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1
Li, Bo. "Inelastic collision and three-body recombination." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29779.
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Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009.Committee Chair: M. Raymond Flannery; Committee Member: Daniel Goldman; Committee Member: Dewey H. Hodges; Committee Member: Li You; Committee Member: Turgay Uzer. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Zhu, Ling. "Dynamic inelastic behaviour of ship plates in collision." Thesis, University of Glasgow, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324960.
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McCrudden, Garreth. "Vector correlations in gas-phase inelastic collision dynamics." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:967fbe54-98a9-48e9-a0b2-707811804d7a.
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This thesis presents a joint experimental and theoretical study of vector correlations in the electronically, vibrationally, and rotationally inelastic collisions of simple molecules with rare-gas atoms. In the first instance, empirical and calculated data are presented for rotationally inelastic scattering in the NO(X)+Ar and ND3(X̃)+Ar systems at collision energies in the range 405-2210 cm-1. These experiments - the first to be conducted on a newly commissioned crossed-molecular beam machine - measured the k-k' correlation, i.e. that between the vectors describing the relative velocities before and after collision, respectively. The empirical data were subjected to rigorous comparison with both quantum-mechanical and quasi-classical trajectory (QCT) calculations. For both the NO(X)+Ar and ND3(X̃)+Ar systems, there is generally good agreement between experiment and theory at all four collision energies investigated. Two chapters of this thesis focus on the development of trajectory surface-hopping (TSH) QCT models of the OH(A, v = 0)+Kr and OH(A, v = 0)+Xe systems. Experimental data relating to scalar quantities (rotational energy transfer (RET) and electronic quenching) and to the j-j' correlation (which quantifies the depolarisation of the angular momentum of the OH(A) radical) are compared to variable-collision-energy TSH QCT calculations in which the length of the OH bond is fixed. The algorithms involve all three PESs of the OH(A/X)+Kr system, and the full range of electrostatic and roto-electronic mechanisms that couple them, for the first time. The most complete model succeeded in accounting for 93% of experimentally observed quenching. For the OH(A/X)+Xe system, coupling matrix elements were estimated from those of OH(A/X)+Kr, and the most complete model recovered 63% of experimentally observed quenching. This thesis also presents a novel theoretical study of rotationally inelastic dynamics in the OH(A, v = 1)+Kr system. Provisional results from adiabatic calculations in which the OH bond length is allowed to vary over the course of a trajectory are presented alongside experimental data that were reported previously. To date, these calculations continue to underestimate the extent of empirical RET data. Reasons for the observed discrepancy, and suggestions to resolve it, are outlined in detail.
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Clare, Suzanne. "A quasiclassical analysis of inelastic energy transfer in molecular collision systems." Thesis, University of Sussex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298671.
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Manolopoulos, David Eusthatios. "Close-coupled equations : the log derivative approach to inelastic scattering, bound state and photofragmentation problems." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254402.
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Akbiyik, Melike [Verfasser], and T. [Akademischer Betreuer] Müller. "Inelastic diffractive event classification in proton-proton collision with the CMS experiment / Melike Akbiyik ; Betreuer: T. Müller." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1164081012/34.
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Konishi, Hideki. "Collisional stability of localized metastable ytterbium atoms immersed in a Fermi sea of lithium." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225386.
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Jurčík, Michal. "Modelování elastických a neelastických kolizí." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220296.
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Master's thesis deals with vehicles collisions within an environment of logistic distribution storehous. The aim is to avoid potential collisions that can occur between these vehicles. In the first chapter are detailed collisions of particles and elements impact for the law of conservation of energy and momentum. In further sections is carried out detailed research of elastic and inelastic collisions in an ideal environment, which are the theoretical basis for the simulation of the real environment. Collisions are supported by detailed calculations and added pictures. The second chapter deals with the development of double-layer application simulating elastic collisions in an ideal environment. In subchapters are descriptions of the classes and methods for computing prediction of collisions with examples of source code. The last section describes the software platform JavaFX and used animation classes that are required for visualization issues. The last chapter, which is the main goal of the work is done by the expansion of the existing design environment of storehouse and vehicles. Particular chapters then describe the cases of various types of collisions their detection and avoidance. There is an application designed to address this issue, with a description of the classes and methods. Used methods are supported with flowcharts for easier understanding.
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Gannouni, Mohamed Achref. "Approche théorique des collisions réactives de type ion-molécule." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1108/document.
