Sökning: "Excited state symmetry"

Visar resultat 1 - 5 av 29 avhandlingar innehållade orden Excited state symmetry.

  1. 1. Two-Photon Excited Fluorescence Depolarisation : Experimental and Theoretical Development

    Författare :Linus Ryderfors; Emad Mukhtar; Lennart B.-Å. Johansson; Yehudi K. Levine; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-photon excitation; Fluorescence; Fluorescence depolarisation; Fluorescence anisotropy; Time-correlated single photon counting; Gold nanoparticles; Rotational diffusion; Excited state symmetry; Extended Förster theory; Orientation correlation functions; Donor-donor energy migration DDEM ; Chemical physics; Kemisk fysik;

    Sammanfattning : We have studied fundamental aspects of time-resolved two-photon excited fluorescence depolarisation. The thesis presents experimental as well as theoretical progress. LÄS MER

  3. 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

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

    Författare :Yuan-Chih Lin; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; thermal quenching.; luminescence; garnet; vibrational spectroscopy; neutron scattering; phosphor; light emitting diode;

    Sammanfattning : 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. LÄS MER

  5. 4. Core Level Spectroscopy of Water and Ice

    Författare :Dennis Nordlund; Anders Nilsson; Martin Wolf; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; x-ray adsorption spectroscopy; photoemission spectroscopy; x-ray photoelectron spectroscopy; platinum; x-ray emission spectroscopy; density functional theory; hydrogen-bonded; H-bond; water; ice; electronic structure; excited state dynamics; proton dynamics; water adsorption; liquid water; Physics; Fysik;

    Sammanfattning : A core level spectroscopy study of ice and water is presented in this thesis. Combining a number of experiments and spectrum calculations based on density functional theory, changes in the local valence electronic structure are shown to be sensitive to the local H-bonding configurations. LÄS MER

  7. 5. Electromechanical Phenomena in Superconducting and Normal Nanostructures

    Författare :Milton Eduardo Peña-Aza; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; nanoelectromechanical Josephson junctions; metallic carbon nanotubes; ground-state cooling; chaos;

    Sammanfattning : This thesis summarizes a series of theoretical studies on the electromechanical properties of nanostructures made of superconducting and/or metallic elements. The first part of the work is devoted to the analysis of the interactions between the electronic and mechanical degrees of freedom in suspended nanowires. LÄS MER