Sökning: "Ultrafast relaxation"

Visar resultat 21 - 25 av 25 avhandlingar innehållade orden Ultrafast relaxation.

1. 21. Charge Separation on Localized Surface Plasmon and Hot Carrier Transfer to Semiconductors

   Författare :Yocefu Hattori; Jacinto Sá; Stephan Link; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plasmonics; hot carrier; metal nanoparticles; semiconductors; ultrafast transient absorption spectroscopy; Chemistry with specialization in Physical Chemistry; Kemi med inriktning mot fysikalisk kemi;

   Sammanfattning : The relatively recent discovery that plasmonic nanoparticles generate energetic electron-hole pairs known as hot carriers has been the source of interest from many scientific groups. The capability to extract these short-lived hot carriers from metal nanoparticles (NPs) might potentially lead to applications in solar cells, photodetection, and photocatalysis. LÄS MER

3. 22. Spin dynamics in the terahertz regime

   Författare :Kumar Neeraj; Stefano Bonetti; Markus Kowalewski; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fysik; Physics;

   Sammanfattning : It is known that the use of conventional optical lasers for the study of ultrafast magnetization dynamics imparts heat to the materials under study, which creates a highly non equilibrium state and masks the fundamental coupling processes leading to ultrafast demagnetization. In order to understand, control and manipulate the dynamics of spins in magnetic systems a new kind of radiation called terahertz (THz) is starting to be used in recent years. LÄS MER

4. 23. Spin Dynamics and Magnetic Multilayers

   Författare :Björn Skubic; Olle Eriksson; Lars Nordström; Mark D. Stiles; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; magnetism; electronic structure; density functional theory; spin dynamics; spin-transfer torque; spin-density wave; multilayer; interface structure; Fysik;

   Sammanfattning : Theoretical studies based on first-principles theory are presented for a number of different magnetic systems. The first part of the thesis concerns spin dynamics and the second part concerns properties of magnetic multilayers. The theoretical treatment is based on electronic structure calculations performed by means of density functional theory. LÄS MER

5. 24. Life of Excitons in Artificial Photosynthetic Antennas

   Författare :Johan Andersson; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Zn-porphyrin; Osmium; Ruthenium; Polypyridine; Inter Ligand Energy Transfer; Inter System Crossing; Excited state dynamics; Transition metal complexes; Photosynthetic Antennas; Solar energy conversion; Artificial photosynthesis; Physical chemistry; Fysikalisk kemi; Transient Absorption Anisotropy.; Reaction Center; Dendrimer; Energy Transfer;

   Sammanfattning : Due to the predicted energy crisis when fossil fuels will be exhausted it is important to search for alternative energy sources. Utilizing sunlight via artificial photosynthesis is an interesting possibility. LÄS MER

7. 25. X-Ray Investigations of the Liquid-Liquid Critical Point Hypothesis in Supercooled Water

   Författare :Alexander Späh; Anders Nilsson; Martin Meedom Nielsen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water; supercooled water; x-ray scattering; free electron x-ray laser; liquid-liquid phase transition; liquid-liquid critical point; x-ray speckle visibility spectroscopy; kemisk fysik; Chemical Physics;

   Sammanfattning : This thesis presents experimental x-ray scattering studies on supercooled liquid water. A liquid-liquid transition between two structurally distinct configurations has been found in deeply supercooled water, indicating the existence of a liquid- liquid critical point. LÄS MER