This thesis presents theoretical studies of several x-ray spectroscopies - x-ray absorption, x-ray photoelectron emission, radiative and non-radiative resonant Raman scattering spectroscopy. The main focus point is investigating the influence of nuclear dynamics on these spectra for a variety of small molecules - naphthalene, biphenyl, ethylene, the water dimer, HCl, CO. The theoretical tools used consist of the basic equations of the relevant x-ray spectroscopy. Wave packet methods are also used. The molecular parameters needed for our simulations are obtained through suitable quantum chemical calculations, based on either wave function or density functional methods. Our simulations are compared to experimental data, where available. Simulations of x-ray absorption and x-ray photoionization spectra for naphthalene and biphenyl show that the spectral shapes are heavily influenced by the joint effect of two factors -- chemical shifts and excitations of vibrational progression. Comparison between the two molecules and also comparison to a reference case -- benzene, provides useful insight into the molecular behavior under core excitation. In a further step, we consider the O1s x-ray photoelectron spectrum of the water dimer. A substantial broadening of the two bands originating from the donor and the acceptor oxygen is found. It is caused by excitations of soft intermolecular vibrational modes, associated with the hydrogen bond. Another strong influence of the nuclear dynamics is clearly seen in the resonant x-ray Raman scattering of HCl. Vibrational collapse is observed experimentally and confirmed theoretically for distinctive situations. This effect allows to eliminate completely the vibrational broadening, and hence, considerably increase the spectral resolution. We considered also the vibrational dynamics in resonant soft x-ray Raman scattering from ethylene. The importance of vibronic coupling and symmetry effects is discussed and emphasized. We obtained excellent agreement with the experimental data. We predict an interference effect in the resonant Auger scattering from fixed-in-space molecules. By exciting a molecule to a dissociative state and measuring the angular distribution of the Auger electrons in coincidence with the molecular ion, one can observe this effect. The interference pattern can be used after Fourier transformation for extracting structural data about the studied system. We have found that two-center interference leads to an enhancement of the recoil effect. Finally, it is shown that core excitation to doubly-excited dissociative Pi state is accompanied by Doppler splitting of the atomic peak in resonant Auger scattering from carbon monoxide. / QC 20100910

The gyromagnetic ratio of bound particles is an active field of experimental and theoretical research. Early measurements of corrections to the bound g-factor came from experiments involving hydrogen-like ions. As the sensitivity of such experiments has increased, it has become possible to instead use them to measure the electron-ion mass ratio -- but only if the theoretical bound g-factor is known with sufficient precision for these systems. By constructing an effective nonrelativistic Lagrangian, we derive leading order binding and recoil corrections for systems comprised of particles with arbitrary spin. Lagrangians for spin one-half and spin one-theories are developed, before moving on to the more general case of arbitrary spin. In each case, an effective nonrelativistic Lagrangian taking into account all relevant terms is constructed. The coefficients of this Lagrangian are then fixed by calculating scattering processes in both the relativistic and nonrelativistic theories. A relativistic framework for dealing with particles of arbitrary spin is considered. In this framework the relevant terms in the scattering process are heavily constrained by the symmetries required of the electromagnetic current. This allows the determination of an effective Lagrangian valid for arbitrary spin. It is found that the only coefficients which depend upon the spin of the particle in question involve derivatives of the magnetic field. This general form is consistent with the previously derived Lagrangians for spin one-half and spin one particles. With this effective nonrelativistic Lagrangian, the leading order binding and recoil corrections to the bound gyromagnetic ratio are calculated. These corrections are found to be universal, independent of the spin of the particles involved. This is understood as a consequence of the Bargmann-Michel-Telegdi equation.

The subject of this theoretical  study is the role ofelectronic structure as well as of rotational and vibrational motionson interactions between molecules and electromagnetic radiation,ranging from optical to x-ray. The thesis concerns both linear and nonlinear regimes of the light-matter interaction. The first part of the thesis is devoted to propagation of opticalpulses with different time-structure through various nonlinear absorbers.First we explain the double-exponential decay of fluorescence caused by photobleaching of pyrylium  salt irradiated by a train of short (100 fs) optical pulses. The main reason for this effect is the transversal inhomogeneity of the light beam which makes the dynamics of the photobleaching differ in the core of the pulse and on its periphery. We also explore the optical power limitingof C60 fullerene irradiated by either microsecond optical pulses or a picosecond pulse trains. Enhancement of nonlinear absorption is caused by strong triplet-triplet absorption that becomes important due toelongation of the interaction time.Here we show the importance of the repetitionrate for the optical power limiting performance.The second part of the thesis addresses the interaction of optical and x-rayfields with rotational degrees of freedom of molecules. In this part the main attention is paid to the rotational heating caused by the recoil, experienced by molecules due to the ejection of photoelectrons. We have quantitatively explained two qualitatively different experiments with the N2 molecule.We predict the interference modulation of the recoil-induced shift,which is a shift of the photoelectron line caused by the rotational recoil effect, as a function of the photon energy.The developed theory also explains the rotational heating ofmolecules observed in the optical fluorescence induced by x-ray radiation.Based on this explanation, we suggest a new scheme of the optical fluorescence induced by x-rays that allows to detect the recoil effect via the recoil-inducedsplitting of the optical resonance.The last part of the thesis focuses on multi-mode nuclear dynamics of the resonant Auger scattering from the C2H2 molecule, that was the subject of a recent experimental study.Here we develop a theory that explains the observed vibrationalscattering anisotropy. We have found that three qualitatively different mechanisms are responsible for this phenomenon. The first mechanism is the interference of the direct and resonance scattering channels. The second mechanismis the interference of the resonant scattering channels through core excitedstate with the orthogonal orientation of the vibrational modes of core excitedstate. The Young's double slit like interference of the quantum pathways through the double-well potential of the bending motion of core excited state is the third mechanism of the vibrational scattering anisotropy. / QC 20100713

