Search for dissertations about: "Ultrafast relaxation"

Showing result 1 - 5 of 25 swedish dissertations containing the words Ultrafast relaxation.

2. 1. Studies of Ultrafast Relaxation and Photodissociation Processes in Solution

   Author : Peter Salén; Peter van der Meulen; Jan Davidsson; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; ultrafast spectroscopy; liquid phase; Physics; Fysik;

   Abstract : This thesis focuses on femtosecond studies of relaxation and photo-induced dissociation processes in the liquid environment. Measurements are performed using both polarization sensitive and magic angle transient absorption spectroscopy with excitation wavelengths of 387 nm and 258 nm and a white light continuum probe. READ MORE

4. 2. Ultrafast, Non-Equilibrium Electron Transfer Reactions of Molecular Complexes in Solution

   Author : Jonas Petersson; Leif Hammarström; Antonín Vlček; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; electron transfer; laser; spectroscopy; transient absorption; anisortopy; inter ligand electron transfer; dye sensitized solar cell; DSSC; vibrational relaxation; ultrafast dynamics; fs spectroscopy; Kemi med inriktning mot kemisk fysik; Chemistry with specialization in Chemical Physics;

   Abstract : Photoinduced electron transfer is a fundamentally interesting process; it occurs everywhere in the natural world. Studies on electron transfer shed light on questions about the interaction between molecules and how the dynamics of these can be utilized to steer the electron transfer processes to achieve a desired goal. READ MORE

5. 3. Time-Resolved Photoemission Electron Microscopy: Development and Applications

   Author : Lukas Wittenbecher; NanoLund: Centre for Nanoscience; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; PEEM; time-resolved PEEM; ultrafast optics; pulse shaping; plasmonics; semiconductor nanowires; hot electrons; ultrafast microscopy; charge carrier relaxation;

   Abstract : Time-resolved photoemission electron microscopy (TR-PEEM) belongs to a class of experimental techniquescombining the spatial resolution of electron-based microscopy with the time resolution of ultrafast opticalspectroscopy. This combination provides insight into fundamental processes on the nanometer spatial andfemto/picosecond time scale, such as charge carrier transport in semiconductors or collective excitations ofconduction band electrons at metal surfaces. READ MORE

6. 4. Ultrafast spin dynamics and relaxation in metallic ferromagnets

   Author : Vivek Unikandanunni; Stefano Bonetti; Olof Karis; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetization dynamics; Three temperature model; Cobalt; Anisotropy; Electron-phonon coupling; THz; Platinum; Silver; fysik; Physics;

   Abstract : We performed ultrafast demagnetization measurements on epitaxial hcp-cobalt thin film with the easy axis in the plane of the film by pumping the sample with 400 nm radiation and probing the magneto-optic effects in the longitudinal magneto optic Kerr effect geometry using 800 nm radiation. The in-plane magnetic anisotropy of the sample enabled us to measure the demagnetization dynamics along two different crystalline directions, namely along the easy axis and at 45 degrees between the easy and hard axes. READ MORE

7. 5. An X-ray Based Spectroscopic Study of Structure Influencing Electrons : Fragmentation, Ultrafast Charge Dynamics and Surface Composition

   Author : Geethanjali Gopakumar; Olle Björneholm; Carl Caleman; Isaak Unger; Ruth Signorell; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fragmentation; ICD; ETMD; Ultrafast electron dynamics; Surface propensity;

   Abstract : The structure of biomolecules, such as proteins, is intimately connected to the function of the molecules. These structures are often studied using X-ray diffraction. However, the interaction of the X-ray photons with the molecule can excite or ionize its electrons which in turn can causes changes in the molecular structure. READ MORE