Search for dissertations about: "vibrational frequencies"
Showing result 1 - 5 of 45 swedish dissertations containing the words vibrational frequencies.
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1. Surface Vibrational and Electron Spectroscopy - Experiments and first-principle calculations
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
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2. Physisorption of CO and N2O on ceria surfaces
Abstract : Physisorption of CO and N2O on surfaces of ceria (CeO2) was investigated by means of high-level quantum-mechanical embedded cluster calculations. Both systems have high relevance in the field of environmental chemistry and heterogeneous catalysis. READ MORE
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3. Vibrational Spectroscopy of Surface Adsorbates on Metal Surfaces. Experiments and Calculations
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
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4. Vibrational and Structural Characterisation in Two Perovskite Challenges: A Density Functional Theory Study
Abstract : The modelling of perovskites using density functional theory (DFT) can sometimes be a challenge with many different states very close in energy. In particular, the tilting of the inscribed octahedron, as well as the formation of electron polarons, leads to states with energy differences in the meV range. READ MORE
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5. Understanding the interactions between vibrational modes and excited state relaxation in garnet structured phosphors
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