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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.
481

Collaborative Editing of Graphical Network using Eventual Consistency

Hedkvist, Pierre January 2019 (has links)
This thesis compares different approaches of creating a collaborative editing application using different methods such as OT, CRDT and Locking. After a comparison between these methods an implementation based on CRDT was done. The implementation of a collaborative graphical network was made such that consistency is guaranteed. The implementation uses the 2P2P-Graph which was extended in order to support moving of nodes, and uses the client-server communication model. An evaluation of the implementation was made by creating a time-complexity and a space complexity analysis. The result of the thesis includes a comparison between different methods and by an evaluation of the Extended 2P2P-Graph.
482

Magnetismo orbital em sistemas de muitos elétrons / Orbital magnetism in many electrons systems

Juliana Maria Abreu da Silva Morbec 06 March 2009 (has links)
Neste trabalho investigamos os efeitos do magnetismo orbital sobre o gás de elétrons tridimensional e sobre íons de camadas abertas em matrizes metálicas. Derivamos uma expressão analítica fechada para a energia de troca do gás de elétrons tridimensional na presença de fortes campos magnéticos, incluindo contribuições do segundo nível de Landau e polarização de spin arbitrária. Esse cálculo generaliza e corrige resultados anteriores disponíveis na literatura. Em seguida, realizamos um cálculo numérico da energia de troca do gás de elétrons tridimensional na presença de campos magnéticos, permitindo a ocupação de um número ilimitado de níveis de Landau, possibilitando assim a obtenção da energia de troca para quaisquer valores de campo magnético e densidade. Em uma abordagem independente, usamos as aproximações de Thomas-Fermi e Thomas-Fermi-Dirac para construir modelos simples para a função dielétrica do gás de elétrons tridimensional no regime de campos magnéticos muito fortes (apenas o primeiro nível de Landau ocupado). Finalmente, estabelecemos vínculos entre os tratamentos fenomenológicos e de primeiros princípios do magnetismo orbital em íons de camadas abertas em matrizes metálicas. Esses vínculos forneceram um embasamento teórico para o uso dos termos de polarização orbital em cálculos Kohn-Sham e levaram à obtenção de expressões aproximadas para os funcionais de troca-correlação da teoria do funcional da densidade de corrente. / In this work, we investigate the effects of orbital magnetism in the three-dimensional electron gas and in open-shell ions in a solid. We derive a closed analytical expression for the exchange energy of the three-dimensional electron gas in strong magnetic fields including the contribution of the second Landau level and arbitrary spin polarization. This calculation generalizes and corrects earlier results available in the literature. Next, we perform a numerical calculation of the exchange energy of the three-dimensional electron gas in a magnetic field, allowing several Landau levels to be occupied, to obtain the exchange energy for arbitrary values of magnetic field and density. In an independent approach, we use the Thomas-Fermi and Thomas-Fermi-Dirac approximations to construct simple model dielectric functions for the three-dimensional electron gas in the strong magnetic field regime (where only the lowest Landau level is occupied). Finally, we establish links between the phenomenological and the first-principles treatment of orbital magnetism in open-shell ions in solids. These links provide a theoretical foundation for the use of orbital polarization terms in Kohn-Sham calculations and allow to obtain approximations to the exchange-correlation functionals of current-density functional theory.
483

Probabilidade de detecção de um gap de rapidez na produção do boson de Higgs / Probability of detecting a rapidity gap in the production of the Higgs boson

Thais Scattolini Lorena Lungov 11 September 1995 (has links)
Foi analisada, através de simulação Monte Carlo, a probabilidade de que um gap de rapidez seja observado na produção do boson de Higgs por fusão de bosons vetoriais com massa (W), no LHC (Large Hadron Collider). Foi analisada, também através do uso de Monte Carlo, a possibilidade de que a existência ou não de um gap de rapidez seja usada na distinção de um Higgs produzido por fusão de bosons vetoriais W de outro produzido por fusão de gluons. Os diferentes modelos para tratamento de processos não perturbativos dos códigos Monte Carlo DTUJET e PYTHIA foram comparados. / The gap survival probability for a higgs boson produced by W fusion at the LHC (Large Hadron Collider) is analyzed through Monte Carlo simulation. The possibility of distinguishing between two higgs production mechanisms, W and gluon fusion is studied using Monte Carlo simulation. The two different models for non pertubative processes, used by DTUJET and PYTHIA are compared.
484

