Sökning: "excited state absorption"

Visar resultat 1 - 5 av 104 avhandlingar innehållade orden excited state absorption.

1. 1. Ground and Excited State Aromaticity : Design Tools for π-Conjugated Functional Molecules and Materials

   Författare :Christian Dahlstrand; Henrik Ottosson; Miguel Solà; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fulvene; fulvalene; polyfulvene; aromaticity; triplet state; excited state; Clar structure; polybenzenoid hydrocarbons PBH ; conjugated polymers; computational chemistry; optical spectroscopy; Kemi med inriktning mot organisk kemi; Chemistry with specialization in Organic Chemistry;

   Sammanfattning : The main focus of this thesis is on the aromaticity of the ground state and electronically excited states of π-conjugated molecules and polymers, as well as how aromaticity is connected to their properties.The electronic structures of polybenzenoid hydrocarbons (PBHs) were explored through density functional theory (DFT) calculations and the π-component of the electron localization function (ELFπ). LÄS MER

3. 2. Light Control using Organometallic Chromophores

   Författare :Johan Henriksson; Patrick Norman; Olav Vahtras; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; organometallic chromophores; two-photon absorption; excited state absorption; excited state dipole moment; four-component formalism; clamping levels; spin-transition; Computational physics; Beräkningsfysik;

   Sammanfattning : The interaction between light and organometallic chromophores has been investigated theoretically in a strive for fast optical filters. The main emphasis is on two-photon absorption and excited state absorption as illustrated in the Jablonski diagram. We stress the need for relativistic calculations and have developed methods to address this issue. LÄS MER

4. 3. Excited State Processes in Solar Energy Materials

   Författare :Tomas Österman; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; Conjugated polymers; Charge transfer state; Time-resolved spectroscopy; Fluorescence; Artificial Photosynthesis; Bis-tridentate ruthenium II -complexes; Density functional theory; Quantum chemistry.;

   Sammanfattning : This dissertation covers studies of excited state processes in two types of solar energy materials: alternating polyfluorene polymers and their blends with fullerenes in the active layer of plastic solar cells, and bis-tridentate RuII-polypyridyl complexes to be used as sensitizer in systems for artificial photosynthesis. The polymer:fullerene blends were studied by transient absorption and time-resolved fluorescence measurements in order to investigate the role of the charge transfer (CT) state in charge formation. LÄS MER

5. 4. The Fate of Electronically Excited States : Ultrafast Electron and Energy Transfer in Solvated Donor-Acceptor Systems

   Författare :Staffan Wallin; Leif Hammarström; Jan Davidsson; Eric Vauthey; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; Electron transfer; Energy transfer; Anisotropy; Porphyrin; Ruthenium tris-bipyridine; Superexchange; Supramolecular; Donor-Acceptor; Charge transfer state; S2 state; Ultrafast; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

   Sammanfattning : Processes where a molecule absorbs visible light and then disposes of the excess energy via electron/energy transfer reactions have an important role both in nature (e.g. in photosynthesis) and in many technical applications (e.g. LÄS MER

7. 5. Two-Photon Excited Fluorescence Depolarisation : Experimental and Theoretical Development

   Författare :Linus Ryderfors; Emad Mukhtar; Lennart B.-Å. Johansson; Yehudi K. Levine; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-photon excitation; Fluorescence; Fluorescence depolarisation; Fluorescence anisotropy; Time-correlated single photon counting; Gold nanoparticles; Rotational diffusion; Excited state symmetry; Extended Förster theory; Orientation correlation functions; Donor-donor energy migration DDEM ; Chemical physics; Kemisk fysik;

   Sammanfattning : We have studied fundamental aspects of time-resolved two-photon excited fluorescence depolarisation. The thesis presents experimental as well as theoretical progress. LÄS MER