This research work focused on studying the emission spectroscopy produced from the high energy ion-molecule collision processes in mass spectrometry. The collision experiments are described and divided into 4 chapters (Chapter 3, 4, 5, 6).N2O+● is an ion of atmospheric importance. In chapter 3 the investigation of the collision between high translational energy (4-8 keV range) N2O+● ions and Helium target gas in mass spectrometry using collision induced emission (CIE) spectroscopy is described.In chapter 4, the collision-induced emission (CIE) spectra from 4-8 keV collisions between projectile He+● ions and CO2 target gas (He+●/CO2) were obtained. In Chapter 5, to probe the validity of this hypothesis, CIE experiments were carried out to observe the photon emissions from keV collisions of a selection of projectile ions with O2 target gas. By studying the resulting CIE spectra, a second potential mechanism came to light, one that involves the nearly isoenergetic O2+. A → X state transition. In chapter 6, neutral hydroxymethylene and formaldehyde were generated by charge exchange neutralization of their respective ionic counterparts and then were reionized and detected as recovery signals in neutralization-reionization mass spectrometry in the modified VG-ZAB mass spectrometer.

Nuclear power currently plays a significant role in today’s balanced energy portfolio. However, with this expansion, comes the need for improved methods to characterise and manage radioactive wastes arising from fission activities throughout the fuel cycle, and the need for fundamental research into all aspects of the nuclear fuel cycle. Whilst the chemistry of actinides is enjoying a renaissance, in particular the study of unusual oxidation states which were previously unobtainable, many fundamental properties of the actinides remain unknown. This thesis explores the coordination chemistry and emission spectroscopy of a selection of actinides (U to Cm) with a view to accessing the unstable f 1 oxidation states of uranium and neptunium. In particular, the role of cation-cation interactions (CCIs) on the stability, redox and spectroscopic properties has been addressed. Work on the luminescence of uranyl(VI) complexes has led to an increased understanding of the non-aqueous solution behaviour of the actinyl ion, in particular by fingerprinting/identifying complexes bearing cation-cation interactions. The uranyl(VI) LMCT emission profiles are observed to significantly red shift when CCIs are present, accompanied by a drastic reduction in the radiative lifetime. These observations have been supported by the increasingly effective diffusion-ordered nuclear magnetic resonance technique. This leads to the conclusion that uranyl(VI) cation-cation interactions unsupported by bridging ligands are unstable in solution. Attempts to isolate stable uranyl(V) complexes of tetraphenylimidodiphosphinate (TPIP) and the fluorinated acacs have proved difficult. The TPIP ligand has shown an unprecedented preference to stabilise NpO2(VI). From these observations, it has been possible to conclude that TPIP has a strong preference for the actinyl(VI) oxidation states. A preliminary study on the minor actinides Am and Cm in the +III oxidation state has taken place and allowed preliminary comparisons between a novel series of bis-trialkylsilyl bipyridyl and phenanthroline ligands, which have been designed in an attempt to study the effect of steric bulk in supporting unusual oxidation states of the actinides. An initial study of these ligands with AnO2(V) and AnO2(VI) (An = U and Np) has also taken place.

The utility of multivariate analysis methods for the qualitative and quantitative analysis of complex ICP optical emission spectra is shown. A photodiode array is used to collect data which are simplified to a low resolution (approx. 4 A) spectrum for a number of knowns and unknowns. The digitized spectra thus obtained are plotted as points in multivariate space (pattern space). The spectra of different elements appear in well defined regions of pattern space. Qualitative analysis is accomplished by methods of cluster analysis and factor analysis. Quantitative analysis is carried out using multidimensional working curves. The pattern space coordinate system is transformed to give axes corresponding directly to elemental concentrations, allowing direct simultaneous determination of elemental composition. The effect of line intensities, detector dynamic range, and matrix effects are also discussed. / Science, Faculty of / Chemistry, Department of / Graduate