Emprego da Microscopia Eletroquímica de Varredura SECM na investigação de processos interfaciais visando o desenvolvimento de sensores químicos / Scanning Electrochemical Microscopy in the investigation of interfacial processes aimed at development of chemical sensors

Macena, Cleidivan Silva 03 February 2017 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-07-07T18:52:22Z No. of bitstreams: 1 CleidivanMacena.pdf: 2189360 bytes, checksum: 599a50d965fad9ff9559783fe4574feb (MD5) / Made available in DSpace on 2017-07-07T18:52:22Z (GMT). No. of bitstreams: 1 CleidivanMacena.pdf: 2189360 bytes, checksum: 599a50d965fad9ff9559783fe4574feb (MD5) Previous issue date: 2017-02-03 / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA) / The present work demonstrated the potential of Scanning Electrochemical Microscopy (SECM) in the understanding of enzymatic systems using the enzymes glucose oxidase (GOx) and the peroxidase of strong root (HRP) as recognition model. In addition, it evaluated different platforms, such as: Graphene (Gr) and Carbon Nanotubes (CNTs) in the response of enzymatic systems through approximation curves and images. In this sense, the reactivity of the GOx and HRP enzymes was evaluated in the generator / collector mode on an insulating platform. In addition, the HRP was studied comparatively on graphene platform Gr, CNTs and on conductive surface. The use of the SECM technique in the investigation of these systems showed its applicability in the investigation of reactions catalyzed by enzymes and also showed that CNTs were the best platform for immobilization of HRP. In addition, it showed the application of SECM in enzymatic systems for the selective determination of compounds isomers: catechol and hydroquinone. / O presente trabalho demostrou a potencialidade da Microscopia Eletroquímica de Varredura (Scanning Electrochemical Microscopy - SECM) no entendimento de sistemas enzimáticos usando as enzimas glicose oxidase (GOx) e a peroxidase de raiz forte (HRP) como modelo de reconhecimento. Ademais, avaliou diferentes plataformas, como: Grafeno (Gr) e Nanotubos de Carbono (CNTs) na resposta de sistemas enzimáticos através de curvas de aproximação e imagens. Neste sentido, a reatividade das enzimas GOx e HRP foi avaliada no modo gerador/coletor sobre plataforma isolante. Adicionalmente, a HRP foi estudada comparativamente sobre plataforma de grafeno Gr, CNTs e sobre superfície condutora. O uso da técnica SECM na investigação desses sistemas mostrou sua aplicabilidade na investigação de reações catalisadas por enzimas e mostrou ainda que os CNTs fora a melhor plataforma para imobilização da HRP. Além disso, mostrou a aplicação da SECM em sistemas enzimáticos para a determinação seletiva de compostos isômeros: catecol e hidroquinona.
485

Regulação financeira internacional uma análise exploratória e impactos sociais da avaliação das agências

