Sökning: "time-dependent spectroscopy"

Visar resultat 1 - 5 av 41 avhandlingar innehållade orden time-dependent spectroscopy.

1. 1. Static and time-dependent mechanical behaviour of preserved archaeological wood : Case studies of the seventeenth century warship Vasa

   Författare :Alexey Vorobyev; Kristofer Gamstedt; Eiichi Obataya; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; archaeological wood; compression test; cubic samples; elastic constants; oak wood; barrelling formation; quasi-static loading; resonant ultrasound spectroscopy RUS ; Vasa ship; creep; 3D laser scanning; Time-dependent behaviour;

   Sammanfattning : Wooden objects have been widely used in the history of humanity and play an important role in our cultural heritage. The preservation of such objects is of great importance and can be a challenging task. This thesis investigates the static and time-dependent mechanical behaviour of archaeological oak wood from the Vasa warship. LÄS MER

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

   Författare :Pär Kjellberg; Kemisk fysik; []
   Nyckelord :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 ;

   Sammanfattning : 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. LÄS MER

4. 3. Continuous-filtering Vernier spectroscopy

   Författare :Chuang Lu; Aleksandra Foltynowicz; Ove Axner; Wei Ren; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectroscopy; spectrometer; laser; optical frequency comb; optical cavity; NIR; MIR; flame; robust; time resolution; spectrum; fysik; Physics;

   Sammanfattning : Continuous-filtering Vernier spectroscopy (CF-VS) is a laser-based detection technique that combines the broad spectral coverage of an optical frequency comb (OFC) with the enhanced interaction length provided by an optical cavity. The resonances of the cavity filter the OFC to a small group of comb modes that probe the transitions of the species present in the cavity. LÄS MER

5. 4. Time-dependent molecular properties in the optical and x-ray regions

   Författare :Ulf Ekström; Patrick Norman; Knut Faegri; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; molecular physics; x-ray spectroscopy; relativity; Computational physics; Beräkningsfysik;

   Sammanfattning : Time-dependent molecular properties are important for the experimental characterization of molecular materials. We show how these properties can be calculated, for optical and x-ray frequencies, using novel quantum chemical methods. LÄS MER

7. 5. 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