Sökning: "Ultrafast probing"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Ultrafast probing.

  1. 1. Ultrafast Probing of CO Reactions on Metal Surfaces : Changes in the molecular orbitals during the catalysis process

    Författare :Jörgen Gladh; Henrik Öström; Nils Mårtensson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hetrogenous catalysis; CO; transition metals; Ultrafast probing; oxidation; desorption; dissociation; kemisk fysik; Chemical Physics;

    Sammanfattning : This thesis presents experimental studies of three different chemical reaction steps relevant for heterogeneous catalysis: dissociation, desorption, and oxidation. CO on single-crystal metal surfaces was chosen as the model systems. LÄS MER

  3. 2. Investigation of Ultrafast Molecular Dynamics via Covariance Mapping : A Tool for Intense XUV Light Sources

    Författare :Jan Lahl; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Covariance; Ultrafast; High-order harmonic generation; Extreme Ultraviolet; Pump probe; FLASH; Velocity map imaging; wavefront; FEL; photodissociation; Coulomb explosion; Fysicumarkivet A:2019:Lahl;

    Sammanfattning : The study of molecular dynamics involves observations of the motion of nuclei and electrons. While nuclear motion is usually on the picosecond or femtosecond timescale, attosecond precision is necessary to directly observe the motion of electrons. LÄS MER

  4. 3. Probing Electron Collisions in Nanostructures

    Författare :Fikeraddis Damtie; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; electron-electron interaction; Time dependent dynamics; Multiple Exciton Generation; Two dimensional spectroscopy; Fysicumarkivet A:2017:Damtie;

    Sammanfattning : This thesis studies the role of interaction between charged particles for transport and optical properties in nanostructures. Simulations are provided for a quantitative description of the system dynamics probed by either current spectroscopy or light absorption. LÄS MER

  5. 4. Towards Single Molecule Imaging - Understanding Structural Transitions Using Ultrafast X-ray Sources and Computer Simulations

    Författare :Carl Caleman; Janos Hajdu; Richard Neutze; Uppsala universitet; []
    Nyckelord :Molecular biophysics; XFEL; Ultrafast Melting; InSb; Molecular Dynamics; Water Cluster; Evaporation; Secondary Electron; Photo-cathode; Electron Scattering; Energy Loss Function; Single Particle Imaging; X-ray Diffraction; Water; Ice; KI; CsI; Molekylär biofysik;

    Sammanfattning : X-ray lasers bring us into a new world in photon science by delivering extraordinarily intense beams of x-rays in very short bursts that can be more than ten billion times brighter than pulses from other x-ray sources. These lasers find applications in sciences ranging from astrophysics to structural biology, and could allow us to obtain images of single macromolecules when these are injected into the x-ray beam. LÄS MER

  7. 5. Creating and Probing Extreme States of Materials : From Gases and Clusters to Biosamples and Solids

    Författare :Bianca Iwan; Nicusor Timneanu; Janos Hajdu; Stacey Sorensen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; free-electron laser; ultrashort X-rays; non-equilibrium plasma; Coulomb explosion; isotope effect; hydrodynamic expansion; ion acceleration; high intensity lasers; ablation; time-of-flight spectroscopy; Fysik; Physics;

    Sammanfattning : Free-electron lasers provide high intensity pulses with femtosecond duration and are ideal tools in the investigation of ultrafast processes in materials. Illumination of any material with such pulses creates extreme conditions that drive the sample far from equilibrium and rapidly convert it into high temperature plasma. LÄS MER