Amaral, Amaury de Souza 08 May 2015 (has links)
Made available in DSpace on 2016-04-26T14:55:21Z (GMT). No. of bitstreams: 1 Amaury de Souza Amaral.pdf: 6080140 bytes, checksum: 0cb16a7bf0b53c8f66a4c49527ebc928 (MD5) Previous issue date: 2015-05-08 / The effects of globalization are felt in all countries. Many have socioeconomic scenarios marked by inequality and by indebtedness. In order to liquidate its debts, they capture resources abroad with the issue of the so-called sovereign bonds. The rating agencies are companies that assess risks before the eventual entitling of these titles and issue opinions. Even that they disclose their methodology of evaluation, in fact there is a huge subjective field, which ultimately influence and, often, increasing the domestic interest rate. Although not everyone realizes the size of the social impact of this component, they effectively change the daily reality experienced by citizens. Because of it, we became interested in studying the effects of the impacts caused by risk factors that enter in the economy. For this reason, it was used as a basis a simplified model that simulates an artificial economy, designed to study a network of credit and the effects of fluctuations in interest rates. This model was chosen also for allowing us to capture amplitudes of economic fluctuations in responses to shocks promoted by the insertion of the interest in an evolutionary process. But it was necessary to go beyond. In this study, we propose an extended version of the simplified economic model by inserting a network of consumers with all its amplitude; this is because the previous model was based on the Say law, that starts from the assumptions that all offer generates its own demand. Thus, it does not permit us to investigate the impacts of the interest on the choices made by consumers in their buying process. The Complex System Theory, and all the development that is currently available for computing, among them the modern algorithms with their accuracy and speed, were fundamental to the achievement of the work. We have, also, progressed in the rupture of the traditional economic analyzes characterized by a top-down approach and, through agents models based, we could adopt a bottom-up approach. This was possible with the integration of macro-parameters associated with a micro level of processing. The main conclusion of this work is that the formation of agglomerates (clusters) between businesses, banks and families encourage economic agents. The agents connected by strong ties are benefited to the extent that the asymmetry in the distribution of wealth between firms and households is reduced. On the other hand, the increase in the interest rate leads to a fall in the connections between the agents, causing a dilution of the network and an increase in the asymmetry of the sharing of wealth / cenários socioeconômicos marcados pela desigualdade e pelo endividamento. Para saldarem suas dívidas captam recursos no exterior com a emissão dos chamados títulos soberanos. As agências de rating são empresas que avaliam riscos diante do eventual inadimplemento destes títulos e emitem opiniões. Ainda que divulguem sua metodologia de avaliação, a bem da verdade, existe nela um enorme campo subjetivo, que acaba por influenciar e, não raras vezes, majorar as taxas de juros domésticos. Muito embora nem todos percebam o tamanho do impacto social deste componente, eles efetivamente alteram a realidade vivenciada pelo cidadão em seu dia-a-dia. Assim, interessou-nos estudar os efeitos dos impactos causados pelos fatores de risco que adentram à economia. Para isso, foi utilizado como base um modelo simplificado que simula uma economia artificial, concebido para se estudar uma rede de crédito e os efeitos das flutuações dos juros. Esse modelo foi o escolhido também por permitir capturar as amplitudes das flutuações econômicas em respostas a choques promovidos através da inserção dos juros em um processo evolutivo. Mas foi necessário ir além. Neste trabalho propomos uma versão estendida do modelo econômico simplificado por meio da inserção de uma rede de consumidores com toda a sua amplitude; isto porque o modelo anterior estava baseado na lei de Say, que parte da premissa que toda oferta gera sua demanda. Assim, ele não permite investigar os impactos dos juros sobre as escolhas dos consumidores em seu processo de compra. A teoria dos sistemas complexos e todo o ferramental que atualmente é disponível pela computação, dentre eles os modernos algoritmos com sua precisão e rapidez, foram fundamentais para a consecução do trabalho. Conseguimos, igualmente, avançar na ruptura das análises econômicas tradicionais caracterizadas pela abordagem top down e, por meio de modelos baseados em agentes, pode-se adotar uma abordagem bottom-up. Isto foi possível com as inserções dos macro-parâmetros associados ao processamento a nível micro. A conclusão principal do trabalho é que a formação de aglomerados (clusters) entre empresas, bancos e famílias favorecem os agentes econômicos. Os agentes conectados por laços fortes são beneficiados na medida em que diminui a assimetria na distribuição de riquezas entre firmas e famílias. Por outro lado, o aumento da taxa de juros leva a uma quebra nas conexões entre os agentes, causando a diluição da rede e aumento na assimetria da partilha da riqueza
486

Álgebras de incidência hereditárias por partes / Piecewise hereditary incidence algebras

Silva, Marcelo Moreira da 09 December 2016 (has links)
Apresentamos um estudo das álgebras de incidência que são hereditárias por partes, as quais denominamos Phias, piecewise hereditary incidence algebras. Através da aljava com relações, descrevemos as Phias de tipo Dynkin e introduzimos uma nova família de Phias de tipo Dynkin extendido chamada família ANS, em referência a Assem, Nehring e Skowronski. Nessa descrição, o importante método foi o dos cortes em extensões triviais, os quais inspiraram a elaboração de um programa que concebe exatamente os cortes na extensão trivial dada que resultam em álgebras de incidência. Abordamos as Phias &#922\\&#916 de tipo feixes, estudando o &#922\\&#916-módulo sincero canônico M e a álgebra de extensão por um ponto &#922\\&#916[&#924]. Demonstramos que se &#922Q/I é uma álgebra sincera, quase-inclinada canônica de tipo aljava e tipo de representação infinito, então os &#922Q/I-módulos sinceros são excepcionais. Essa conclusão permite construir uma gama de Phias &#922\\&#916[&#924] de tipo selvagem. Exploramos as Phias simplesmente conexas, provando uma resposta positiva para o problema de Skowronski para &#922\\&#916 uma Phia de tipo H, com grafo de objetos inclinantes &#922_D^b (&#919) conexo: o grupo &#919^1(&#922\\&#916) é trivial se, e somente se, a álgebra &#922\\&#916 é simplesmente conexa. Na área homológica, determinamos um limitante superior da dimensão global forte das Phias; mais ainda, ampliamos esse resultado para as álgebras sinceras provando que dada uma álgebra sincera e hereditária por partes, sua dimensão global forte é menor ou igual a três. / We present a study of incidence algebras that are piecewise hereditary, which we denominate Phias. By means of the quiver with relations, we describe Phias of Dynkin type and introduce a new family of Phias of extended Dynkin type, which we call ANS family, in reference to Assem, Nehring, and Skowronski. In this description, the important method was the one of cuts on trivial extensions, inspiring the writing of a program that shows exactly the cuts on the given trivial extension that result on incidence algebras. We approach sheaves type Phias &#922\\&#916, studying the canonical sincere &#922\\&#916-module M and the one-point extension algebra &#922\\&#916[&#924]. We show that if &#922Q/I is a sincere, quasi-tilted canonical algebra of quiver type and infinite representation type, then sincere &#922Q/I-modules are exceptional. This conclusion allows the construction of a wide range of Phias &#922\\&#916[&#924] wild type. We explore the simply conectedeness of Phias, proving a positive answer of the so called Skowronski problem for &#922\\&#916 a Phia H type, with connected quiver of tilting objects &#922_D^b (&#919): the group &#919^1(&#922\\&#916) is trivial if, and only if, &#922\\&#916 is a simply connected algebra. On homology, we determine an upper bound for the strong global dimension of Phias; furthermore, we extend this result for sincere algebras proving that the strong global dimension of a sincere piecewise hereditary algebra is less or equal to three.
487