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La collision entre l'ion hydroxyle (OH+) et l'atome d'hydrogène (H) joue un rôle majeur en physico-chimie de l'atmosphère et en astrophysique. Pour l'étude de ce système, nous avons générés la surface d'énergie potentielle tridimensionnelle (SEP-3D) globale doublet de la réaction H + OH+ --- H2O+ (X2B1)--- O + H2+. Les calculs électroniques ont été effectués au niveau MRCI avec la base aug-cc-pV5Z en incluant la correction des erreurs de superposition de base (BSSE). Cette SEP couvre la région moléculaire et les régions des longues portées pour les différents canaux : OH+ + H, O + H2+ et la réaction d'échange d'hydrogène. La qualité de la SEP a été validée après une comparaison des constantes spectroscopiques de H2O+ (X2B1) et des fragments diatomiques, des niveaux rovibroniques de H2O+ (X2B1), l'énergie de dissociation et de la barrière à linéarité pour H2O+ (X2B1) aux données expérimentales et théoriques existantes. Un bon accord est trouvé. Après avoir déterminé la SEP, nous avons utilisé les outils de la dynamique quantique indépendante du temps pour calculer les sections efficaces élastiques et inélastiques désexcitation de OH+ (v=0, j=1, 2, 3, 4, 5, 6 et 7) en collision avec l'atome d'hydrogène sur un large domaine d'énergie cinétique. Nous avons ainsi déterminé les taux désexcitation rotationnelle pour des températures allant de 10 à 200K. Nous avons également utilisé la surface quadruplet de Martinez et al. pour déduire ces taux désexcitation. Les résultats montrent que les sections efficaces inélastiques calculées sur la surface doublet sont en moyenne au moins deux à trois fois plus importantes que leurs correspondantes obtenues sur la surface quartet. Les potentiels à longue portée des deux surfaces étant identiques, ce résultat montre qu'un modèle basé sur la seule longue portée du potentiel ne pourrait pas rendre compte de la dynamique inélastique de ce systèmeThe collision between the hydroxyl cation (OH+) and hydrogen atoms (H) plays a major role in physical chemistry of the atmosphere and astrophysics. To study this system, we generated the global three-dimensional potential energy surface (3D-PES) of the reaction H + OH+ ---- H2O+ (X2B1) ---- O + H2+. The electronic calculations were performed at the MRCI level with aug-cc-pV5Z basis including the basis set superposition error (BSSE) correction. This PES covers the molecular region and the long ranges close to the OH+ + H, O + H2+ and the hydrogen exchange channels. The quality of the PES is checked after comparison of the spectroscopic constants of H2O+ (X2B1) and of the diatomic fragments, the rovibronic levels, the dissociation energy, and the barrier to linearity of H2O+ (X2B1) to available experimental and theoretical data. A good agreement is found. Then, we used the tools of time-independent Quantum Dynamics to calculate the elastic and inelastic cross sections for the de-excitation of OH+ in collision with the hydrogen atom over a wide range of kinetic energy. We have thus determined the rotational de-excitation rate coefficients for temperatures ranging from 10 up to 200K. The results show that the inelastic cross sections on the doublet surface are on average at least two to three times larger than their cross section obtained on the previously computed cross sections using the quartet surface. Since, the long range parts of the doublet and the quartet PESs are identical, our work invalidates hence previous cross section determination. When only long range potentials are considered. Therefore, we recommend using fully the global 3D PES for scattering and reactive collision relevant for atmospheric and astrophysical studies
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Gilmore, Jason R. "Search for contact interactions in deep inelastic scattering." Connect to this title online, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu983824358.
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Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xx, 143 p.; also contains graphics. Includes abstract and vita. Advisor: L. Stanley Durkin, Dept. of Physics. Includes bibliographical references (p. 137-143).
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Perkins, Thomas Edward James. "The effects of electronic quenching on the collision dynamics of OH(A) with Kr and Xe." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:5998e249-35ff-4d05-9c13-9b65d59b11d9.
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This thesis presents an experimental and theoretical study of the collision dynamics of OH(A2Σ+) with Kr and Xe. These two systems both exhibit a significant degree of electronically non-adiabatic behaviour, and a particular emphasis of the work presented here is to characterise the competition and interplay between electronic quenching on the one hand, and electronically adiabatic collisional processes on the other. Quenching takes place close to the bottom of the deepest potential well for both systems. In collisions that remain in the excited electronic state, this same region of the potential is also largely responsible for rotational energy transfer (RET) and the collisional depolarisation of angular momentum. Therefore, the direct competition between these processes suppresses the cross-sections for RET and collisional depolarisation from their expected value in the absence of quenching. To investigate this, experiments were carried out to measure cross-sections for the collisional transfer of electronic, vibrational and rotational energy in OH(A, v=0,1) + Kr and OH(A, v=0) + Xe. In addition, measurements were made of the j-j' correlation -- that is, the relationship between the angular momentum of the OH radical before and after a collision -- in collisions with Kr and Xe, using the experimental technique of Zeeman quantum beat spectroscopy. Collisions with both Kr and Xe tend to effectively depolarise the angular momentum of the OH radical, due to the very anisotropic character of the potential on which the process occurs. Electronic quenching, which plays an essential role in both systems, is more prevalent with xenon as the crossing to the ground state potential is located in a more accessible location. These experimental results were compared with single surface quasi-classical trajectory (QCT) calculations, where the overestimate of rotational energy transfer or collisional depolarisation helps to elucidate the degree to which the presence of quenching suppresses these processes. Surface hopping QCT was then used to account for non-adiabatic transitions in the theory, which led to an improvement in agreement with experiment. However, standard surface hopping QCT theory failed to account for the full extent of quenching in these two systems. A major focus of this work is therefore on the development of an extension to standard surface hopping QCT theory to incorporate rovibronic couplings. In non-linear configurations, the excited state of the OH + Kr, Xe systems has A' symmetry, while the ground state is split into symmetric (A') and antisymmetric (A'') components. For these symmetry reasons, coupling is restricted to the two states of the same symmetry, however a rotation of the correct (A'') symmetry can induce transitions to the A'' state too. Inclusion of all three electronic states, and the relevant couplings between them, is found to be crucial for a proper description of experimental reality.
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Newell, Catherine A. "INELASTIC COLLISIONS IN COLD DIPOLAR GASES." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/30.
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Inelastic collisions between dipolar molecules, assumed to be trapped in a static electric field at cold (> 10−3K) temperatures, are investigated and compared with elastic collisions. For molecules with a Λ-doublet energy-level structure, a dipole moment arises because of the existence of two nearly degenerate states of opposite parity, and the collision of two such dipoles can be solved entirely analytically in the energy range of interest. Cross sections and rate constants are found to satisfy simple, universal formulas. In contrast, for molecules in a Σ electronic ground state, the static electric field induces a dipole moment in one of three rotational sublevels. Collisions between two rotor dipoles are calculated numerically; the results scale simply with molecule mass, rotational constant, dipole moment, and field strength.
