Search for dissertations about: "electron-impact excitation"

Showing result 1 - 5 of 6 swedish dissertations containing the words electron-impact excitation.

  2. 1. Electron impact dissociation of molecular ions at CRYRING

    Author : Ahmed Al-Khalili; Ronald A Phaneuf; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; fysik;

    Abstract : In this thesis, the electron impact dissociation of molecular ions has been studied using the ion storage ring CRYRING at Manne Siegbahn Laboratory in Stockholm, Sweden. The electron impact dissociation of molecular ions occurs via many processes, which lead to different charge states of the product fragments. READ MORE

  4. 2. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra

    Author : Yeisson Fabian Martinez Osorio; Paul Barklem; Karin Lind; Nikolai Piskunov; Carlos Allende Prieto; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Spectral line: formation; atomic data; stellar abundances.; Fysik med inriktning mot astrofysik; Physics with specialization in Astrophysics;

    Abstract : 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. READ MORE

  5. 3. Electron - Ion Recombination Studies of Astrophysically Relevant Ions : Storage Ring and Electron Beam Ion Trap Based Measurements

    Author : Istvan Orban; Reinhold Schuch; Yaming Zou; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; atomic processes; electron-ion recombination; plasma; Physics; Fysik; fysik; Physics;

    Abstract : This thesis contains experimental work that was performed at two state-of-the art devices for electron-ion collision physics, at a heavy-ion storage ring and at an Electron Beam Ion Trap. As a result, absolute recombination rate coefficients for H-like Si, He-like Si, Be-like Si, and Na-like Si, as well as Be-like Ne, Na-like S and Na-like Ar are reported over a wide energy range from μeV to keV. READ MORE

  6. 4. Photodetachment of Negative Ions. Experimental Investigations of Threshold and Continuum Structures

    Author : Joakim Sandström; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; electron correlation; resonance ionization spectroscopy; doubly excited states; electron affinity; accelerator mass spectrometry; photodetachment;

    Abstract : In this thesis photodetachment studies of atomic negative ions where one or several electrons are detached from a negative ion are presented. Negative ions are unique objects since their formation and destruction mechanisms strongly depend on the correlated motion of the valence electrons. READ MORE

  7. 5. Adsorption of Molecular Hydrogen on Cu, Pd and Ni Surfaces

    Author : Krister Svensson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; electron energy loss spectroscopy; nickel; molecular chemisorption; hydrogen; palladium; physisorption; photodesorption; copper;

    Abstract : This thesis is devoted to spectroscopic studies of molecular hydrogen adsorbed on metal surfaces. Hydrogen is the simplest molecule available and is a very valuable model adsorbate. From a spectroscopic point of view there are also three easily accessible molecular isotopes, H2, HD and D2, with widely different masses. READ MORE