Photoelectron spectroscopy is the study of the kinetic energies of the photoelectrons ejected from gaseous species by monochromatic radiation. Subtraction of these kinetic energies from the incident photon energy yields the binding energies of the orbitals from which the electrons were removed. The work to be described falls into two main parts. The first is concerned with the development of a new type of spectrometer to measure such kinetic energies. To date, all photoelectron spectrometers designed specifically for gaseous samples have employed a retarding field of cylindrical geometry to energy-analyze the emitted photoelectrons. Consideration of the angular distribution with which electrons are ejected during the photoionization process indicates that a spectrometer utilizing a retarding field of spherical geometry should give a stopping curve, the first differential of which is close to the true photoelectron kinetic energy spectrum. Instruments of both cylindrical and spherical geometry were constructed and their properties tested. Conclusive evidence for the superiority of the spherical system is presented together with details of its construction and operation. The second part of this thesis/contains the results of photoelectron spectroscopic studies on twenty-one atoms and molecules (Ar, Kr, Xe, H₂, HD, D₂, N₂, CO, O₂, NO, HF, HCl , HBr, HI, F₂, Cl₂, Br₂, I₂,N₂O, NO₂ and NH₃). The energies of the ionic states could be obtained to a precision of 0.01 ev., and they agree, well with available spectroscopic data. In many instances new ionic states are found, and where possible they are correlated with states predicted by molecular orbital theory. Relative transition probabilities to the various ionic states are also obtained by this method. They are, in nearly every case, the only experimental values available. The spacings and relative probabilities for formation of ionic vibrational levels have been measured for certain states in H₂, HD, D₂, N₂, CO, O₂, NO, F₂, N₂O and NO₂ and the values obtained compared with spectroscopic and calculated data where this is available. / Science, Faculty of / Chemistry, Department of / Graduate

The photolysis of azomethane, di-isopropyl ketone and azoisobutane has been examined briefly in the gas phase and these compounds have been found to be convenient sources of the methyl, isopropyl and tert-butyl radicals respectively. The photolysis of the mixed vapours of cyclohexadiene-1,4 with each of azomethane, di-isopropyl ketone and azoisobutane has been examined over a series of temperatures. These studies afforded the Arrhenius parameters for the abstraction of the methylenic hydrogen atom from cyclohexadiene-1,4 by the methyl, isopropyl and tert-butyl radicals. There was found no significant difference in the reactivities of these radicals towards the cyclohexadiene-1,4 substrate. The rate constants measured were [formula omitted]. The cyclohexadienyl radical is generated in this metathetical reaction, and the interaction of the cyclohexadienyl radical with the various mentioned initiator radicals was examined kinetically. It was found that the interaction of alkyl radicals with the cyclohexadienyl radical produced either benzene and the hydrocarbon, RH, (disproportionation) or 1-alkylcyclohexadiene-2,4 (combination, I) or 1-alkylcyclohexadiene-2,5 (combination, II). The ratio of the rates of formation of the two combination products (I/II) has been found to have the constant value 0.77 ± 0.17 within the experimental error for all the alkyl radicals studied. The ratio of the rate of disproportionation to the combined rates of combination was found to vary systematically over the values 0.27 ± 0.07, 0.52 ± 0.09, and 1.33 ± 0.24 for the methyl, isopropyl and tert-butyl radicals respectively. A previous study of the ethyl radical's reactions with the cyclohexadienyl radical in this laboratory had shown that this ratio for the ethyl radical was 0.38 ± 0.03. The measured values of the termination rate ratios for the various systems are consistent with the expectation that the product of greater entropy should form preferrentially and the results are considered to support the disproportionation transition state model of Bradley and Rabinovitch. During the photolysis of azomethane-cyclohexadiene-1,4 mixtures at lower intensisties, there was observed the formation of cyclohexene and greater than the expected amount of benzene. This was considered to arise from the decomposition reaction C₆H₇→C₆H₆ + H˙. Kinetic analysis of this system has afforded an estimate of the heat of formation of the cyclohexadienyl radical, (45 ± 5 kcal./mole), and consequently of its resonance energy, (24 ± 5 kcal./mole). This has been considered to be evidence that there is an interaction of the delocalized system across the methylenic carbon bridge, since the resonance energy is substantially greater than that measured in another laboratory for the straight chain pentadienyl radical (15.5 kcal./mole). The reactions of the isopropyl radical with the cyclohexadiene-1,3 molecule have been studied in the gas phase. The isopropyl radical adds to the unsaturated linkages with a rate constant [formula omitted]. The abstraction of a methylenic hydrogen atom procedes with a rate governed by the rate constant [formula omitted]. Thus the metathetical reaction procedes more slowly for the conjugated cyclohexadiene than for the unconjugated system by a factor of 1.9 at 100°. This behavior was also found for the reactions of the ethyl radical with the cyclohexadiene isomers in a previous study, and probably arises from a slightly lower free energy of the cyclohexadiene-1,3 molecule. The ratio of addition to abstraction between isopropyl and cyclohexadiene-1,3 is low, (4.3 at 100°) and degradative chain transfer has been suggested as the reason for the very low tendency of the cyclohexadiene-1,3 molecule to polymerize under homogeneous, free radical conditions. / Science, Faculty of / Chemistry, Department of / Graduate