STRUCTURAL, TRANSPORT, AND TOPOLOGICAL PROPERTIES INDUCED AT COMPLEX-OXIDE HETERO-INTERFACES

Thompson, Justin K. 01 January 2018 (has links)
Complex-oxides have seen an enormous amount of attention in the realm of Condensed Matter Physics and Materials Science/Engineering over the last several decades. Their ability to host a wide variety of novel physical properties has even caused them to be exploited commercially as dielectric, metallic and magnetic materials. Indeed, since the discovery of high temperature superconductivity in the “Cuprates” in the late 1980’s there has been an explosion of activity involving complex-oxides. Further, as the experimental techniques and equipment for fabricating thin films and heterostructures of these materials has improved over the last several decades, the search for new and more exotic properties has intensified. These properties stem from the interfaces formed by depositing these materials onto one another. Whether it be interfacial strain induced by the mismatch between the crystal structures, modified exchange interactions, or some combination of these and other interactions, thin films and heterostuctures provide an invaluable tool the modern condensed matter community. Simply put, a “complex-oxide” is any compound that contains Oxygen and at least two other elements; or one atom in two different oxidation states. Transition Metal Oxides (TMO’s) are a subset of complex-oxides which are of particular interest because of their strong competition between their charge, spin and orbit degrees of freedom. As we progress down the periodic table from 3d to 4d to 5d transition metals, the crystal field, electron correlation and spin-orbit energies become more and more comparable. Therefore, TMO thin films and heterostructures are indispensable to the search for novel physical properties. KTaO3 (KTO) is a polar 5d TMO which has been investigated for its high-k dielectric properties. It is a band insulator with a cubic perovskite crystal structure which is isomorphic to SrTiO3 (STO). This is important because non-polar STO is famous for forming a highly mobile, 2-Dimensional Electron Gas (2DEG) at the hetero-interface with polar LaAlO3 (LAO) as a result of the so-called “polar catastrophe”. Here, I use this concept of polarity to ask an important question: “What happens at hetero-interfaces where two different polar complex oxides meet?” From this question we propose that a hetero-interface between two polar complex-oxides with opposite polarity (I-V/III-III) should be impossible because of the strong Coulomb repulsion between the adjacent layers. However, we find that despite this proposed conflict we are able to synthesize KTO thin films on (110) oriented GdScO3 (GSO) substrates and the conflict is avoided through atomic reconfiguration at the hetero-interface. SrRuO3 (SRO) is a 4d TMO, and an itinerant ferromagnet that is used extensively as an electrode material in capacitor and transistor geometries and proof-of-concept devices. However, in the thin film limit the ferromagnetic transition temperature, TC, and conductivity drop significantly and even become insulating and lose their ferromagnetic properties. Therefore, we ask “Are the transport properties of SRO thin films inherently inferior to single crystals, or is there a way to maintain and/or enhance the metallic properties in the thin film limit?” We have fabricated SRO thin films of various thickness on GSO substrates (tensile strain) and find that all of our samples have enhanced metallic properties and even match those of single crystals. Finally, we ask “Can these enhanced metallic properties in SRO thin films allow us to observe evidence of a topological phase without the complexity of off-stoichiometry and/or additional hetero-structural layers?” Recent reports of oxygen deficient EuO films as well as hetero-structures and superlattices of SRO mixed with SrIrO3 or La0.7Sr0.3MnO3 have suggested that a magnetic skyrmion phase may exist in these systems. By measuring the Hall resistivity, we are able to observer a topological Hall effect which is likely a result of a magnetic skyrmion. We find that of the THE exists in a narrow temperature range and the proposed magnetic skyrmions range in size from 20-120 nm. Therefore, the SRO/GSO system can provide a more viable means for investigating magnetic skyrmions and their fundamental interactions.
488

