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Visar resultat 1 - 5 av 75 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Theoretical and Experimental Studies of the Formation of Ionized Gases in Spark Ignition Engines

    Författare :Raymond Reinmann; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Thermal Ionization; Calorimetry; Interferometry; Spark Ignition Engine; Current and Voltage Measurements; Engine Control.; fluid dynamics; Gases; plasmas; Gaser; plasma; fluiddynamik; Breakdown; Arc; Glow; Flame Ionization; Chemi-Ionization; Spark; Townsend; Fysicumarkivet A:1998:Reinmann;

    Sammanfattning : The processes that govern the formation, existence and consumption of ions in gases have been studied both experimentally and theoretically. The aim of the work is targeted at increasing the understanding of these phenomena in the working gases inside an engine. LÄS MER

  2. 2. Dissociation dynamics of highly excited molecules: Theory and Experiment

    Författare :Shabnam Oghbaie; Synkrotronljusfysik; []
    Nyckelord :Molecular dissociation; core-electron excitation; double ionization; femtoseconds molecular dynamics; Isomerization; symmetry breaking; momentum imaging; site-selective dissociation; butadiene; cyclopropane; nuclear dynamics; Auger decay;

    Sammanfattning : This thesis presents studies on dissociation of two model molecules: Butadiene and Cyclopropane. Tunable synchrotron radiation was used to ionize or excite the molecules in the gas phase, and the momentum correlation of the resulting fragment ions were measured using a 3D momenta coincident ion spectroscopy. LÄS MER

  3. 3. Structure and Dynamics of Core-Excited Species

    Författare :Oksana Travnikova; Maria Novella Piancastelli; Svante Svensson; Denis Ceolin; Pascal Lablanqui; Uppsala universitet; []
    Nyckelord :Physics; Synchrotron radiation; X-ray Photoelectron Spectroscopy XPS ; X-ray Absorption Spectroscopy XAS ; Resonant Auger Spectroscopy RAS ; Auger Electron Spectroscopy AES ; Energy-Selected Auger Electron PhotoIon COincidence ES-AEPICO ; core excitation; core ionization; linear free energy relationships LFER ; molecular-field splitting; substituent effects; nuclear dynamics; isomerization; Cl2; N2O; methane derivatives; allene; acetylacetone; Fysik;

    Sammanfattning : In this thesis we have performed core-electron spectroscopy studies of gas phase molecular systems starting with smaller diatomic, continuing with triatomic and extending our research to more complex polyatomic ones. We can subdivide the results presented here into two categories: the first one focusing on electronic fine structure and effect of the chemical bonds on molecular core-levels and the other one dealing with nuclear dynamics induced by creation of a core hole. LÄS MER

  4. 4. Ultrafast Photo-induced Reaction Dynamics of Small Molecules

    Författare :Malin Kadi; Jan Davidsson; Eva Åkesson; Sören Keiding; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; pump-probe spectroscopy; reaction dynamics; photodissociation; aryl halides; spin-orbit coupling; ab initio calculations; molecular dynamics; vibrational wavepackets; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : The main focus of this thesis is the investigation of the dissociation dynamics of aryl halides using femtosecond pump-probe spectroscopy. In the monohalogenated aryl halides, iodo-, bromo- and chlorobenzene, the rate of dissociation following excitation at 266 nm in the gas phase increased with increasing mass of the halogen atom. LÄS MER

  5. 5. Ionization of large molecules with short laser pulses

    Författare :Mikael Kjellberg; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Photoelectron spectroscopy; Momentum mapping imaging; thermal ionization; above threshold ionization; molecular fusion; fullerenes; polyaromatic hydrocarbons; femtosecond-laser.;

    Sammanfattning : The decay dynamics of fullerenes and polyaromatic hydrocarbons (PAH) after femtosecond-laser excitation have been studied experimentally by electron momentum mapping and mass spectrometry. The electron spectra of fullerenes and large PAH-molecules were found to be exponentially decreasing with energy without any distinct peaks outside the photon energy. LÄS MER