A significant improvement in magnetic probe measurements has been achieved by developing a 3-coil magnetic probe which partially corrects for the boundary error, i.e. for the error caused by an exclusion of the plasma current from the space occupied by the probe. The spatial resolution C of the three coil probe is roughly one-half of the probe radius, a. For current distributions which vary slowly with distance (scale length, ƛ ) it is shown that the fractional error in the magnetic field is 0.2 (C/ ƛ)². For a conventional probe the error is at least four times as large. Also it has been shown that spurious signals arising from poor probe geometry (and which often obscure the signals produced by the measured magnetic fields themselves) can be eliminated by making use of the symmetry of the discharge fields. Measurements have been made on a Z-pinch discharge which confirm the claimed 3-coil probe performance by revealing a "fine" structure of the current distribution in helium in the filling pressure range 0.5 to 4 Torr. The measurements are presented in the form of a catalogue of the spatial distribution of magnetic field and the current density for a Z-pinch discharge in He and Ar. Using the probe measurements a qualitative model of the collapse of the current sheet for 4 Torr in He is developed which differs from previous models. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Some equilibrium and non-equilibrium properties of a gas of hard spheres with a long range attractive potential are investigated by considering the properties of an equation, proposed by deSobrino (1967), for a one-particle distribution function for the gas model considered. The solutions of this equation obey an H-theorem indicating that our gas model approaches local equilibrium. Equilibrium solutions of the kinetic equation are studied; they satisfy an equation for the density η(r) for which space dependent solutions exist and correspond to a mixture of gas and liquid phases. The kinetic equation is next linearized and the linearized equation is applied to the study of the stability of the uniform density stationary states of a Van der Waals gas. A brief asymptotic analysis of sound propagation in dilute gases is presented in view of introducing an approximation of the linearized Boltzmann collision integral due to Gross and Jackson (1959). To first order, the dispersion in the speed of sound at low frequencies is the same as the Burnett and Wang Chang-Uhlenbeck values while the absorption of sound is slightly less than the Burnett value and slightly greater than the Wang Chang-Uhlenbeck value; all three are in good agreement with experiment. Finally, using the method developed in the previous section, an approximation for the linearized Enskog collision integral is obtained; a dispersion relation is derived and used to show that the uniform density states which correspond to local minima of the free energy and traditionally called metastable, are in fact stable against sufficiently small perturbations. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The mantle is the largest reservoir of many of the Earth’s volatile species. Detailed isotopic studies of noble gases within the mantle volatiles have demonstrated that they are of a primordial origin, which have been trapped in the mantle since the Earth’s accretion. This original volatile signature has continually evolved over time, due to the production of in situ radiogenic isotopes and through the recycling of surface volatiles back into the mantle (Lupton and Craig, 1975; Holland and Ballentine, 2006). The study of noble gases within magmatic samples has enabled the composition and structure of the mantle to be determined and has distinguished the multiple volatile reservoirs (primordial, crustal, marine etc.) that have contributed to the mantle composition sampled. Together with the halogens (Cl, Br and I) they represent key tracers of volatile transport processes in the Earth. Therefore a combined analytical approach including the halogens and noble gases is not only be able to track the influx of surface volatile into the mantle, but also provide a greater understanding to the fundamental controls of transport, storage and partitioning of volatiles within the mantle. A combined noble gas and halogen study was undertaken on three different geological samples sets to determine how surface volatiles interact with the mantle on a variety of different scales. Firstly continental xenoliths from the Western Antarctic Rift were analysed to establish the role of subduction volatiles in the creation of the rifts volcanic products. The xenoliths have 3He/4He ratios of 7.5RA indicating that the rift is dominated by the rising asthenospheric mantle. However the Br/Cl and I/Cl ratio and heavy noble gases within the xenoliths indicate that marine derived volatiles have been incorporated into the mantle beneath the rift and may have provided and fundamental control on the formation of the rift itself. Secondly the role of surface contamination on mantle samples has been evaluated. A transect along a MOR pillow basalt has been analysed for its halogen concentrations in conjunction with the previously determined noble gases. The outer sections are enriched in Cl relative to Br and I due to the assimilation of a high salinity brine during eruption. In contrast the crystalline interior of the pillow has MORB like Br/Cl and I/Cl ratios but elevated 132Xe/36Ar ratios indicative of the incorporation of pelagic sediments. This small scale analytical approach has shown that submarine pillow basalts are prone to contamination from the surrounding marine environment and provides a method for the identification and quantification of marine contamination. Finally the halogens within olivine phenocrysts from three Emperor Seamounts have been analysed to determine the distribution of the halogens within the lower mantle. The I/Cl ratio of the samples evolves from a MORB-like ratio in the oldest seamount to elevated values similar to sedimentary pore fluids and chondrites in the younger seamounts. This indicates that the Hawaiian mantle plume contains isolated pockets of subducted or primordial material which have been isolated from whole mantle mixing and have therefore retained a halogen signature distinct from the average mantle values.