It might be expected that any particles interacting only under the influence of the dipole-dipole interaction would show similar behavior; however, the most important and general result of this research is that at cold temperatures inelastic rate constants and cross sections for dipoles depend strongly upon the internal structure of the molecules. The most prominent difference between the Λ-doublet and rotor molecules is variation of the inelastic cross section with applied field strength. For Λ-doublet dipoles, cross sections decrease with increasing field strength. For rotor dipoles, cross sections increase proportionally with the square of field strength. Furthermore, the rate constants of the two types of molecules depend very differently on the angular orientations of the dipoles in the electric field.
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Hérault, Joël. "Etude experimentale du ralentissement d'ions lourds de 20 a 100 mev par nucleon dans la matiere." Toulouse 3, 1988. http://www.theses.fr/1988TOU30075.
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Etude experimentale a l'aide d'ions lourds de l'accelerateur ganil sur le spectrometre lise (analyse en energie et en angle) pour determiner le pouvoir d'arret de 11 cibles gazeuses avec une incertitude de plus ou moins 3%. Mise en evidence d'une disparition de la difference entre pouvoirs d'arret des materiaux solides et gazeux lorsque la charge de l'ion tend vers son numero atomique. Analyse des distributions en energies pour de nombreux ions (de l'oxygene au molybdene) et analyse de la distribution angulaire dans des cibles solides et gazeuses. Comparaison des donnees experimentales aux calculs quantiques et classiques
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Sirmas, Nick. "Shock Instability in Gases Characterized by Inelastic Collisions." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23799.
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The current study addresses the stability of shock waves propagating through dissipative media, analogous to both granular media and molecular gases undergoing endothermic reactions.
In order to investigate the stability, a simple molecular dynamics model was developed to observe shock waves and their structures with the inclusion of energy dissipation. For this, an Event Driven Molecular Dynamics model was implemented in a 2D environment, where a molecule is represented by a disk. The simulations addressed the formation of a shock wave in a gas by the sudden acceleration of a piston. Inelastic collisions were assumed to occur only if an impact velocity threshold is surpassed, representing the activation energy of the dissipative reactions.
Parametric studies were conducted for this molecular model, by varying the strength of the shock wave, the activation threshold and the degree of inelasticity in the collisions. The resulting simulations showed that a shock structure does indeed become unstable with the presence of dissipative collisions. This instability manifests itself in the form of distinctive high density non-uniformities behind the shock wave, which take the form of convective rolls. The spacing and size of this ``finger-like" unstable pattern was shown to be dependent on the degree of inelasticity, the activation energy, and the strength of the driving piston.
The mechanism responsible for the instability was addressed by studying the time evolution of the material undergoing the shock wave compression and further relaxation. It is found that the gas develops the instability on the same time scales as the clustering instability in homogeneous gases, first observed by Goldhirsch and Zanetti in granular gases. This confirmed that the clustering instability is the dominant mechanism.
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Marinakis, Sarantos. "The dynamics of inelastic and reactive bimolecular collisions." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424735.
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Nichols, Bethan. "Inelastic collisions of hexapole state selected NO(X)." Thesis, University of Oxford, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.714069.
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Signal, Anthony Ian. "Deep inelastic scattering and bag model." Title page, abstract and contents only, 1988. http://web4.library.adelaide.edu.au/theses/09PH/09phs578.pdf.
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Krohn, Sven. "Inelastic collisions and recombination between electrons and molecular ions." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963450018.
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Wilson, Emma. "Gamma spectroscopy of 207Tl126 populated in deep-inelastic collisions." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/807041/.
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Marshall, David Paul. "The role of correlation in inelastic ion-atom collisions." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238989.
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Richardson, J. P. "Rotationally inelastic collisions in Li2*-rare gas scattering experiments." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240593.
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Valiente-Dobon, Jose Javier. "Studies of neutron-rich nuclei using deep inelastic collisions." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/843390/.
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A deep inelastic reaction between a thin self-supporting 19878Pt target and an 850MeV 13654Xe beam has been used to populate and study both neutron-rich nuclei around the beam and target masses and the reaction mechanism. An Ipi= 10+ isomeric state has been found in the N = 80 isotone 13656Ba with a measured half-life of 91 +/- 2ns. The structure of the predominantly (h11/2)-210+ isomer is discussed in terms of shell model and pair-truncated shell model calculations and compared to the even-Z, N = 80 isotones ranging from 13050Sn to 14868Er. A qualitative explanation of the observed dramatic decrease in the B(E2 : 10+ → 8+) value for the N = 80 isotones at 136Ba is given in terms of the increasing single-particle energy of the h11/2 neutron configuration as the proton sub-shell is filled. A 4-quasiparticle isomer has been observed in with a half-life of 188 +/- 38ns. The results are compared with blocked BCS Nilsson calculations which favour the Kpi= 15- interpretation. This isomer completes the even-A tungsten, 4-quasiparticle isomer systematics from A = 176 to 186. A high spin isomeric state has been found in the near spherical nucleus 19874W with a half-life of 36 +/- 2ns. The nature of this isomer has been interpreted from an examination of the systematics of platinum isotopes and neighbouring nuclei as a tentative Ipi= 12+ state from rotation-aligned, two neutron (i13/2)2configuration. Using prompt-delayed gamma-ray correlations, the complementary fragments of the reaction have been studied and used to identify new states in 19476Os. The angular momentum transfer to the binary fragments in the reaction has been investigated in terms of the average total gamma-ray fold versus the scattering angle of the recoils.