Silní a slabí podle Římanům 14-15 / The Strong and the Weak in Romans 14-15

Majtán-Černák, Marek January 2017 (has links)
The present diploma thesis is an exegetical attempt to interpret Paul's parenesis in his Letter to the Romans 14,1-15,13. It tries to find answers to the following questions: Who are the "strong in faith" (15:1)? Who are the "weak in faith" (14:1)? What "day" is meant in chapter 14:5? What kind of dietary restrictions are in the background of 14:2? What is the solution that Paul suggests? The analysis has led to the following conclusions: Paul is trying to resolve a particular dispute between two groups of believers in Rome. The "weak" probably had a problem with the "strong" eating the meat and drinking the wine defiled with idolatry (14:21) and not keeping fasting days, or certain Jewish feast days (14:3). So, the "weak" may be identified as the Jewish Christians and the "strong" with the Christians of gentile origins. Paul tries to move both groups away from judging each other (14:3) to respect the opinion of the other group (14:4) and leads them above all to mutually build loving relationships to each other (14:19). Key words: weak in faith, strong in faith, day, food, dietetary restriction, Lord, Christ, Kingdom of heaven
489

La soutenabilité de l’accumulation du capital et de ses régimes : Une approche macroéconomique en termes de soutenabilité forte / The sustainability of capital accumulation and its regimes : A strong sustainability macroeconomic approach

Cahen-Fourot, Louison 13 October 2017 (has links)
Le sujet de la présente thèse est La soutenabilité de l’accumulation du capital et de ses régimes : une approche macroéconomique en termes de soutenabilité forte. Elle s’articule en deux parties. Deux chapitres composent la première : le chapitre 1 s’inscrit dans le débat sur la possibilité d’un capitalisme stationnaire. Il analyse l’absence des rapports sociaux spécifiques du capitalisme dans les travaux de certains économistes écologiques au moyen d’exemples historiques de crise écologique et des théories éco-marxistes. Le chapitre 2 discute les analyses monétaires de certains économistes écologiques selon lesquelles un état stationnaire est incompatible avec un système dans lequel la monnaie est créée comme une dette portant intérêt en adoptant un point de vue post-keynésien. La deuxième partie est plus empirique et se compose de trois chapitres. Le chapitre 3 examine la relation sociale à l’exergie au sein du régime d’accumulation fordiste et du capitalisme financiarisé et mondialisé. L’approche en termes d’énergie est intégrée à un cadre théorique régulationniste informé par l’approche en termes de démocratie carbone. L’objectif est d’identifier des ruptures dans les modalités d’usage de l’énergie qui accompagnent les transformations observées dans d’autres domaines. Le chapitre 4 prolonge le précédent au moyen d’une analyse économétrique de la relation PIB-CO2 pour la France de 1950 à 2013 en tenant compte de la rupture dans les régularités de l’accumulation du capital entre le régime d’accumulation fordiste et le régime d’accumulation néolibéral ainsi que des possibles asymétries. Le chapitre 5 analyse les ambitions nationales en matière de réduction de gaz à effet de serre, dénommées volontarisme carbone, replacées dans le contexte du capitalisme globalisé et financiarisé contemporain. / The subject of my PhD is The sustainability of capital accumulation and its regimes : a strong sustainability macroeconomic approach. It is composed of two parts. The first one is composed of two chapters that review the literature on two aspects : The first chapter tackles the debate on stationary capitalism. It reviews the way capitalism is taken into account by ecological economists and analyzes it in light of historical examples of ecological crises and of insights from eco-marxist theories. Chapter 2 tackles the debate about the so-called monetary growth imperative analysed from a post-Keynesian point of view. The second part is a more empirical one and is composed of three chapters. Chapter 3 attempts at framing the exergy-useful work approach into a régulationnist theoretical framework informed with insights from the Carbon democracy approach. It investigates the social relationship to energy in the Fordist and Neoliberal accumulation regimes. The fourth chapter attempts at furthering the third chapter by investigating the CO2 - GDP relationship through econometric means taking into account structural breaks between accumulation regimes and possible asymmetries. Chapter 5 investigates the commitment of countries to reduce their greenhousegas emissions within the context of globalized finance-led capitalism.
490

