Sökning: "Raman shifting"

Hittade 4 avhandlingar innehållade orden Raman shifting.

  1. 1. Laser induced effects in carbon nanotubes : implications for Raman characterization of functionalized systems

    Författare :David Olevik; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Fysik;

    Sammanfattning : Carbon nanotubes (CNTs) have attracted attention over the past decade because of their outstanding mechanical and electronic properties. These tiny tubular shells made of carbon atoms can be metallic or semiconducting and while having diameters of only about one nanometer (10-9 m), they can be up to centimeters in length, making them quasi one-dimensional (molecular wires). LÄS MER

  3. 2. Time Resolved Laser Spectroscopy of Rydberg States in Group IIIA and IIIA Elements

    Författare :Göran Jönsson; Fysiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In this work radiative properties of neutral elements with one or two electrons outside closed subshells have been investigated. Using laser techniques in connection with atomic beams selective excitation of Rydberg states was performed. Most of the studied states were populated with two-step excitation. LÄS MER

  4. 3. Time-resolved laser spectroscopic studies of atoms, ions and Molecules

    Författare :Zhongshan Li; Fysiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; Atom- och molekylärfysik; Fysicumarkivet A:2000:Li;

    Sammanfattning : Time-resolved laser spectroscopy has been performed to study the radiative properties of various microscopic systems. Using Laser-Induced Fluorescence (LIF) techniques, natural radiative lifetimes have been studied not only in neutral B, S, Ge, Ce, Pb, and in singly ionized V, Fe, Zr, Mo, La, Ce, Eu, Gd and Yb, but also in doubly ionized La, Ce, Pr, Eu, Er, Gd, Tm, Lu, and W. LÄS MER

  5. 4. 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