This work presents an analytic three dimensional image reconstruction algorithm that was developed for a proposed volume-imaging PET scanner. The development of the algorithm was motivated by the scanner's ability to collect an order of magnitude more data than current PET systems and the lack of an efficient algorithm that could use the extra data. The algorithm is based on an extension of the Recovery Operator of Orlov[68] and operates by convolution in object space. This method of operation sets it apart from other analytic direct image reconstruction algorithms that rely on Fourier transforms. The algorithm is tested with ideal data and parameters that are appropriate to the new PET scanner. The results of the test show that the algorithm behaves as expected except for a 17% overshoot in the reconstructed value in one area. An explanation of this artifact is suggested, although not verified. Finally, the efficacy of the algorithm is demonstrated by proving that it is functionally equivalent to Fourier transform methods. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Acoustic Emission Analysis (AEA) is the study of the sonic (and ultrasonic) energy released by chemical systems in the form of transient waves, as the system attempts to (re)attain equilibrium. This area of chemistry, and chemical analysis, is ripe for fundamental studies since it has been little explored. The high potential of the technique as a non-invasive, non-destructive reaction monitoring scheme suggests that numerous applications will follow. In this work, an apparatus and software have been constructed to monitor acoustic emission (AE) and collect and process AE data. A broad-band piezoelectric transducer was used to convert the acoustic signals to electrical waveforms which could be captured by a digital storage oscilloscope. These waveforms were then stored on an IBM-compatible computer for further analysis. Analysis of the data was performed using pattern recognition techniques. The signals were characterized through the use of descriptors which can map each signal onto a multi-dimensional feature space. Visualization of the data structure in multidimensional space was accomplished using several methods. Hierarchical clustering was used to produce tree structures, known as dendrograms, which attempt to show clustering of the signals into various groups. Abstract factor analysis (AFA) - also called principal components analysis (PCA) - was used to project the data onto a two dimensional factor space to allow for direct viewing of structure in the multidimensional data. Sodium hydroxide dissolution, aluminum chloride hydration and heat activation of Intumescent Flame Retardants (IFR's) were used to test the assembled hardware and to provide data to submit to the pattern recognition algorithms coded as part of this work. The solid-solid phase transition of trimethylolethane (Trimet), and the liquid crystal phase transitions of two liquid crystals (α-ѡ-bis(4-n-decylaniline-benzilidene-4'-oxyhexane), and 4-n-pentyloxybenzylidene-4'-n-heptylaniline) were also monitored and the signals analyzed. The pattern recognition software was able to extract much information from the acoustically emitting samples - information which would not have been apparent by using standard (uni- and bi-variate) methods of analysis. Chemical acoustic emission, coupled with pattern recognition analysis, will be able to provide the chemist with knowledge (qualitative, quantitative, kinetic, etc.) about chemical systems which are often difficult or impossible to monitor and analyze by other means. / Science, Faculty of / Chemistry, Department of / Graduate

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The Gemini Near Infrared Spectrograph - Distant Quasar Survey (GNIRS-DQS) is the largest uniform, homogeneous survey of its kind, covering 260 quasars at 1.5 ≤ z ≤ 3.5. This unique survey, coupled with data from the Sloan Digital Sky Survey (SDSS), enables new investigations into redshifts, supermassive black hole masses (MBH), and accretion rates at high redshift through spectroscopic coverage of important rest-frame UV-optical emission lines. The importance of this survey is highlighted in the fact that the optical emission lines provide more reliable measurements of these quasar parameters than their UV counterpart. With such a unique sample compiled here, I construct prescriptions to calibrate these quasar parameters derived from rest-frame UV emission lines to those derived from rest-frame optical emission lines. These prescriptions provide important insight into how these parameters depend on redshift and are potentially biased as we look out further into the universe. Additionally, all the work completed with this sample will help shape our understanding of how these quasars and their host galaxies co-evolve over cosmic time.

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