociation of oligosaccharides, similar cleavage patterns (glycosidic and cross-ring cleavages) were obtained regardless of the nature of the precursor ions (i.e. whether odd- or even-electron) and the ion activation conditions. / Chan, Wai Yi. / Adviser: T.W. Dominic Chan. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 145-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Lim Che Lau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 79-84). / Title Page --- p.i / Table of Contents --- p.ii / List of Tables --- p.iv / List of Figures --- p.v / List of Schemes --- p.vii / Acknowledgments --- p.viii / Abstract --- p.ix / Chapter CHAPTER 1: --- INTRODUCTION / Chapter 1.1. --- Historical Background --- p.1 / Chapter 1.2. --- FTICR with External Ion Source --- p.2 / Chapter 1.3. --- High Mass Analysis in FTICR --- p.4 / Chapter 1.4. --- Outline of Present Work --- p.7 / Chapter CHAPTER 2: --- INSTRUMENTATION AND EXPERIMENTAL / Chapter 2.1. --- Instrumentation --- p.8 / Chapter 2.1.1 --- Ion Source --- p.10 / Chapter 2.1.1.1. --- Liquid Secondary Ion Mass Spectrometry --- p.11 / Chapter 2.1.1.2. --- Electrospray Ionization --- p.12 / Chapter 2.1.2. --- Electrostatic Ion Focusing System --- p.15 / Chapter 2.1.3. --- ICR Analyzer Cell and Magnet --- p.18 / Chapter 2.1.4. --- Data Acquisition and Handling System --- p.22 / Chapter 2.2. --- Experimental --- p.22 / Chapter 2.2.1. --- Liquid Secondary Ion Mass Spectrometry --- p.22 / Chapter 2.2.2. --- Electrospray Ionization --- p.23 / Chapter 2.2.3. --- Nozzle-Skimmer Dissociation --- p.24 / Chapter 2.2.4. --- Sustained Off-Resonance Irradiation Collision- Induced Dissociation --- p.24 / Chapter 2.2.5. --- Data Acquisition and Processing --- p.27 / Chapter 2.2.6. --- Mass Calibration --- p.27 / Chapter CHAPTER 3: --- STRUCTURAL CHARACTERIZATION OF TERPYRIDINE-BASED POLYETHER DENDRIMERS AND THEIR IRON(II) METALLOCOMPLEXES BY LIQUID SECONDARY ION MASS SPECTROMETRY AND ELECTROSPRAY IONIZATION MASS SPECTROMETRY / Chapter 3.1. --- Introduction --- p.28 / Chapter 3.2. --- Sample Preparation --- p.29 / Chapter 3.3. --- Results and Discussion --- p.30 / Chapter 3.3.1. --- Liquid Secondary Ion Mass Spectrometry Studies --- p.30 / Chapter 3.3.1.1. --- Dendrimers --- p.30 / Chapter 3.3.1.2. --- Metallodendrimers --- p.41 / Chapter 3.3.2. --- Electrospray Ionization Mass Spectrometry Studies --- p.47 / Chapter 3.4. --- Conclusions --- p.53 / Chapter CHAPTER 4: --- STUDIES OF LANTHANIDE(III) PORPHYRIN- PHTHALOCYANINE HETEROLEPTIC SANDWICH COMPLEXES USING ELECTROSPRAY IONIZATION / Chapter 4.1. --- Introduction --- p.54 / Chapter 4.2. --- Results and Discussion --- p.55 / Chapter 4.2.1. --- Molecular Weight Determination --- p.57 / Chapter 4.2.2. --- Structural Elucidation --- p.65 / Chapter 4.2.3. --- Charge-Transfer Processes --- p.72 / Chapter 4.3. --- Conclusions --- p.76 / Chapter CHAPTER 5: --- CONCLUSIONS --- p.77 / References --- p.79

Thesis (Ph. D.)--Washington State University, December 2007. / Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, June 1997. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Not available / text

The first part of this thesis is a study of thermally activated conduction, Hall effect, and Far-Infrared absorption in n-InP. Accurate measurements of threshold energies are deduced from the temperature dependence of these effects, after correction for Fermi level variations, and it is shown that the threshold for electrical conduction is higher than for Hall effect, or cyclotron resonance. An explanation is given in terms of the long range impurity potential fluctuations. The second part of this thesis presents measurements of the thermopower in heterostructures for the GaInAs - InP, GaInAs - InAlAs, and GaAs - GaAlAs systems, with and without magnetic field, for temperature varying from 2K to 10K. In high magnetic fields, strong oscillations of the thermopower are seen, with the same phase as the Shubnikov - de Haas oscillations in the resistivity, in accordance with theory. The magnitude and temperature dependence of the thermopower are mostly as predicted for the superlattice but those of the heterojunctions disagree with the predictions. A discussion of the cause of this disagreement is given. In the final part, the value of the relative energy shift between different valleys of the conduction band of a thin film of PbTe grown on BaF₂ is obtained. This will be used to obtain the deformation potential of PbTe.