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Xiang, Yang. "Interaction d’atomes /ions hydrogène rapides (keV) avec des surfaces : diffraction et formation d’ions négatifs." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112161/document.
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Le travail de cette thèse porte sur l’étude expérimentale de la diffusion d’atomes d’hydrogène sur des surfaces et sous incidence rasante. L’énergie des atomes et des ions varie de quelques centaines d’eV à quelques keV, tandis que les surfaces étudiées sont des isolants et des semi-métaux. En particulier on a étudié la formation de l’ion H- sur du graphite pyrolytique dit HOPG (highly oriented pyrolytic graphite) et sur une surface de LiF(001). Pour ce dernier système, nous avons étudié en détail la diffraction d’atomes H° et d’ions H+. Ces expériences ont été réalisées sur un montage expérimental utilisant un faisceau pulsé et permettant de détecter en coïncidence les particules diffusées et les électrons secondaires. L’ensemble permet de connaître la charge finale de la particule diffusée, sa perte d’énergie, son angle de diffusion, le tout en corrélation avec la statistique et l’énergie des électrons émis.Le résultat de ce travail a révélé que la diffraction persiste dans le régime inélastique. En effet, nous observons un motif de diffraction après la neutralisation de proton sur la surface de LiF(001). Un modèle est proposé pour expliquer ces résultats qui semblent en contradiction avec ceux publiés par le groupe de H. Winter sur la diffraction d’atomes d’hydrogène sur cette même surface. Concernant la formation d’ion négatif sur HOPG, nous avons mis en évidence un taux de H- (~10%) sur une surface propre. C’est le plus haut taux de H- jamais observé avec ce type d’expérience en incidence rasante. C’est encore plus élevé qu’avec des isolants ioniques, ces derniers donnant un taux déjà 10 fois plus grand que celui observé sur métaux propres. Ces résultats confirment l’efficacité du graphite à convertir des ions et des atomes en ions négatifs. En exploitant les données fournies par la technique des coïncidences, nous avons pu élucider le mécanisme à l’œuvre dans cette conversion. Du fait de la structure électronique particulière de HOPG, avec une bande interdite projetée dans la direction Gamma, seuls les électrons localisés sigma contribuent à la formation de l’ion négatif, donnant au HOPG un caractère isolant du point de vue de la capture électronique. Les électrons pi contribuant de manière efficace à la perte d’énergie par collisions binaires, donnant de ce point de vue au HOPG son caractère métalliqueIn this thesis, we have investigated experimentally the scattering of hydrogen atoms and ions on solid surfaces at grazing incidence. The projectile energy ranges from several hundred eV to few keV. The formation of H- ions is studied on highly oriented pyrolytic graphite (HOPG) surface; and surface diffraction is carried out on LiF(001) surface with H° and H+ particle scattering. Both experiments were performed in the same experimental setup (see Figure 1.2 and 2.1)—with grazing scattering geometry and a PSD (position sensitive detector) located downstream to record scattered particles. For charge state analysis a set of electrostatic plates is inserted between sample and PSD. During the experiment, coincident measurement technique is used to identify the energy loss associated to 0, 1, 2…electrons emission. Clear evidence of diffraction with inelastic scattering by proton on LiF(001) has been obtained, which has not been observed before. Indeed, the group of H. Winter reported that no diffraction exists with inelastic scattering of H° on LiF(001). However, according to our result, a coherence scattering factor still exists even though the electron capture by the proton is an inelastic process. For negative ion formation on HOPG surface, we report here the highest fraction of H- (~10%) measured in grazing scattering experiments; it is larger than those obtained on ionic insulators, the latter being typically 10 times larger than those measured on clean metals. These results confirm the high yields of negative hydrogen ions from graphite reported in the literature. Electron emission and energy loss of scattered beam have also been deciphered via coincidence measurement. Due to the special structure of HOPG, two kinds of electron emissions (σ and π-band electron) and energy losses (cycles and metal-like energy loss) have been measured. Furthermore, the total electron emission on HOPG with insulator-like behavior and total energy loss with metal-like are the most representative property of HOPG which have been first presented in this thesis
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Yip, Timothy C. Y. "Inelastic J/ψ photoproduction in electron-proton collisions at HERA." Thesis, University of Oxford, 1996. http://ora.ox.ac.uk/objects/uuid:fa45c1a1-3412-4c67-b82f-1595f90dd5c9.
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The development of a neural network based electron finder designed for the ZEUS calorimeter is described. A study of elastic and inelastic J/ψ meson production in electron-proton collisions at HERA using the ZEUS detector is presented. During the 1993 and 1994 running periods, the ZEUS detector collected ~ 500 nb-1 and ~ 3 pb-1 of data respectively. The direct inelastic J/ψ photoproduction cross-section is measured for both running periods and an attempt is made to extract the gluon density inside the proton using the 1994 inelastic J/ψ sample.
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BERGNES, BRASEY CHANTAL. "Etude des processus directs elastique et inelastiques se produisant lors de la collision entre un ion d'helium et une cible d'hydrogene, pour une energie variant de 1,5 a 30 kev." Toulouse 3, 1988. http://www.theses.fr/1988TOU30204.