No description available.

Orientador: Paulo Hiroshi Sakamaka / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-16T06:37:40Z (GMT). No. of bitstreams: 1 Scheid_VladimirHenriqueBaggio_M.pdf: 2893669 bytes, checksum: 1ea697b502ac6afff4ced927410d7bfc (MD5) Previous issue date: 1986 / Resumo: Este trabalho experimental foi dedicado ao estudo das propriedades macroscópicas de um plasma não homogêneo c anisotrópico. Com este objetivo foi construída uma máquina linear de espelho magnético na qual o plasma era produzido na forma de uma coluna cilíndrica por rádio freqüência (RF). As medidas das propriedades macroscópicas do plasma foram levantadas basicamente com o uso das sondas de Langmuir, Hall e magnética. Os resultados experimentais obtidos são discutidos, analisados e comparados com os que foram fornecidos pelo modelo teórico proposto para representar o tensor de permissividade dielétrica do plasma. Estes resultados Indicam que o plasma magnetizado possui propriedades não lineares e anisotrópicas, propriedades estas que se apresentam de forma não homogênea ao longo da coluna de plasma / Abstract: Not informed. / Mestrado / Física / Mestre em Física

Orientador: Paulo Hiroshi Sakanaka / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-16T22:53:19Z (GMT). No. of bitstreams: 1 Shigueoka_Yoshyuki_M.pdf: 1772625 bytes, checksum: 12a5ca824a2d8d727ded428b94802f37 (MD5) Previous issue date: 1979 / Resumo: Foi desenvolvido um modelo de 1 + zero dimensões, borda abrupta na direção r e uma dimensão na direção z, para estudar a dinâmica do q - pinch, com o campo de polarização. Verificou-se que o efeito do raio do plasma sobre a descarga é apreciável, podendo até inverter o sinal do dBz/dt. A influência do fato do solenôide ser de tamanho finito se manifesta como oscilação de grandezas como Bz, R, Ti, etc. ao longo do eixo z. Estas oscilações são as oscilações transpostas de bounce e não constituem nenhuma instabilidade nova / Abstract: It has been developed a (1 + zero) D model, sharp boundary in r and 1D in z, to study dynarnics e - pinches with bias field, in order to calculate bounce oscilations, plasma temperature, effects of plasma radius on the discharge and the influence of finiteness of the q- pinch coil length on the bounce oscilations. It was observed that the effect of plasma radius variation on discharge is appreciable. It can even invert the sign of dBz/dt. The influence of the finite length coil manifested through oscillations of quantities; such as, Bz, R, Ti and Bi along z axis. These oscillations are z simply bounce oscillations transformed into oscillations in z direction, and do not mean a new instability / Mestrado / Física / Mestre em Física

