Search for dissertations about: "excitons"

Showing result 11 - 15 of 67 swedish dissertations containing the word excitons.

  2. 11. 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

  4. 12. Complex Excitations in Advanced Functional Materials

    Author : Johann Lüder; Barbara Brena; Frank de Groot; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; X-ray Absorption Spectroscopy; Photoelectron Spectroscopy; Adsorption; Phthalocyanines; Biphenylene; Excitons; Functional Materials;

    Abstract : Understanding the fundamental electronic properties of materials is a key step to develop innovations in many fields of technology. For example, this has allowed to design molecular based devices like organic field effect transistors, organic solar cells and molecular switches. READ MORE

  5. 13. 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. 14. Excitons in a high magnetic field

    Author : Alexandre V. Petrov; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; fysik; Physics;

    Abstract : The interaction of excitons with each other and with charged impurities has been studied in a high magnetic field when the distance between the Landau levels is greater than the Coulomb unit of energy, in the frame of the model suitable for description of Wannier excitons in semiconductors. The analytical expressions for the pair interaction potential between hydrogenlike excitons in a high magnetic field are derived for the triplet and singlet terms. READ MORE

  7. 15. Out of the Dark and into the Light - Microscopic Analysis of Bright, Dark and Trapped Excitons

    Author : Maja Feierabend; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; density matrix formalism; localized states; impurities; dark excitons; strain; transition metal dichalcogenides; Bloch equations;

    Abstract : Atomically thin transition metal dichalcogenides (TMDs) have been in the focus of current research due to their efficient light-matter interaction, as well as the remarkably strong Coulomb interaction that leads to tightly bound excitons. Due to their unique band structure, TMDs show a variety of optically accessible bright and inaccessible dark excitons. READ MORE