[pt] O intuito deste trabalho é aplicar metamateriais elásticos na mitigação de esforços impulsivos gerados por um disparo de um armamento. Os impactos ou forças impulsivas são caracterizados por forças de magnitudes muito altas aplicadas em um tempo extremamente pequeno, implicando em grandes acelerações e desacelerações. Tal comportamento é amplamente estudado na literatura nas esferas impactantes do Berço de Newton e este trabalho tem seu início por meio da análise do comportamento dessas esferas e dos modelos das forças de contato entre elas. Em seguida é analisado o Berço de Newton por meio do enfoque da propagação de ondas e uma comparação entre a modelagem numérica e analítica é comprovada. Os metamateriais elásticos, componentes com propriedades especiais, são apresentados e sua característica de bloquear propagações em determinadas faixas de frequência é verificada. Também é desenvolvida experimentalmente uma célula unitária e é feita a comprovação da capacidade de atenuação da propagação de determinada faixa de frequência. O sistema de recuo, local proposto para verificar a eficiência do emprego dos metamateriais, é modelado de forma simplificada, bem como dois novos modelos são propostos com o objetivo de se verificar qual é mais indicado para a aplicação dos metamateriais. Finalmente é feita a modelagem de uma possível aplicação, visando a construção de um dispositivo composto por metamateriais elásticos para ser empregado na mitigação de esforços impulsivos e a redução da força transmitida para o suporte que todo o conjunto está fixo é numericamente comprovada. / [en] The purpose of this work is to apply elastic metamaterials in the mitigation of impulsive efforts generated by a firing of an armament. Impacts or impulsive forces are characterized by very high magnitudes of forces applied in an extremely small period of time, implying large accelerations and decelerations. Such behavior is widely studied in the literature in the impacting spheres of Newton s Cradle and this work has its beginning through the analysis of the behavior of these spheres and its contact force models. Next, Newton s Cradle is analyzed through the wave propagation approach and a comparison between numerical and analytical modeling is proven. Elastic metamaterials, components with special properties, are presented and their feature to block propagation in certain frequency bands is verified. A unit cell is also experimentally developed and its capacity to attenuate the propagation of a particular frequency band is tested. The recoil system, where the efficiency of employing the metamaterials is proposed, is modeled in a simplified way, as well as two new models are proposed in order to verify which one is most suitable for the application of metamaterials. Finally, the modeling of a possible application is made, aiming the construction of a device composed of elastic metamaterials to be employed in the mitigation of impulsive efforts and the reduction of the force transmitted to the support that the whole set is fixed is numerically proven.

Syftet med projektet var att ta fram en rekylsimulator till användning vid torrträning i skidskytte för att tillföra mer realism till träningsformen. Projektet hade som mål att testa ut komponenter till simulatorn, designa ett fäste samt att både genom mätningar och användartester verifiera den framtagna simulatorns validitet. För att med god reliabilitet testa de ingående komponenterna byggdes en testrigg där upprepade tester kunde utföras. Ett fäste togs även fram och itererades på tills en slutgiltig lösning erhölls. De två verifieringsstegen hann ej utföras och de ingående komponenterna uppvisade ej heller egenskaper som är nog väl överensstämmande med uppmätta värden för att garantera goda chanser till en lyckad simulering. I testerna förekom det även problem med den sensor som användes vilket innebar en viss osäkerhet kring erhållna värden. Över lag krävs mer arbete för att finna bättre komponenter, men även för att testa löningsprincipen och dess giltighet / The purpose of the project was to develop a recoil simulator for use in dry training in biathlon to add more realism to the practice. The project aimed to evaluate components of the simulator, design a mounting for the rifle and to verify the validity of the developed simulator through both measurements and user tests. In order to test the constituent components with good reliability, a test rig was constructed where repeated reliable measurements could be performed. A mounting was also designed and iterated upon until a final solution was obtained. The two verification steps were not performed, due to time constraints and the components also did not show properties that were well enough in accordance with measured values to guarantee good chances of a successful simulation. In the tests, there were also problems with the sensor used, which meant there was some uncertainty about the obtained values. In general, more work is required to find better components, but also in order to test the principle and its validity. / <p>2022-07-01</p>