Molecules exposed to Intense, Ultrashort Laser Fields

Förster, Johann Jakob 07 May 2018 (has links)
Das Ionisierungsverhalten kleiner Moleküle (insbesondere H2 und NH3) in intensiven, ultrakurzen Laserfeldern wird theoretisch untersucht. Das Hauptaugenmerk liegt dabei auf dem Einfluss der Kerndynamik. Zunächst wird das Ionisierungsverhalten des H2-Moleküls bei eingefrorener Kernschwingung untersucht. Bereits im Rahmen dieser Näherung kann im Mehrphotonenregime ein zuvor beobachteter Zusammenbruch der Näherung im Gleichgewichtsabstand festgehaltener Kerne erklärt werden. Weiterhin wird der Übergang vom Mehrphotonen zum quasistatischen Ionisierungsregime für 800-nm-Laserfelder untersucht. Eine neuartige Methode zur Beschreibung der korrelierten Schwingungs- und Elektronendynamik des H2-Moleküls (7D) wird entwickelt. Mit dieser Methode wird schließlich der Einfluss der Kernbewegung während des Laserfeldes auf das Ionisierungsverhalten untersucht. Es wird ein sichtbarer Einfluss auf den zuvor diskutierten Zusammenbruch der Näherung festgehaltener Kerne beobachtet. Dies gilt ebenfalls für einen vor kurzem experimentell beobachteten Isotopeneffekt in der Ionisierung der Moleküle H2 vs. D2 untersucht. Im zweiten Teil der Arbeit wird das Ionisierungsverhalten des NH3-Moleküls untersucht. Die Möglichkeit, die Kerngeometrieabhängigkeit zur Erzeugung und Messung von Schwingungswellenpaketen im neutralen NH3-Molekül mittels Lochfraß auszunutzen, wird untersucht. Das erwartete Schwingungsverhalten und die dafür optimalen Laserparameter werden aufgezeigt. Zusätzlich wird die Möglichkeit des Filmens eines tunnelnden Kernwellenpakets im Doppelmuldenpotential entlang der Schwingungskoordinate untersucht. In der Tat sollte die Verwendung extrem kurzer Laserfelder das Drehen eines Echtzeit-Filmes dieses quantenmechanischen Tunnelprozesses ermöglichen. Abschließend werden die Winkelabhängigkeit der Ionisierungswahrscheinlichkeit von NH3 (ähnelt Orbitalgeometrie) sowie elliptisch polarisierte Laserfelder untersucht. / The ionization behavior of small molecules (especially H2 and NH3) exposed to intense, ultrashort laser fields is investigated theoretically. The focus lies on the influence of nuclear dynamics on this ionization behavior. The ionization behavior of the H2 molecule is first examined within the frozen-nuclei approximation. A previously reported pronounced breakdown of the fixed-nuclei approximation can be explained already within this level of approximation. Furthermore, the transition from the multiphoton to the quasistatic ionization regime is studied for 800 nm laser pulses. A novel approach for the correlated description of the electronic-vibrational motion of the H2 molecule (7D) is developed. The influence of vibrational dynamics during the laser field on the ionization behavior is investigated using this method. A pronounced difference on the previously discussed breakdown of the fixed-nuclei approximation is observed. The vibrational dynamics also lead to a notable change for a recently experimentally observed isotope effect in the ionization of the molecular isotopes H2 vs. D2. The ionization behavior of the NH3 molecule is studied in the second part of this thesis. The possibility to exploit the geometry dependence of the ionization yield in order to create and measure vibrational wave packets in the neutral NH3 molecule via Lochfraß is explored. The expected vibrational dynamics and the optimal laser parameters to observe this effect are demonstrated. Furthermore, the possibility to shoot a "movie" of a tunneling wave packet in the double-well potential along the vibrational coordinate is investigated. Indeed, extremely short laser fields should allow creating a real-time movie of the quantum-mechanical tunneling process. Finally, the orientation dependence of the ionization yield of the NH3 molecule (reflecting the orbital shape) and elliptically polarized laser fields are studied.

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