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Etude des sections efficaces doublement differentielles des processus elastiques et inelastiques au cours de la collision d'un faisceau d'ions de he avec h ou h::(2), entre 1,5 et 30 kev, pour des angles de diffusion compris entre 5' et 30**(o), par spectrometrie de perte d'energie du projectile. Comparaison des resultats a des valeurs calculees et mesurees anterieurement a d'autres auteurs. Proposition d'un modele permettant d'interpreter les resultats pour la cible h
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Baumgartner, Sean. "COLLISIONAL DEPOLARIZATION OF THE ATOMIC SODIUM 3S2S1/2 → 3P2P3/2 → 5S2S1/2 TRANSITION WITH ARGON AND XENON BUFFER GAS BY SPECTRAL HOLE-BURNING." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1311956327.
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Schilling, Frank-Peter. "Diffractive jet production in deep inelastic e+p collisions at HERA." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961853298.
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Collins, Timothy L. D. "Inelastic rotational transfer differential cross-sections for Li2-rare gas collisions." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282082.
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Randall, Colin James. "State-resolved dynamics of electronically inelastic collisions of small free radicals." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/12833.
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The phenomenon of collision-induced electronic energy transfer in selectively excited diatomic radicals has been investigated experimentally. Direct laser excitation of initial rovibronic states and dispersed, temporally-resolved fluorescence analysis of both parent and collisionally populated levels has allowed the collisional encounter to be quantified at a state-specific level. Theoretical modelling of these results allows the form of the potential energy surfaces which control the dynamics to be established. In an extended series of experiments, collision-induced C2Δ-B2Σ+ transfer in the SiF radical has been investigated. It was observed that the product B2Σ+ state vibrational distributions were well correlated with the Frank-Condon overlap between vibronic wavefunctions of the two states. Dominant channels were found to involve Δv=0, which corresponds to the energy defect of ~5000 cm-1. Rotationally resolved investigation of the C2Δ, v=0→B2Σ+, v'=0 channel revealed a significant fraction of this energy to be released as product state rotation. A limiting impulsive model of the energy release reproduced the main features of the observed behaviour. Polarisation resolved investigation of the transfer event revealed significant depolarisation of the product B2Σ+ state compared to the initial C2Δ state. This observation was rationalised within two dynamically distinct models of rotational energy transfer. It is believed that all these observations may be explained by the valence-Rydberg nature of the electronic states involved. In a related set of experiments, novel measurements of collision-induced transfer between the A2Δ and B2Σ- states of the CH radical have been obtained.
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Kant, David. "A study of the fragmentation of quarks in e-p collisions at HERA." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338959.
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Dunne, Gerald V. "Deep inelastic scattering and the EMC effect /." Title page, contents and introduction only, 1986. http://web4.library.adelaide.edu.au/theses/09SM/09smd923.pdf.
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Bass, Steven David. "Spin dependent effects in quantum chromodynamics /." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phb317.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1993.Copies of three of the author's previously published articles inserted as appendix B. Includes bibliographical references.
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Lemeshko, Mikhail [Verfasser], and Bretislav [Akademischer Betreuer] Friedrich. "Vector correlations in rotationally inelastic molecular collisions / Mikhail Lemeshko. Betreuer: Bretislav Friedrich." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2011. http://d-nb.info/101475660X/34.
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Connolly, Colin Bryant. "Inelastic Collisions of Atomic Antimony, Aluminum, Erbium and Thulium below 1 K." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10517.
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Inelastic collision processes driven by anistropic interactions are investigated below 1 K. Three distinct experiments are presented. First, for the atomic species antimony (Sb), rapid relaxation is observed in collisions with \(^4He\). We identify the relatively large spin-orbit coupling as the primary mechanism which distorts the electrostatic potential to introduce significant anisotropy to the ground \(^4S_{3/2}\) state. The collisions are too rapid for the experiment to fix a specific value, but an upper bound is determined, with the elastic-to-inelastic collision ratio \(\gamma \leq 9.1 x 10^2\). In the second experiment, inelastic \(\mathcal{m}_J\)-changing and \(J\)-changing transition rates of aluminum (Al) are measured for collisions with \(^3He\). The experiment employs a clean method using a single pump/probe laser to measure the steady-state magnetic sublevel population resulting from the competition of optical pumping and inelastic collisions. The collision ratio \(\gamma\) is measured for both \(\mathcal{m}_J\)- and \(J\)-changing processes as a function of magnetic field and found to be in agreement with the theoretically calculated dependence, giving support to the theory of suppressed Zeeman relaxation in spherical \(^2P_{1/2}\) states [1]. In the third experiment, very rapid atom-atom relaxation is observed for the trapped lanthanide rare-earth atoms erbium (Er) and thulium (Tm). Both are nominally nonspherical \((L \neq 0)\) atoms that were previously observed to have strongly suppressed electronic interaction anisotropy in collisions with helium \((\gamma > 10^4-10^5, [2,3])\). No suppression is observed in collisions between these atoms \((\gamma \lesssim 10)\), which likely implies that evaporative cooling them in a magnetic trap will be impossible. Taken together, these studies reveal more of the role of electrostatic anisotropy in cold atomic collisions.Physics
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Lee, Teck Ghee. "Theoretical investigations of inelastic processes in slow to fast ion-atom collisions /." Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.
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Magill, Peter David. "Classical resonance in vibrationally inelastic collisions of diatomic molecules : experiments and modeling." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14727.
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Hornung, Balázs. "Rotational polarisation effects in the inelastic collisions of NO(X) and Ar." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:3fe4368b-6e16-469b-89bf-c8847203234e.