Developing countermeasures dispenser systems requires many and careful tests. When it comes to testing products with pyrotechnics, testing can often be very complicated and expensive. This might lead to no testing at all due to time or resource shortages. Products to be used in the military requires further testing and even more thorough reviews to meet the strict demands placed on the products. In order to enable more tests of pyrotechnic flares in the countermeasures industry, this degree project aims to increase the ability to perform tests without the need for pyrotechnic means. This was done by designing, constructing and optimizing a recoil emulator, an apparatus that imitates the force-time curve obtained by pyrotechnic flares without the need of pyrotechnic means. The construction of the recoil emulator was conducted at a department that develops countermeasure systems at Saab Surveillance in Järfälla. The apparatus aims to be used in the future for testing and verification of product series of countermeasures dispenser systems. The design of the apparatus was based on a test result provided by a flare manufacturer of an arbitrarily chosen flare, typical in the countermeasures industry. Based on the provided test result, three measures were chosen that together describe the fundamental and essential characteristic parts of the recoil motion behavior of pyrotechnic flares. These three measures are in the thesis called \textit{recoil measure} and defined as the Peak Recoil, the Impulse, and the Peak-Width. To be able to verify the recoil emulator, the three recoil measures were implemented in an error model, which was based on the squares of error. In order to make the emulator imitate the desired recoil motion behavior as pleasant as possible, the error model was implemented in an optimization model. By minimizing the error of data points from each of the recoil measures obtained from the real test provided by the manufacturer with results obtained from the recoil emulator, the emulator was verified and optimized accordingly. Results showed that the selected design of the recoil emulator resulted in a force-time curve that principally mimics the curve given by the real tests. The conclusion from the project was, therefore, that it is possible perform tests on countermeasures systems without pyrotechnics when considering the impact of recoil. Further development of this thesis could be to improve the construction of the recoil emulator and perform more research on flares and damping materials. Other future work could be to implement the emulator in existing test and validation processes at companies within the countermeasure industry. / Att utveckla motmedelsprodukter kräver många och noga utförda tester. När det kommer till testning av produkter med pyroteknik kan testerna ofta bli väldigt komplicerade och dyra eller inte göras alls på grund av tid- eller resursbrist. Produkter som ska användas inom militären kräver i många fall ytterligare tester och ännu noggrannare genomgångar för att kunna klara av de tuffa krav som sätts på produkterna. Den här avhandlingen syftade till att möjliggöra fler tester för pyrotekniska medel inom motmedelsindustrin. Detta har gjorts genom konstruktion, design och optimering av en rekylemulator; en apparat som immiterar den kraft-tid kurva som erhålls av pyrotekniska facklor, utan att använda pyrotekniska medel. Konstruktionen och utvecklandet av rekylemulatorn gjordes på uppdrag av en avdelning som utvecklar motmedelssytem på Saab Surveillance i Järfälla. Syftet med emulatorn är att använda den i framtiden vid testning och verifierering av produktserier av motmedelssystem. Designen av apparaten utgick från testresultat som tillhandahållits av en fackeltillverkare av en godtyckligt vald pyroteknisk fackla, vanlig inom motmedelsindustrin. Utifrån testresultaten togs tre mått ut som tillsammans beskriver fundamentala och viktiga karaktäristiska delar av rekylkraftsbeteendet hos pyrotekniska facklor. Dessa tre mått kallas \textit{rekylkraftsmått} och definieras som rekylpeaken, impulsen, samt peakbredden. För att kunna verifiera rekylemulatorn implementerades dessa tre rekylkraftsmått i en felmodell, som baserades på det kvadratiska felet. För att få emulatorn att imitera det önskade rekylkraftsbeteendet så bra som möjligt implementerades en felmodellen i en optimeringsmodell. Genom att minimera felet av datapunkter från varje rekylkraftsmått som erhålls från resultatet av både det verkliga testet, tillhandahållna av tillverkaren, samt med resultat erhållna från rekylemulatoren kunde emulatorns valideras.

<p> A high speed recoil transport system is developed making possible the simultaneous study of many decay products of the compound nucleus 221*Ac. Oeterminati ons of the efficiency properties of the transport system, essential for absolute cross section measurements , are discussed in detail. </p> <p> A study of angular momentum effects is made possibly by synthesis of 221*Ac using three heavy ion reactions. Absolute cross sections for (HI,xn) and (HI,pxn) reaction products are determined relative to established cross sections for production of 150Dy. Relative cross sections for francium production are also determined. </p> <p> A sophisticated statistical model calculation is adapted to provide a framework for interpretation of the results. Some insight is gained into the roles played by basic physical concepts in the systematic of compound nucleus decay in this mass region </p> / Thesis / Doctor of Philosophy (PhD)

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