Sökning: "electron paramagnetic resonance"

Visar resultat 21 - 25 av 52 avhandlingar innehållade orden electron paramagnetic resonance.

1. 21. Density functional studies of EPR and NMR parameters of paramagnetic systems

   Författare :Lyudmyla G. Telyatnyk; Olav Vahtras; Martin Kaupp; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spin-restricted DFT; restricted-unrestricted approach; EPR spin Hamiltonian parameters; NMR spin Hamiltonian parameters; Bioorganic chemistry; Bioorganisk kemi;

   Sammanfattning : Experimental methods based on the magnetic resonance phenomenon belong to the most widely used experimental techniques for investigations of molecular and electronic structure. The difficulty with such experiments, usually a proper interpretation of data obtained from high-resolution spectra, opens new challenges for pure theoretical methods. LÄS MER

3. 22. Magnetic Resonance Parameters of Radicals Studied by Density Functional Theory Methods

   Författare :Lyudmyla Telyatnyk; KTH; []
   Nyckelord :electronic g-tensor; hyperfine coupling constant; nuclear shielding tensor; spin restricted DFT; restricted-unrestricted appoach;

   Sammanfattning : The recent state of art in the magnetic resonance area putsforward the electron paramagnetic resonance, EPR, and nuclearmagnetic resonance, NMR, experiments on prominent positions forinvestigations of molecular and electronic structure. A mostdifficult aspect of such experiments is usually the properinterpretation of data obtained from high-resolution spectra,that, however, at the same time opens a great challenge forpure theoretical methods to interpret the spectral features. LÄS MER

4. 23. Trapping Tyrosine Z : Exploring the Relay between Photochemistry and Water Oxidation in Photosystem II

   Författare :Johannes Sjöholm; Stenbjörn Styring; Fikret Mamedov; A. William Rutherford; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Photosystem II; Tyrosine Z; EPR; proton-coupled electron transfer; hydrogen bond; pH;

   Sammanfattning : Photosystem II is unique! It remains the only enzyme that can oxidize water using light as energy input. Water oxidation in photosystem II is catalyzed by the CaMn4 cluster. The electrons extracted from the CaMn4 cluster are transferred to P680+ via the tyrosine residue D1-Tyr161 (YZ). LÄS MER

5. 24. Water Relaxation Processes as Seen by NMR Spectroscopy Using MD and BD Simulations

   Författare :Ken Åman; Per-Olof Westlund; Arnold Maliniak; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; NMR; Stochastic Liouville Equation; Brownian Dynamics; Molecular Dynamics; Water; Relaxation; Deuterium; ESR; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi; Physical Chemistry; fysikalisk kemi;

   Sammanfattning : This thesis describes water proton and deuterium relaxation processes, as seen by Nuclear Magnetic Resonance (NMR) spectroscopy, using Brownian Dynamics (BD) or Molecular Dynamics (MD) simulations. The MD simulations reveal new detailed information about the dynamics and order of water molecules outside of a lipid bilayer. LÄS MER

7. 25. Fabrication of Low-Dimensional Structures in III-V Semiconductors

   Författare :Ivan Maximov; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; III-V semiconductors; plasma; etching; aerosol; lithography; quantum dots; quantum well wires; quantum point contact; damage; luminescence; