Dissertations / Theses: 'Ions'

1

Pickles, Raymond J. "Intracellular calcium ions in epithelial ion transport." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307103.

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2

Voulot, Didier. "An experimental study of state selective electron capture by state prepared low energy (<25 keV amu'-'1) ions in atomic and molecular hydrogen." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325995.

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3

Campbell, Corey Justin. "Trapping, laser cooling, and spectroscopy of Thorium IV." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/48973.

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Application of precision laser spectroscopy and optical clock technology to the ground and metastable, first excited state of the ²²⁹Th nucleus at < 10 eV has significant potential for use in optical frequency metrology and tests of variation of fundamental constants. This work is a report on the development of required technologies to realize such a nuclear optical clock with a single, trapped, laser cooled ²²⁹Th³⁺ ion. Creation, trapping, laser cooling, and precision spectroscopy are developed and refined first with the naturally occurring isotope, ²³²Th. These technologies are then extended to laser cooling and precision laser spectroscopy of the electronic structure of ²²⁹Th³⁺. An efficient optical excitation search protocol to directly observe this transition via the electron bridge is proposed. The extraordinarily small systematic clock shifts are estimated and the likely extraordinarily large sensitivity of the clock to variation of the fine structure constant is discussed.

4

Choi, Jong-Ho Okumura Mitchio Okumura Mitchio. "Infrared spectroscopy of molecular ions and ion-solvent clusters /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-09252007-09111.

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5

Newson, Karl Adrian. "The properties of gas-phase multiply charged ions." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324990.

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6

MAAZOUZ, MOSTAFA. "Formation des ions negatifs lors de collisions ions/atomes-surfaces." Paris 11, 1997. http://www.theses.fr/1997PA112053.

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Ce travail de these porte sur une etude experimentale de la formation d'ions negatifs lors de la diffusion d'ions ou atomes de h, o, f et cl sur des surfaces metalliques (mg, al et ag) et de silicium. La fraction d'ions negatif d'hydrogene mesuree sur les differents metaux est en bon accord avec les calculs cam. L'analyse theorique montre que la difference entre les fractions observees doit etre reliee aux caracteristiques de la bande de valence des metaux. Ces mesures ont ete etendues au cas de la formation d'ions negatifs d'oxygene, de fluor et de chlore. Une comparaison avec des modeles theoriques est presentee. Les fractions d'ions negatifs d'hydrogene et d'oxygene mesurees sur une cible de si sont de meme ordre de grandeur que celles obtenues sur l'aluminium. En outre, un effet dynamique de la capture d'electron a ete observe. Le transfert de charge dans ce cas est interprete en terme de transition non resonante, impliquant les bandes etroites liees aux etats de surface du si. Une etude de la formation de l'ion negatif d'hydrogene a ete realisee sur des surfaces de mg et al exposees a l'oxygene. Aux faibles expositions, le transfert de charge est interprete en terme de competition entre deux effets opposes: effet non local (reduction du travail de sortie) et effet local (modification de la structure electronique sur les sites d'adsorption de l'oxygene). Aux fortes expositions, la diffusion sur un solide ionique est a considerer. La forte production de l'ion negatif h dans ce cas est attribuee a un processus de capture d'electron non resonant impliquant le niveau de l'ion negatif de l'hydrogene et les sites des anions de l'oxyde

7

Avkiran, Metin. "Pathophysiological roles, pharmacological inhibition and cellular regulation of the cardiac sarcolemmal sodium/hydrogen exchanger." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601638.

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8

Shepherd, Juliet. "Theoretical studies of slow collisions : elastic electron scattering from positive ions, charge transfer in one-electron ion-ion systems and mutual neutralization of Hâ»/Dâ» and Hâºâ‚‚." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366574.

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9

Donohoe, Timothy J. "Chiral oxonium ions." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314854.

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10

Bäckström, Erik. "LIfetimes measurement states in ions at an ion storage ring." Licentiate thesis, Stockholms universitet, Fysikum, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-67024.

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11

Russell, Elspeth. "Ions and ion transport mechanisms in the developing chick embryo." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287301.

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12

Fisher, Zachary (Zachary Kenneth). "Shuttling of ions for characterization of a microfabricated ion trap." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78510.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 65-67).
In this thesis, I present experimental results demonstrating the characterization of a planar Paul trap. I discuss the theory of ion trapping and analyze the voltages required for shuttling. Next, the characteristics of a digital-to-analog converter (DAC) are calibrated, and this instrument is integrated into trapping experiments to test the viability of the analytic model. Combining theory with the capabilities of the DAC, I calculate that the new experimental system is capable of 3 nm-precision control of the ion. Taking advantage of this ion control, I present initial results for a lock-in micromotion detection method which minimizes stray fields around an ⁸⁸Sr+ ion using Fourier analysis on the ion fluorescence to detect resonance at the secular frequencies. This method drives the ion oscillator across resonance using a superimposed radiofrequency electric field, which allows for off-axis field measurements as well as trap characterization. With this method, the secular frequencies of the trap are measured and are observed to fall within 3.50[sigma] of the analytic prediction.
by Zachary Fisher.
S.B.

13

MANOSSO, HELENA C. "Desenvolvimento de eletrodos de troca iônica eletroquímica para o tratamento de rejeitos contendo íons crômio ou césio." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11439.

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Made available in DSpace on 2014-10-09T12:51:56Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:07:55Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

14

Xu, Yaodong. "Applications of mass spectrometric techniques to charge-transfer processes and cluster ion reactions." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/26208.

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15

Pradhan, Atul D. (Atul Deep). "Photodissociation of molecular ions and low-energy collisions of atoms and ions." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/17317.

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16

Ma, Yiu Wa. "Fixed bed removal of heavy metal ions by chelating ion exchange." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491880.

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Column runs with varied operation conditions of flowrate, feed concentration and particle size have been conducted to observe the sorption of nickel, copper and zinc by the chelating resin. They all show a typical constant-pattern, steep curve in the first part of the breakthrough curve and the slope would dramatically reduce at a breakpoint such that it would take extremely long time to reach 100% breakthrough level. ~ The Modified Bed Depth Service Time (BDST) model incorporated with a timedependent bed capacity has been used together with the Empty Bed Residence Time (EBRT) model to analyze the fixed bed performance under different operating conditions. The Homogeneous Surface Diffusion Model (HSDM) and the Shrinking Core Diffusion . Model (SCDM) have been applied to- model the fixed bed performance. Due to the dramatic change in the slope, the first and second parts of the breakthrough curves need to be modeled separately. Comparing the two models, SCDM is more appropriate to explain the sorption of metal ions into the chelating resin. The research has suggested the existence of a Na-loaded outer shell and a H-loaded inner core in the chelating resin. When the moving boundary progresses from the outer shell into the inner core, there is a remarkable change in the ion exchange process, resulting in different kinetics. This explains the sharp change in the slope of the experimental breakthrough curves. A new version of SCDM has been developed to model the progression of the moving boundary inside the resin for the successive resin layers along the whole resin column so as to predict the column' s solid and liquid phase concentration profiles. The new SCDM has. the flexibility of varying the portion of the outer shell so that the behavior of resins with different resin Na contents can be predicted.

17

Kelly, Gregory J. "Negative ion production from positive ions incident in a metal vapour." Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/22416.

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18

Ashman, A. S. "Laser spectroscopy of molecular ions in an Ion Cyclotron Resonance apparatus." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234408.

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19

Beckert, Marco. "Photodissociation dynamics of halogens and halogen-ions studied by ion imaging." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274674.

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20

Labaziewicz, Jarosław. "High fidelity quantum gates with ions in cryogenic microfabricated ion traps." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45167.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 135-146).
While quantum information processing offers a tantalizing possibility of a significant speedup in execution of certain algorithms, as well as enabling previously unmanageable simulations of large quantum systems, it remains extremely difficult to realize experimentally. Recently, fundamental building blocks of a quantum computer, including one and two qubit gates, teleportation and error correction, were demonstrated using trapped atomic ions. Scaling to a larger number of qubits requires miniaturization of the ion traps, currently limited by the sharply increasing motional state decoherence at sub-100 [mu]m ion-electrode distances. This thesis explores the source and suppression of this decoherence at cryogenic temperatures, and demonstrates fundamental logic gates in a surface electrode ion trap. Construction of the apparatus requires the development of a number of experimental techniques. Design, numerical simulation and implementation of a surface electrode ion trap is presented. Cryogenic cooling of the trap to near 4 K is accomplished by contact with a bath cryostat. Ions are loaded by ablation or photoionization, both of which are characterized in terms of generated stray fields and heat load. The bulk of new experimental results deals with measurements of electric field noise at the ion's position. Upon cooling to 6 K, the measured rates are suppressed by up to 7 orders of magnitude, more than two orders of magnitude below previously published data for similarly sized traps operated at room temperature. The observed noise depends strongly on fabrication process, which suggests further improvements are possible. The measured dependence of the electric field noise on temperature is inconsistent with published models, and can be explained using a continuous spectrum of activated fluctuators. The fabricated surface electrode traps are used to demonstrate coherent operations and the classical control required for trapped ion quantum computation. The necessary spectral properties of coherent light sources are achieved with a novel design using optical feedback to a triangular, medium finesse, cavity, followed by electronic feedback to an ultra-high finesse reference cavity.
(cont.) Single and two qubit operations on a single ion are demonstrated with classical fidelity in excess of 95%. Magnetic field gradient coils built into the trap allow for individual addressing of ions, a prerequisite to scaling to multiple qubits.
by Jarosław Labaziewicz.
Ph.D.

21

Miller, Catherine Elizabeth. "On the stability of complex ions in ionic liquid Ion sources." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98808.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 139-141).
Ionic liquids are molten salts at room temperature that consist of positive and negative ions. These liquids can be used in electrosprays to produce ion beams. Ionic liquid ion source (ILIS) beams typically consist of single ions and solvated ions. It has been observed that solvated ions are not always stable and can break up into lighter ions midflight. Past experiments show that the stability of solvated ions depends on the molecular composition of the ionic liquid. Based on these results, it has been hypothesized that the stability of solvated ions increases with increasing molecular complexity of the ions. The focus of this work is to test this hypothesis by characterizing ionic liquids of different molecular complexities under controlled conditions. A time of flight mass spectrometer and a retarding potential analyzer were developed specifically for this purpose. The ion beam composition and energy distribution were measured at various temperatures and source voltages for each ionic liquid. With some exceptions, the observed trend was in agreement with the results of past experiments and with the hypothesis. The exceptions to the expected trend may have resulted from the limitations of the detectors. The data from this work can be used to test the hypothesis with moderate confidence. Future study requires improvements to the detectors, namely the retarding potential analyzer, so that the hypothesis can be evaluated more conclusively.
by Catherine Elizabeth Miller.
S.M.

22

De, Palatis Michael V. "Production of cold barium monohalide ions." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50251.

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Ion traps are an incredibly versatile tool which have many applications throughout the physical sciences, including such diverse topics as mass spectrometry, precision frequency metrology, tests of fundamental physics, and quantum computing. In this thesis, experiments are presented which involve trapping and measuring properties of Th³⁺. Th³⁺ ions are of unique interest in part because they are a promising platform for studying an unusually low-lying nuclear transition in the 229Th nucleus which could eventually be used as an exceptional optical clock. Here, experiments to measure electronic lifetimes of Th³⁺ are described. A second experimental topic explores the production of sympathetically cooled molecular ions. The study of cold molecular ions has a number of applications, some of which include spectroscopy to aid the study of astrophysical objects, precision tests of quantum electrodynamics predictions, and the study of chemical reactions in the quantum regime. The experiments presented here involve the production of barium monohalide ions, BaX⁺ (X = F, Cl, Br). This type of molecular ion proves to be particularly promising for cooling to the rovibrational ground state. The method used for producing BaX⁺ ions involves reactions between cold, trapped Ba⁺ ions and neutral gas phase reactants at room temperature. The Ba⁺ ion reaction experiments presented in this thesis characterize these reactions for producing Coulomb crystals composed of laser cooled Ba⁺ ions and sympathetically cooled BaX⁺ ions.

23

Türp, David [Verfasser]. "Dendronized ions / David Türp." Mainz : Universitätsbibliothek Mainz, 2012. http://d-nb.info/1025995759/34.

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24

Jonathan, P. "Translational spectroscopy of ions." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637445.

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Translational spectroscopy is used to examine the keV collision reactions of small ions with thermal neutral species. State selective single electron capture data for Ar²⁺ on rare gas and small molecular targets is interpreted in terms of calculated reaction windows and charge exchange channels. Evidence for double ionisation of hydrocarbon targets is presented. Dissociation of H_2⁺ occurs predominantly via direct electronic excitation. A second two collision process involving H₂ intermediates accounting for 5% of H^+ fragment yield is examined; H^- fragments arise from dissociative capture of H_2 intermediates. Approximate relative cross sections, and translational energy release distributions, for H^+ and H^- from the dissociation of H_2^+ in H_2, rare gases and hydrocarbons are measured. An investigation of E/2 mass spectra, involving consecutive charge stripping and electron capture reactions of organic ions, elucidates the parameters governing the reproducibility of spectra. A short study involving benzene, 1,5-hexadiyne, methylbenzene and nitrobenzene demonstrates the effects found. Cations consisting of a rare gas atom associated to a small molecule or radical, are investigated by means of the thermal ion molecule reactions by which they are formed in the ion source of the spectrometer, and their subsequent keV collision reactions. For diatomic dications of this form, charge stripping and charge separation data, discussed in terms of semi empirical potential energy curves, yields valuable information as to ion structure and stability. The design of a novel translational energy spectrometer, capable of an ultimate resolving power of 3 meV on product ion spectra at 500 eV ion translational energy, is described. Matrix calculations for projectile trajectories are performed. A simple theoretical model for inelastic scattering permits the evaluation of the effect of collisional broadening on the resolving power of the instrument.

25

Carlin, N. M. "Photodetachment of negative ions." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411056.

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26

Ferrigato, Alberto. "Spectroscopy of coupled ions." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277517.

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27

Angel, Laurence Ambrose. "Reactions of atmospheric ions." Thesis, University of Sussex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297548.

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28

Weisskoff, Robert Mark. "Detecting single, trapped ions." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/68230.

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29

Lentz, Nicholas B. "Electrospray ionization mass spectrometry from cluster ions to toxic metal ions in biology /." [Ames, Iowa : Iowa State University], 2007.

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30

May, Paul W. "The energies of ions, electrons and neutral in reactive ion etching plasmas." Thesis, University of Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303946.

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31

Back, Tekla. "Laser spectroscopy of highly charged ions using an electronic beam ion trap." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711594.

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32

Jonah, Tosin Mobolaji. "Selective Sensing of Ions and Ion Pairs of Environmental and Forensic Significance." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3498.

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Dual-host combinations of cation and anion sensors have unique potential for selective detection of ion pairs, such as NH4NO3, via solvent extraction. Selective sensors for NH4+ and NO3- were synthesized and used together for ion-pair sensing of ammonium nitrate both in organic solvents (using Bu4N+NO3 - and NH4+PF6-) and in extraction of NH4NO3 from water into dichloromethane. A fluorescent sensor for NH4+ based on 1,3,5-triethylbenzene shows remarkable binding and sensing selectivity for NH4+ vs. K+. Fluorescence and 1H-NMR titrations reveal surprising differences in sensing properties and binding constants for the tris-(3,5-dimethyl)pyrazole vs. the tris(3,5-diphenyl)pyrazole. The role of ion pairing and solvation is revealed by X-ray and theoretical DFT studies. We have also demonstrated a unique dual-host extraction-based ion-pair sensing paradigm using Förster Resonance Energy Transfer (FRET), showing selectivity for NH4NO3. The fluorescence emission of the NH4+ sensor tris-(3,5-dimethyl)pyrazole (305-340 nm), is compatible with the excitation wavelength of the dansyl fluorophore of the nitrate sensor 1,3,5-Tris-(5-dimethylamino-1-naphthalenesulfonamido)methyl]-2,4,6-triethylbenzene, thus resulting in FRET emission upon combined use of these two sensors for the NH4NO3 ion pair. Contact of dichloromethane solutions containing the two hosts with aqueous solutions of NH4NO3 (1 x 10-5 M to 1 x 10-4 M ), resulted in FRET fluorescence enhancements at 510 nm, with increasing concentrations of NH4NO3, while NaNO3, KNO3, NaCl and KCl showed only minimal fluorescence responses, under identical conditions. The ability of the tris-pyrazole to bind cations, such as NH4+, was also exploited in a detailed fluorescence and 1H-NMR Ln(III), binding study using tris-pyrazoles with varying substitution patterns. The dependence of fluorescence responses on pyrazole substitution that had been observed for NH4+ was also observed for different Ln(III), indicating the significant role of ion pairing for Ln(III) binding and fluorescence sensing. Likewise, the tris-dansyl nitrate receptor, in its deprotonated form, was also found to be an efficient Hg(II) fluorescent sensor. An X-ray crystal structure showed the ability of the trianionic version of this receptor to bind three Hg(II) atoms, also containing three CH3COO- counteranions. The X-ray crystal structure of the same receptor with HgCl2 gave a 2:1 complexation pattern, with one Hg atom complexed by two bis-deprotonated receptor molecules

33

Matsushita, Michio. "Experimental and Theoretical Studies of Organic High-Spin Ions and Extremely Non-Rigid Ions." 京都大学 (Kyoto University), 1992. http://hdl.handle.net/2433/168825.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第4984号
理博第1381号
新制||理||770(附属図書館)
UT51-92-J31
京都大学大学院理学研究科化学専攻
(主査)教授志田忠正, 教授廣田襄, 教授梶本興亜
学位規則第4条第1項該当

34

Ahrika, Abdelkader. "Réactivité nucléophile des ions polysulfures ; génération et caractérisation des ions polyséléniures dans le diméthylacétamide." Tours, 2000. http://www.theses.fr/2000TOUR4015.

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L'étude de la réactivité nucléophile des ions polysulfures s 3. Vis-à-vis des halogénures d'alkyle RX et des S-phenyl thioesters RC(O)SPH a été mise en œuvre par spectroélectrochimie dans le N,N-diméthylacétamide. Les ions RS x ($$x 5) initialement issus de la substitution (Sn2) des ions S(-1/3) réagissent ensuite sur les dérivés RX pour conduire a des mélanges RSzR ($$z 3,5 en solution diluée ; $$z 3,8 au niveau préparatif). Avec les substrats RC(O)SPH, les ions RC(O)S / RC(O)S 2 en équilibre sont les produits de substitution alors que le nucléofuge se trouve sous la forme PhS 4. La cinétique des réactions les plus lentes [RX + S3 ; RC(O)SPh + S3] est d'ordre 2 par rapport aux ions S3 dont le dimère S6 2 est vraisemblablement l'agent nucléophile dans les solutions S(1/3). L'électroréduction du sélénium déposé sur électrode d'or s'effectue en cinq étapes, dont les trois premières ont ete identifiées : elles conduisent successivement aux espéces colorées Se 8 2 , Se 6 2 , Se 4 2 d'après l'évolution des spectres d'absorption UV-VIS avec l'avancement des électrolyses. Une dissociation significative des ions Se 6 2 en radical-anion Se 3. N'est pas décelable en modifiant la température et la concentration des solutions anioniques. La stabilisation des polyséléniures organiques RSe x (x = 24) a été mise en évidence par deux approches : (i) réaction du sélénium sur les ions sélénolates RSe (R = PhCH2, Ph) ; (ii) réduction partielle des disélanes RSe2R par les ions Se 4 2 et Se 6 2 , conforme à une dismutation importante des entités RSe3 et RSe 4.

35

Palla, Veladri. "Heterometallic Interactions of d8-d10 Metal Ions in the Presence of +2 Cations." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/PallaV2007.pdf.

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36

Schmidt, Dirk Christoph. "Etude des défauts créés par implantation dans le silicium et de leur influence sur la diffusion du platine." Poitiers, 1998. http://www.theses.fr/1998POIT2343.

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Les recherches concernant le travail presente dans cette these d'universite ont ete effectuees dans trois pays differents de la communaute europeenne ; au laboratoire de metallurgie physique de l'universite de poitiers, au laboratoire du iv. Physikalisches institut de l'universite de gottingen (allemagne) et au laboratoire d'electronique de l'etat solide a l'institut royal de technologie de stockholm (suede). L'or et le platine sont des impuretes metalliques couramment employees dans l'industrie electronique pour controler la duree de vie des porteurs minoritaires dans les dispositifs de puissance a faible temps de commutation. Recemment, l'implantation aux ions legers a montre qu'elle pouvait etre utilisee comme methode de substitution a la diffusion des impuretes en raison des divers avantages qu'elle presente comme par exemple la reproductibilite, la possibilite de changer les caracteristiques electriques de la diode a la fin des differentes etapes de fabrication et le fait que la temperature de la diode est beaucoup plus basse durant l'implantation que pendant la diffusion thermique. La combinaison implantation-diffusion est egalement proposee comme une methode alternative car elle permet de reduire de facon notable la temperature de diffusion des impuretes et de controler precisement la position et la concentration des centres de recombinaison. Dans cette these, l'influence des defauts, introduits par implantation ionique ou irradiation aux electrons, sur la diffusion du platine a ete etudie. La principale methode de caracterisation utilisee est la spectroscopie transitoire des niveaux profonds ou dlts (deep level transient spectroscopy). Cette methode permet de determiner les profils de concentration des defauts ainsi crees et du platine diffuse. On observe que les defauts, produits par l'irradiation aux electrons ou par implantation ionique de protons ou de particules alpha, sont decores par le platine. Ce resultat peut etre explique en invoquant les mecanismes de diffusion de type kick-out et de frank-turnbull. Au-dessous d'une temperature de diffusion de 600c on ne detecte aucun atome de platine diffuse. Cependant de nouveaux defauts, lies a la presence d'interstitiels, surgissent dans le spectre dlts. Enfin des implantations de silicium et des irradiations aux electrons dans des substrats a temperatures eleves ont ete realisees afin de mieux comprendre la nature des defauts crees par implantation/irradiation.

37

Reinhard, Björn M. "Chemistry of microsolvated metal ions." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969739273.

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38

Lindqvist-Reis, Patric. "Structure of solvated matal ions." Doctoral thesis, KTH, Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2996.

