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This work sets out a framework to provide a metrological basis for static SIMS measurements. This surface analytical technique has been is use for over thirty years but, because of the lack of an infrastructure, has not achieved its full potential in industry. To build this basis, the measurement chain is studied from the sample through to the detector and data processing. By understanding the effects of each link in the chain, repeatabilities are reduced by orders of magnitude to below 1%, the ion beam current and flux density are calibrated to better than 2%, ion beam damage in polymers is controlled and detection efficiencies calculated. Utilising these developments, a characterised and calibrated SIMS spectrometer is used to establish reference materials. An inter-laboratory study to assess the extent of spectrum variability between spectrometers was conducted involving over twenty laboratories worldwide. Analysis of the data gives the level of repeatability and reproducibility using current procedures. Repeatabilities for some laboratories are as good as 1% but many are at 10% and a few as poor as 80%. A Relative Instrument Spectral Response, RISR, is developed to facilitate the comparison of spectra from one instrument to another or library data. For most instruments reproducibilities of 14% are achievable. Additionally, the wide variety of ion beam sources and energies, presently in use, result in spectra that are only broadly comparable. A detailed study of these effects provides, for the first time, a unified method to relate the behaviour for all ion species and energies. A development of this work gives a totally new spectroscopy, known as G-SIMS or gentle-SIMS. Here, the static SIMS spectrum for a low surface plasma temperature is calculated which promotes those spectral intensities truly representative of the analysed material and reduces those caused by additional fragmentation and rearrangement mechanisms. The resulting GSIMS spectra are easier to identify and are interpreted more directly. This work provides the essential basis for the development of static SIMS. Future work will improve the consistency of library data so that the valid data for molecular identification can be uniquely extracted. The measurement base will be developed to meet the growing requirements for static SIMS analysis of complex organic and biomaterials.

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<p> The preparation of compounds containing polyatomic cations of sulphur, selenium and tellurium has been investigated by using oxidising agents such as AsF5, SbF5, S2O6F2 and SO3. New compounds, containing polyatomic cations Se8 2+, Se4 2+, Te3n n+, Te4 2+ Ten n+, S16 2+, S8 2+ and S4 2+, and anions of very strong acids such as Sb2F11- and AsF6- were isolated and characterised by a combination of the stoichiometry of the preparation reactions, UV-visible spectrophotometry, Infrared and Raman spectroscopy and magnetic susceptibility measurements.</p> <p> Solutions of sulphur in various concentrations of oleum were investigated in detail by UV-visible spectrophotometry and e.s.r. spectroscopy. Evidence is presented for the formation of the sulphur cations S16 2+, S8 2+ and S4 2+ in these media, and for the presence of low concentrations of the radical cations S8+ and S4+.</p> / Thesis / Doctor of Philosophy (PhD)

Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions. It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a projectile for SIMS. The secondary ion yields (i.e., the number of secondary ions detected per projectile impact) from impacts of 10-26 keV C24H12+, C60+, gramicidin S+ and C60F40+ projectiles were examined to compare the effectiveness of the projectiles. The [M-H]- secondary ion yields from several organic samples varied inversely with the molecular weight. Multiple ion emission decreases monotonically as a function of the number of secondary ions emitted per impact and varies with impact energy such that higher energies produce more multiple ion emission. The emission of CN- from biological samples as a function of carbon-based projectile characteristics was examined to explore the possibility of using CN- as a molecular identifier. CN- emission was found to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic energy, and a second in which the F atoms deposited most of the initial kinetic energy into the surface before being ejected. The [M-H]- secondary ion yield of gramicidin S was increased ~ 15 times by embedding the analyte in a matrix of sinapic acid. These results show the optimum carbon based projectile for a given sample is dependent upon the signal to be monitored from the surface. The results also show CN- has potential as a molecular identifier. Additionally, the detection of re-emitted F- confirms prior predictions of re-emitted projectile atoms.

Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions. It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a projectile for SIMS. The secondary ion yields (i.e., the number of secondary ions detected per projectile impact) from impacts of 10-26 keV C24H12+, C60+, gramicidin S+ and C60F40+ projectiles were examined to compare the effectiveness of the projectiles. The [M-H]- secondary ion yields from several organic samples varied inversely with the molecular weight. Multiple ion emission decreases monotonically as a function of the number of secondary ions emitted per impact and varies with impact energy such that higher energies produce more multiple ion emission. The emission of CN- from biological samples as a function of carbon-based projectile characteristics was examined to explore the possibility of using CN- as a molecular identifier. CN- emission was found to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic energy, and a second in which the F atoms deposited most of the initial kinetic energy into the surface before being ejected. The [M-H]- secondary ion yield of gramicidin S was increased ~ 15 times by embedding the analyte in a matrix of sinapic acid. These results show the optimum carbon based projectile for a given sample is dependent upon the signal to be monitored from the surface. The results also show CN- has potential as a molecular identifier. Additionally, the detection of re-emitted F- confirms prior predictions of re-emitted projectile atoms.

In the study of kinetic theory and especially in the study of rarefied gas dynamics one often turns to the Boltzmann equation. The mathematical theory developed by Ludwig Boltzmann was at first sight applicable in aerospace engineering and fluid mechanics. As of today, the methods in kinetic theory are extended to other fields, for instance, molecular biology and socioeconomics, which makes the need of finding efficient solution methods still important. In this thesis, we study the underlying theory of the continuous and discrete Boltzmann equation for monatomic gases. We extend the theory where needed, such that, we cover the case of colliding molecules that possess different levels of internal energy. Mainly, we discuss discrete velocity models and present explicit calculations for a model of a gas consisting of polyatomic molecules modelled with two levels of internal energy. / I studiet av kinetisk teori och speciellt i studiet av dynamik för tunna gaser vänder man sig ofta till Boltzmannekvationen. Den matematiska teorien utvecklad av Ludwig Boltzmann var vid första anblicken tillämpbar i flyg- och rymdteknik och strömningsmekanik. Idag generaliseras metoder i kinetisk teori till andra områden, till exempel inom molekylärbiologi och socioekonomi, vilket gör att vi har ett fortsatt behov av att finna effektiva lösningsmetoder. Vi studerar i denna uppsats den underliggande teorin av den kontinuerliga och diskreta Boltzmannekvationen för monatomiska gaser. Vi utvidgar teorin där det behövs för att täcka fallet då kolliderande molekyler innehar olika nivåer av intern energi. Vi diskuterar huvudsakligen diskreta hastighetsmodeller och presenterar explicita beräkningar för en modell av en gas bestående av polyatomiska molekyler modellerad med två lägen av intern energi.

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<p> In a study of the structures of some polyatomic cations of Group VI and VII, the compound Se4(HS2O7)2 has been prepared and its structure determined by single crystal X-ray diffraction. The bonding in the square planar cation has been discussed in terms of molecular orbital and valence bond theory. The anion geometry has been discussed and simple rules proposed to predict the changes which occur in bond length and bond angle when one or more oxygen in an SO4 tetrahedron is bonded to another atom or group.</p> <p> A θ/θ vertical diffractometer has been constructed, and computer programmes written, so that cation structures could be determined in solution. The structures of the Se4 2+ and Te4 2+ cations have been determined in fluorosulphuric acid, and are shown to be square planar.</p> <p> Liquid diffraction studies of 3:1, I2/S2O6F2 solutions have shown the presence of a cation containing a linear chain of three iodine atoms.</p> / Thesis / Doctor of Philosophy (PhD)