Full textAbstract:
Rotational polarisation effects have been investigated in the rotationally inelastic collisions of NO(X) and Ar by means of theoretical and experimental methods. Rotational polarisation describes the correlation between the k–k'–j' vectors, that is the initial and final relative velocities of the colliding partners and the final rotational angular momentum of the diatom, respectively. The simplest types of polarisation are the rotational orientation, or preferred sense of rotation, and the rotational alignment, or preferred plane of rotation. They are quantised by the renormalised polarisation dependent differential cross sections (PDDCSs) In this thesis the theoretical methods included exact quantum mechanical, quasi- classical trajectory and Monte Carlo classical hard shell calculations. Various features of the interaction potential influence differently the polarisation dynamics. The effects of attraction and soft repulsion were elucidated employing a number of differently modified potentials. The rotational alignment is primarily determined by a classical impulsive, or hard shell mechanism at a collision energy of 66 meV. The attractive and soft repulsive forces only perturb this underlying mechanism. On the other hand, the parity dependent oscillations of the open shell alignment moments are due to differences between the quantum mechanical differential cross sections. It has been shown the bigger the well depth compared to the collision energy, the less applicable becomes the classical hard shell model to describe rotational alignment. The quantum mechanical rotational alignment in the collisions of hard shells was also calculated. The classical and quantum mechanical hard shell models predict different rotational alignment. Nevertheless, the classical alignment is a good approximation to the exact quantum mechanical results. The rotational orientation is much more sensitive to the details of the interaction potential. It does not exist in the classical description of hard shell collisions, if the system exhibits certain symmetry properties. The attraction and finite range repulsion break this symmetry and leads to the molecule having a preferred sense of rotation. In general there is non-vanishing rotational orientation in the collisions of a hard shell in the framework of quantum mechanics. This is due to the finite spatial and temporal interaction of the colliding partners. Quantum mechanical interference effects also play an important role in this phenomenon. The rotational alignment was experimentally determined in the collisions of NO(X) and Ar at collision energy of 66meV with a hexapole state selective ion-imaging apparatus. An algorithm was developed based on the Fourier moment analysis to extract rotational polarisation information from the experimental ion images. It is fast and robust and can also be of used to simulate experimental images. This algorithm was used to retrieve the experimental renormalised PDDCSs ion images. The measurements confirmed that a classical, impulsive dynamics is mainly responsible for the rotational alignment in these collisions.
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Martinez, Osorio Yeisson Fabian. "Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra." Doctoral thesis, Uppsala universitet, Teoretisk astrofysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-249168.
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Chemical abundances as measured from stellar spectral lines are often subject to uncertainties due to lack of accurate data for inelastic collisions, which is needed for non-local thermodynamic equilibrium (non-LTE) modelling. For cool stars, understanding of collision processes with electrons and hydrogen atoms is required to achieve high precision measurements. In this thesis, I have investigated the role of these collisions on the non-LTE formation of Li and Mg spectral lines in late-type stars. In the case of Li, electron impact excitation processes were calculated using the R-matrix with pseudo states method and the results found to agree well with recent calculations using the convergent close-coupling technique. These modern data were employed in non-LTE calculations by updating an existing model atom, which already included modern data for hydrogen collision processes. Our results were compared with calculations using older semi-empirical approximation calculations and only small differences were found: about 0.01 dex (~ 2%) or less in the abundance corrections. We therefore conclude that the influence of uncertainties in the electron collision data on non-LTE calculations is negligible. Indeed, together with the collision data for the charge transfer process Li + H ↔ Li+ + H- now available, and barring the existence of an unknown important collisional process, the collisional data in general is not a source of significant uncertainty in non-LTE Li line formation calculations. In the case of Mg, electron impact excitation processes were again calculated with the Rmatrix with pseudo states method, and used together with recent hydrogen collision calculations to build and test a model atom, without free parameters, for non-LTE modelling. Both electron and hydrogen collision processes, including charge transfer and excitation, are found to be important thermalising agents in various cases. The modelled spectra agree well with observed spectra from benchmark stars in the optical and infrared. The modelling predicts non-LTE abundance corrections ∆A(Mg)NLTE–LTE in dwarfs, both solar metallicity and metal-poor, to be very small (of order 0.01 dex), even smaller than found in previous studies. In giants, corrections vary greatly between lines, but can be as large as 0.4 dex. Results of calculations in a large grid of 1D model atmospheres are presented, and the implications for studies of Mg discussed. The propagation of uncertainties in the inelastic collision data to those in stellar abundances is investigated, and found to lead to small uncertainties, once again typically less than 0.01 dex (2%), although for few stellar models in specific lines (e.g., metal-poor suns, in the 7691 Å line) uncertainties can be as large as 0.03 dex (7%).
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Au, Yat Shan. "Inelastic collisions of atomic thorium and molecular thorium monoxide with cold helium-3." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11318.
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We measure inelastic cross sections for atomic thorium (Th) and molecular thorium monoxide (ThO) in collisions with $^3$He at temperatures near 1 K. We determine the Zeeman relaxation cross section for Th ($^3$F$_2$) to be $\sim 2 \times 10^{-17}$~cm$^{-2}$ at 800~mK. We study electronic inelastic processes in Th ($^3$P$_0$) and find no quenching even after $10^6$ collisions at 800~mK. We measure the vibrational quenching cross section for ThO~(X,~$\nu=1$) to be $(7.9 \pm 2.7) \times 10^{-19}$~cm$^{-2}$ at 800~mK. Finally, we observe indirect evidence for ThO (X, $\nu=0$)--$^3$He van der Waals complex formation, and measure the 3-body recombination rate constant to be $\Gamma_3 = (8 \pm 2) \times 10^{-33}$~cm$^6$s$^{-1}$ at 2.4~K. The stability of the ground Th ($^3$F$_2$) state, metastable Th ($^3$P$_0$) state, and vibrational excited ThO (X, $\nu=1$) state provides data on anisotropic interactions in new systems and opens up the possibility for further studies and experiments, including trapping.Physics
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Campbell-Robson, Stephen. "A study of charm production in deep inelastic scattering in e'+p collisions." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388016.
