Search for dissertations about: "vibrational relaxation"

Showing result 1 - 5 of 29 swedish dissertations containing the words vibrational relaxation.

2. 1. Relaxation and Resonance in Brownian Motion-Coupled Resonators

   Author : Christin Rhen; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; nonequilibrium dynamics; nonlinear dynamics; resonance; nanomechanics; relaxation; superconducting circuits.; resonator; dispersive coupling; noise; Brownian motion;

   Abstract : In physics, there exists a number of paradigm systems – exactly solvable models that can represent a wide variety of physical realizations. My research is concerned with two of these paradigm systems: the harmonic oscillator and Brownian motion. READ MORE

4. 2. Electronic and Vibrational Coherence in Photosynthetic and Model Systems

   Author : Mirianas Chachisvilis; Kemisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Kemi; Chemistry; Ultrafast relaxation; Porphyrins; Delocalization; Anisotropy; Wavepacket; Vibrational Coherence; Excitons; Electronic coherence; Energy transfer; Femtosecond spectroscopy; Photosynthesis;

   Abstract : Ultrafast optical response and excitation energy dynamics in light harvesting pigment-protein complexes and in a few model systems have been studied both experimentally and theoretically. Femtosecond light pulses were employed to excite the system and monitor the subsequent time evolution of the transient absorption kinetics and anisotropy. READ MORE

5. 3. Formation and Dynamics of Molecular Excitons and their Fingerprints in Nonlinear Optical Spectroscopy

   Author : Pär Kjellberg; Kemisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; supraledare; magnetisk resonans; spektroskopi; Physical chemistry; Fysikalisk kemi; Photochemistry; Fotokemi; Kondenserade materiens egenskaper:elektronstruktur; magnetiska och optiska ; egenskaper elektriska; supraconductors; magnetic resonance; relaxation; spectroscopy; Fysik; Chemistry; Kemi; Condensed matter:electronic structure; electrical; Physics; Redfield relaxation theory ; Inhomogeneous broadening ; Time-dependent density functional theory ; Conjugated polymers ; Three-pulse photon echo ; Molecular excitons ; magnetic and optical properties; Nonlinear spectroscopy ;

   Abstract : An efficient transfer of energy in molecular systems has proven to be of fundamental importance both in nature and industrial applications. The ability of molecules to work together forming collective excitations, so-called excitons, plays a key role in for example the extraordinary fast energy transfer involved in the first steps of photosynthesis. READ MORE

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

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

   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

7. 5. Gas phase molecular relaxation probed by synchrotron radiation experiments

   Author : Jaume Rius i Riu; KTH; []
   Keywords : Molecular relaxation; synchrotron radiation; dispersed fluorescence; photoelectron spectroscopy; energy resolved electron ion coincidence technique;

   Abstract : This thesis presents experimental studies of gas phasemolecular relaxation after excitation with synchrotron photonsin the 15-35 eV and in the 70-350 eV regions.In the 15-35 eV region, molecular relaxation by neutraldissociation processes and nonFranck-Condon effects in N2 and O2 molecules have beenstudied by means of dispersed fluorescence and photoelectronspectroscopy experimental techniques, respectively. READ MORE