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The structure of the solvated group 3 ions scandium(III),yttrium(III) and lanthanum(III), has been determined in aqueoussolution and in some oxygen donor solvents, and compared withthe hydrated group 13 ions gallium(III) and indium(III). Acombination of X-ray absorption fine structure (XAFS), largeangle X-ray scattering (LAXS), crystallography and vibrationspectroscopy has been used for the structure studies of thehydrated ions and their dimethylsulfoxide andN,N´-dimethylpropylene urea solvates in solution and inthe solid state. For the hexahydrated gallium(III) andindium(III) ions in solution, the metal-oxygen distances werefound to be 1.959(6) Å and 2.131(7) Å to the firsthydration shell, and 4.05(1) and4.13(1) Å, respectively,to fairly well-defined second hydration shells containing abouttwelve water molecules. The hydration structure of thecalcium(II) ion was studied by combining EXAFS and LAXS studiesand Molecular Dynamics simulations. The biochemically importantcalcium ion was found to be octahydrated in aqueous solutionwith abroad and asymmetric distribution of the Ca-O bonddistances around the mean value 2.46(1) Å. Also theyttrium(III) ion was found to be octahydrated in aqueoussolution with an asymmetric distribution of the Y-O bonddistances around a mean value of 2.366(5) Å. The mean Y-Odistance in the eight-coordinated compound([(H₂O)₄Y(µ-OSO₂CH₃)₂]CH₃SO₃)_nis 2.35 Å. The hydration of thelanthanum(III) ion was consistent with a coordination of ninewater molecules with the La-O distances 6´2.52(2) and3´2.65(3) Å, probably with the oxygen atoms forming atricapped trigonal prism. Also for the hydrated scandium(III)ion in aqueous solution, a capped trigonal prismaticcoordination figure, with the mean Sc-O bond distance 2.17(1)Å to the water molecules in the prism, gives the bestdescription of the structure. There seems to be 2 or 3 cappingwater molecules, but the Sc-O distances in the range 2.3-2.5Å are not well-defined. The crystal structure of [Sc(H₂O)₈](CF₃SO₃)₃, which at ambient temperature is isomorphous withthe [M(H₂O)₉](CF₃SO₃)₃compounds with a series of nonahydrated tricappedtrigonal prismatic lanthanide(III) ions, was studied attemperatures down to 100 K. One capping water molecule wasfound to be missing in the[Sc(H₂O)₈](CF₃SO₃)₃structure, causing a displacement of the scandiumionabout 0.2 Å from the centre of the trigonal prism. Aredetermination of the isomorphous[Yb(H₂O)_n](CF₃SO₃)₃structure was made, resulting in n » 8.6 forthe slightly larger Yb(III) ion. Octahedrally coordinatedscandium(III) ions were found in the crystal structures of[Sc(H₂O)₆][Sc(CH₃SO₃)₆]and trans-[Sc(H₂O)₄Cl₂]Cl×2H₂O, with mean Sc-O distances of 2.08 and 2.11Å, respectively. The scandium(III) ion was found to beoctahedrally six-coordinated in dimethylsulfoxide solution,with the mean Sc-O distance 2.09 Å, and in the solid[Sc(dmso)₆]I3 compound with Sc-O 2.075(3) Å. The largeryttrium(III) ion is eight-coordinated in solution with the meanY-O distance 2.36(1) Å. In the crystal structure of[Y(dmso)₈]I3 the mean Y-O distance is 2.36 Å, while theY-O distance to the two dimethylsulfoxide ligands in [Y(H₂O)₆(dmso)₂]Cl₃is only 2.27 Å and the mean Y-O waterdistance 2.37 Å. Also lanthanum(III) in dimethylsulfoxidesolution was found to form an eight-coordinated complex withthe mean La-O distance 2.50(2) Å. TheN,N´-dimethylpropylene urea solvated scandium(III),yttrium(III) and lanthanum(III) ions were found to have thecoordination number six, six and seven in solution,respectively, showing that steric ligand-ligand repulsioneffects are controlling the solvation numbers in aproticsolvents for these ions with noble gas electronconfiguration.

39

Skupinski, Marek. "Nanopatterning by Swift Heavy Ions." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7183.

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Abstract:

Today, the dominating way of patterning nanosystems is by irradiation-based lithography (e-beam, DUV, EUV, and ions). Compared to the other irradiations, ion tracks created by swift heavy ions in matter give the highest contrast, and its inelastic scattering facilitate minute widening and high aspect ratios (up to several thousands). Combining this with high resolution masks it may have potential as lithography technology for nanotechnology. Even if this ‘ion track lithography’ would not give a higher resolution than the others, it still can pattern otherwise irradiation insensitive materials, and enabling direct lithographic patterning of relevant material properties without further processing. In this thesis ion tracks in thin films of polyimide, amorphous SiO₂ and crystalline TiO₂ were made. Nanopores were used as templates for electrodeposition of nanowires.

In lithography patterns are defined by masks. To write a nanopattern onto masks e-beam lithography is used. It is time-consuming since the pattern is written serially, point by point. An alternative approach is to use self-assembled patterns. In these first demonstrations of ion track lithography for micro and nanopatterning, self-assembly masks of silica microspheres and porous alumina membranes (PAM) have been used.