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Luxford, Thomas Frederick Murray. "The stereodynamics of the inelastic collisions of NO(A2Σ+) with atoms and molecules." Thesis, Heriot-Watt University, 2017. http://hdl.handle.net/10399/3318.
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Please note that the equations are not displaying correctly below. Please see the full text instead. A newly constructed crossed molecular beam velocity map imaging experiment is used to study vector correlations for the rotationally inelastic collisions of NO(A2Σ+) with a range of atoms and diatomic molecules. Measurements are made of the differential cross section (DCS), and the { }2 +qA (θ) moments. Where possible, the experimental vector correlations are compared to the results of quantum scattering (QS) calculations performed on literature ab initio potential energy surfaces (PESs). Collisions of NO(A) with Ar and Ne lead to distinct features in the DCS, with a sharp, forward-scattered peak caused by scattering through the attractive region of the PES, and broader, higher-angle rotational rainbow peaks caused by scattering through the repulsive region of the PES. Sharp, angle-dependent fluctuations are observed in the { } 2 + qA (θ) moments. While there is generally good agreement between the experimental and QS results, deviations in the QS DCS highlight inaccuracies in the literature PESs. Collisions of NO(A) with He are controlled entirely through interactions on the repulsive region of the PES. Excellent agreement between experiment and QS calculations was found for both the DCS and {2} q+ A (θ) moments, showing that the literature PES is accurate. Collisions of NO(A) with D2 produced results similar to He, showing that the uncalculated NO(A)-D2 PES is similar to the NO(A)-He PES. Differences in the experimental results for the two systems were used to provide details on the differences between the two PESs. DCSs and {2} q+ A moments are successfully recorded for the collisions of NO(A) with N2, O2 and CO as a function of rotational excitation of the unobserved partner. Trends in the DCSs for different degrees of rotational energy transfer to the unobserved collision partner are found to be consistent with collisions with the repulsive region of the PES leading to quenching collisions, rather than rotational energy transfer.
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Sirmas, Nick. "Dynamics and Stability of Shock Waves in Granular Gases Undergoing Activated Inelastic Collisions." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36568.
Full textAbstract:
The present work investigates the dynamics and stability of shock waves in granular gases. The problem was modelled for a piston propagating into a system of disks that can undergo inelastic collisions if an impact threshold is exceeded. The model was addressed numerically at the microscopic and macroscopic levels. The molecular dynamics methodology employed the Event-Driven Molecular Dynamics method, and the continuum model was formulated using the Navier-Stokes equations for granular gases with the transport terms of Jenkins and Richman and a modified cooling rate term.
The inviscid steady state shock structure was derived and analyzed. The results indicated that a relaxing shock structure is expected for sufficiently strong shock waves. Beyond this limit the structure was shown to be independent of the initial energy, a finding similar to the strong shock approximation in molecular gases.
One-dimensional simulations demonstrated that the molecular dynamics and continuum models yield similar evolutions and structures of the shock wave, validating the continuum description of this study. Two-dimensional results showed that sufficiently strong shock waves can exhibit multi-dimensional instability with high density non-uniformities and convective rolls within the structure, with the size of instabilities shown to scale with the relaxation length of the shock structure. Instabilities were observed with the continuum description only with the inclusion of statistical fluctuations to density mimicking the molecular model. The cases that were unstable were shown to be in a regime whereby statistical fluctuations can become important, following the description for this regime by Bird.
Based on these findings, it is proposed that unstable shock behaviour can be observed for highly dissipative shock waves that yield short relaxation length scales, where fluctuations become important. The current work may shed light on unstable shock behaviour observed in dissipative gases, having implications for both granular media and molecular gases.
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Oliver, Katie Rosemarie. "Measurement of high Q² charged-current deep inelastic scattering with polarised positron beams using the ZEUS detector at HERA." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589602.
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This thesis presents measurements of charged current deep inelastic scattering cross sections in e+p collisions with longitudinally polarised positron beams. The measurements are based on data taken by the ZEUS detector at the HERA collider during the 2006-2007 run- ning period. The data sample has an integrated luminosity of 132 pb-1 and was taken at a centre-of-mass energy of 318 GeY. The total cross section has been measured at positive and negative values of the longitu- dinal polarisation of the positron beam (Pe). In addition, the single differential cross sections dδ / dQ2, dδ / dx and dδ / dy have been measured for Q2 > 200 Ge y2, also using both positively and negatively polarised positron beams. The reduced cross section has been measured in nine bins of Q2 in the kinematic range 280 < Q2 < 30000 Gey2 and 0.0078 < x < 0.42. The results are compared against the descriptions provided by the CTEQ6.6, MSTW 2008, HEARPDF1.0 and ZEUS-JETS PDFs. In general, the measured cross sections are well described by these predictions. Based on the measurement of the total cross section as a function of the polarisation of the positron beam, a lower limit on the mass of a hypothetical right-handed W boson has been extracted from the upper limit of the cross-section at Pe = -1. This limit is complementary to the limits obtained from direct searches (for example at CDF and D0) because the limit presented herein is for a space-like vV, whereas for direct searches, the limit on the mass of a time-like W boson is obtained. The results of this analysis have been published and have been included ill the determination of the HERAPDF theoretical prediction and also in HI and ZEUS combined results.
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Mowrey, Richard Carlton. "Theoretical studies of inelastic molecule-surface and resonant electron-atom and electron-molecule scattering /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu148725958026243.