Orientadores : Arnaldo Siqueira, Jose Lopes de Faria / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-07-16T22:50:14Z (GMT). No. of bitstreams: 1 Palhares_FortunatoAntonioBadan_D.pdf: 5574433 bytes, checksum: 7f7fdfd98475bb02ca63a54505cd9727 (MD5) Previous issue date: 1985 / Resumo: O presente trabalho analisa as várias formas de ação e os vários tipos de Bombas de Gás Lacrimogenio (B.G.L) utilizadas no Brasil, em relação ao ser humano...Observação: O resumo, na integra, podera ser visualizado no texto completo da tese digital / Abstract: Not informed / Doutorado / Doutor em Anatomia Patologica

Orientador: Paulo Hiroshi Sakanaka / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-17T03:36:19Z (GMT). No. of bitstreams: 1 Mania_AntonioJamil_M.pdf: 1236088 bytes, checksum: 59569320c15a472398604a60be7e5ae1 (MD5) Previous issue date: 1989 / Resumo: Propomos o estudo da evolução de Configurações de Campo Reverso (FRCs) empregando a teoria Grad-Hogan. Das propriedades da simetria destas configurações é possível obter uma equação geral para plasmas difundindo-se lentamente. Supondo que a temperatura seja uniforme mas dependente do tempo, pode ser mostrado que a evolução é descrita como uma seqüência contínua de estados de equilíbrio, satisfazendo condições de contornos apropriadas para as quais a dependência da pressão com a função fluxo poloidal permaneça fixada. É possível calcular a densidade, pressão, temperatura e dimensões do plasma, juntamente com o fluxo magnético como funções do tempo. A teoria á aplicada para o modelo do vórtice de Hill esférico, prolato e oblato, com a condição que a velocidade de difusão não se torne singular no eixo magnético. Os resultados mostram características próprias de contração e expansão da configuração devido a existência de pontos de bifurcação no espaço dos parâmetros / Abstract: We propose the study of the evolution of Field-Reversed Configurations (FRC's) employing Grad-Hogan theory. From the symmetry properties of these configurations it is possible to get general equation for slowly diffusing plasmas. Supposing that the temperature is uniform but time dependent, it can be shown that the evolution is described as a continuous sequence of equilibrium states, satisfying proper boundary conditions for which the dependence of the pressure with the poloidal flux function remains fixed. It is possible to calculate plasma density, pressure, temperature and size, together with magnetic flux as functions of time. The theory is applied to the spherical, prolate and oblate Hill's vortex model, with the condition that the diffusion velocity does not become singular at the magnetic axis. The results show proper characteristics of contraction and expansion of the configuration due the existence of bifurcation¿s points in the parameters space / Mestrado / Física / Mestre em Física