For pattern transfer, different heavy ions were used with energies of several MeV at different fluences. The patterns were transferred to SiO₂ and TiO₂. From an ordered PAM with pores of 70 nm in diameter and 100 nm inter-pore distances, the transferred, ordered patterns had 355 nm deep pores of 77 nm diameter for SiO₂and 70 nm in diameter and 1,100 nm deep for TiO₂. The TiO₂ substrate was also irradiated through ordered silica microspheres, yielding different patterns depending on the configuration of the silica ball layers.

Finally, swift heavy ion irradiation with high fluence (above 10¹⁵/cm²) was assisting carbon nanopillars deposition in a PAM used as template.

40

Phillips, Rosemary Helen. "Metal ions and Helicobacter pylori." Thesis, King's College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408125.

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41

Antonsen, Carolina. "Surface scattering using KeV ions." Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/5393.

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42

Nagy, Jozsef Bordas. "Kilovolt collisions of small ions." Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/21086.

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43

Poteau, Xavier. "Fluorescent sensors for metal ions." Thesis, University of Central Lancashire, 2001. http://clok.uclan.ac.uk/21458/.

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Abstract:

The considerable current interest in the use of fluorescent molecules in molecular recognition is not new, but is one that has increased in importance in recent years due to their applications in many fields including trace analysis in chemistry and biochemistry. Using the "dual fluorescence" properties of TICT state compounds (Twisted Intramolecular Charge Transfer which gives an extra red-shifted emission band) and the key property of crown ether compounds which is their ability to complex ions, we designed and synthesised a range of new fluoroionophores and studied their photophysical behaviour towards a selection of alkaline and alkaline-earth metal ions. The new fluoroionophores (4-(i '-aza-4'-7'- 10 ,-i 3 '-tetraoxapentadecyl) benzonitrile, 4-( 1 '-aza-4'-7'- 10-i 3'-! 6'-pentaoxapentadecyl)benzonitrile, methyl-4- (1 '-aza-4'-7'-10'-13'-tetraoxapentadecyl)benzoate, 4'-N,N-(i "-aza-4",7",iO' ',l 3"- tetra oxapentadecyl)-3-hydroxyflavone and 4'-N,N-(l "-aza-4' ',7' ',lO", 13"- tetraoxapenta decyl)-3-methoxyflavone) have been shown to form TICT states upon excitation. The photophysics (absorption, emission, lifetimes) of these compounds are affected by the complexation of cations which reduce the donor character of the nitrogen belonging to the crown. The studied dications (Mg2 , Ca2 and Ba2') lead to larger spectral shifts and bigger values of the binding constant Ks than the studied monocations (Lie, Nat, K, CC) which can be interpreted in terms of a stronger electrostatic interaction between the nitrogen lone pair and the alkaline-earth metals than the alkali-metals. It appears that the selectivity demonstrated by these crown ethers towards the alkaline earth and alkali metals is not only explained by the "hole-size relationship" between the size of the crown ether cavity and the ionic mdii of the metal ions. The type of substituent on the phenyl of the azacrown ether has been shown to further influence the spectroscopic properties (shift of the absorption ansi emission bands). Nevertheless the photophysical properties of the azacrown ether derivatives studied does not show enhancement of the selectivity towards the studied metals on expansion of the delocalisation system. More complex mechanisms are in operation in flexible systems such as the azacrown derivatives used in this study geometry, conformation and rigidity all play roles in determining the binding strength and selectivity of these molecules.

44

Skupiński, Marek. "Nanopatterning by swift heavy ions /." Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7183.

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45

Brandefelt, Nicklas. "Resonant States in Negative Ions." Doctoral thesis, Stockholm : Univ, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-199.

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46

Jarvis, Vern Marshall. "Studies of molecular cluster ions." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/30074.

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47

McIntyre, Sara Anne. "Stereospecific cyclisations via episulphonium ions." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330069.

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48

Steinbach, Joerg. "Quantized motion of trapped ions." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313334.

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49

McNab, Iain Ross. "The spectroscopy of molecular ions." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329941.

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50

Ramsbottom, Catherine Anne. "Photoabsorption by atoms and ions." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239229.

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Dissertations / Theses on the topic 'Ions'

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