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Spratt, David James. "Electron loss and excitation in atom-atom collisions." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287429.
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Keksis, August Lawrence. "N/z equilibration in deep inelastic collisions and the fragmentation of the resulting quasiprojectiles." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5886.
Full textAbstract:
When target and projectile nuclei have a difference in neutron to proton ratio (N/Z),
the quasiprojectiles formed in a deep inelastic collision (DIC) should have a mean
N/Z between the N/Z of the target and the N/Z of the projectile, depending on the
amount of N/Z equilibration that occurred. Data from six reaction systems at two
beam energies (32 and 45 MeV/nucleon) were collected. The systems in order of
increasing difference between target and projectile N/Z (shown in parentheses) are
40Ar + 112Sn (âÂÂN/Z = 0.018), 48Ca + 124Sn (âÂÂN/Z = 0.080), 48Ca + 112Sn (âÂÂN/Z
= 0.160), 40Ca + 112Sn (âÂÂN/Z = 0.240), 40Ar + 124Sn (âÂÂN/Z = 0.258) and 40Ca +
124Sn (âÂÂN/Z = 0.480).
The quasiprojectile N/Z was determined by two techniques. The first technique
used the isotopically resolved fragments to reconstruct the quasiprojectile N/Z. The
second technique, developed in this thesis, used fragment yield ratios and a simple
equation to simultaneously fit all six systems to determine the quasiprojectile N/Z.
Simulations and a filter of the FAUST (Forward Array Using Silicon Technology) acceptance
were used to calculate neutron loss; this accounted for the difference between
the two techniques.
To study the fragmentation of quasiprojectiles the fragment yields were used to
calculate the isobaric, isotopic, fractional and mean N/Z yields. The results showed
that as neutron richness increased, more neutron-rich fragments were produced. In addition observation showed evidence for an inhomogeneous distribution of N/Z between
the light charged particles (LCPs Z less than 3) and intermediate mass fragments
(IMFs Z greater than 2).
The theoretical results, which used different values of the symmetry energy, were
compared to experimental data to determine which symmetry energy best represents
the experimental data. The comparison showed the experimental data was the overall
best fit with a lower value of the symmetry energy. These results were not conclusive
and further investigation is required.
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Jin, Zhong. "The perturbative and non-perturbative QCD effects in the azimuthal distribution of hadron jets observed in muon deep inelastic scattering /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9724.
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Kluge, Thomas. "Measurement and QCD analysis of event shape variables in deep inelastic electron proton collisions at HERA." Hamburg : DESY, 2004. http://deposit.d-nb.de/cgi-bin/dokserv?idn=971990387.
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Goldberg, Noah Tribe. "Reactive and inelastic H + D₂ collisions : classical recoil, quantum interference, and the tug-of war mechanism /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Chadwick, Helen J. "Angular momentum polarisation effects in inelastic scattering." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:474b04fa-4f50-4618-88ab-c85878723f2a.
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In this thesis, a joint experimental and theoretical investigation of the vector properties that describe the inelastic scattering of a diatomic radical with an atomic collision partner is presented. A particular emphasis is placed on those correlations that include the final rotational angular momentum, j', of the radical. The depolarisation of both NO(A) and OH(A) brought about through collisions with krypton has been studied, providing a measure of the j-j' correlation, where j is the initial rotational angular momentum associated with the diatom. The total depolarisation cross- sections for both collisional disorientation and disalignment have been measured using quantum beat spectroscopy, and modelled theoretically using quasi-classical trajectory (QCT) calculations. The agreement between experiment and theory for NO(A)-Kr is excellent, but is not observed for OH(A)-Kr under thermal conditions. This has been attributed to the importance of electronic quenching in OH(A)-Kr. The depolarisation cross-sections have also been determined at a higher collision energy for OH(A)-Kr where electronic quenching is less significant, and the experimental results are in better agreement with those obtained theoretically. The NO(A)-Kr depolarisation cross-sections fall with increasing rotational quantum number, N, whereas for OH(A)-Kr, they exhibit less of an N dependence. This trend is mirrored in the elastic depolarisation cross-sections, which have also been determined experimentally for OH(A)-Kr. The significantly attractive and anisotropic nature of the OH(A)-Kr potential energy surface (PES) accounts for these observations. The j-j' correlation is extended to include the initial (relative) velocity (k) in a new theoretical treatment of the k-j-j' correlation. The formalism developed is used with the results from the QCT calculations for NO(A)-Kr and OH(A)-Kr to provide further insight into the mechanism of depolarisation in the two systems. Collisions of NO(A) with krypton do not cause significant depolarisation due to their impulsive nature, and the projection of j onto the kinematic apse is conserved. In contrast, collisions of OH(A) with krypton effectively randomise the direction of j, again showing the influence of the anisotropic and attractive nature of the PES. However, the projection of j onto the kinematic apse is still conserved. The inelastic scattering of NO(X) with argon and krypton has also been investigated, using a crossed molecular beam apparatus. The initial Λ-doublet state of the NO(X) was selected using hexapole focussing, and the products of the collision detected using velocity mapped ion imaging. The state to state differential cross-sections (equivalent to the k-k' correlation, where k' is the final relative velocity) have been measured for collisions which conserve the initial spin-orbit level of the NO(X) with krypton. The same parity dependent effects were seen as have been observed previously for NO(X)-Ar. The collision induced alignment (equivalent to the k-k'-j' correlation) of NO(X) as a result of scattering with argon has also been determined experimentally. The results can be explained classically by considering the conservation of the projection of j onto the kinematic apse.