Search for dissertations about: "vibrational modes"

Showing result 1 - 5 of 54 swedish dissertations containing the words vibrational modes.

  1. 1. Understanding the interactions between vibrational modes and excited state relaxation in garnet structured phosphors

    University dissertation from Gothenburg : Chalmers tekniska högskola

    Author : Yuan-Chih Lin; [2018]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; thermal quenching.; luminescence; garnet; vibrational spectroscopy; neutron scattering; phosphor; light emitting diode;

    Abstract : This thesis concerns investigations of the local structural environments and vibrational dynamics of the three garnet type oxide phosphors Ce3+-doped Y3Al5O12 (YAG:Ce3+), Ca3Sc2Si3O12 (CSS:Ce3+), and Sr3Y2Ge3O12 (SYG:Ce3+), which show promising optical properties as luminescent materials used in solid state white lighting technologies. The study focuses on a comprehensive analysis of the nature of the long-range vibrations (phonons) in terms of local atomic and molecular motions of the garnet structure, as well as their dependence on the nature of the garnet chemical composition, Ce3+ concentration and temperature. READ MORE

  2. 2. Structure-Specific Vibrational Modes of Isolated Biomolecules Studied with Mid- and Far-Infrared Laser Spectroscopy

    University dissertation from Gothenburg : Department of Physics, University of Gothenburg

    Author : Vasyl Yatsyna; Göteborgs universitet.; Gothenburg University.; [2019]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; far-infrared gas-phase spectroscopy; conformers; vibrational anharmonicity; infrared multiple photon dissociation; peptide structure; folded and extended peptides; hydrogen bonding;

    Abstract : Biomolecular structure elucidation is crucial for our detailed understanding of various biological processes, since there is an intimate relationship between the biomolecular function and structure. In this respect, isolated biomolecules, despite being outside of their natural environment, are perfect model systems for in-depth studies of various fundamental interactions that govern the formation of biomolecular structure. READ MORE

  3. 3. Surface Vibrational and Electron Spectroscopy - Experiments and first-principle calculations

    University dissertation from Martin Andersson, Östervång 30, 247 32 Södra Sandby, Sweden

    Author : Martin Andersson; Lund University.; Lunds universitet.; [2004]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; gränsskikt; anharmonicity; Ytkemi; Surface and boundary layery chemistry; adsorbates; metal surface; density functional theory; first-principle calculations; electron spectroscopy; reflection-absorption infrared spectroscopy; vibrational spectroscpy;

    Abstract : This work deals with interpretation of experimental surface spectroscopic data with the aid of first-principle calculations. Surface infrared reflection-absorption spectra as well as spectra from the electron spectroscopic methods photoemission and X-ray absorption are considered. READ MORE

  4. 4. Vibrational Spectroscopy of Surface Adsorbates on Metal Surfaces. Experiments and Calculations

    University dissertation from Ragnar K. Ásmundsson, Chemical Physics, Lund University

    Author : Ragnar K Ásmundsson; Lund University.; Lunds universitet.; [1999]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ab initio electronic structure calculations; Fermi resonance; vibrational spectroscopy; Reflection absorption infrared spectroscopy; Fourier transform infrared spectroscopy; Cu 100 and W 110 single crystal surfaces; Physics; Fysik;

    Abstract : This work deals with a detailed analysis of the vibrational spectra of methoxy (CH3O-) and ethoxy (CH3CH2O-) on W(110) and Cu(100) single crystal surfaces. By using theoretical ab initio quantum mechanical modeling, it is demonstrated that an unprecedented quantitative understanding of the vibrational frequencies of a surface adsorbate can be obtained. READ MORE

  5. 5. ZnO Quantum Dots : Size Dependent Optical, Vibrational and Photoelectrochemical Properties

    University dissertation from T.J Jacobsson production

    Author : Jesper Jacobsson; Uppsala universitet.; [2012]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ZnO; nanoparticels; quantum dots; Chemistry with specialization in Inorganic Chemistry; Kemi med inriktning mot oorganisk kemi;

    Abstract : This thesis is devoted to quantum dots of ZnO in the size regime 2.5-10 nm.The focus is directed towards their size dependent properties with specialemphasis on the optical, vibrational and photocatalytic properties. The particleswere synthesized by hydrolysis in alkaline zinc acetate solution. READ MORE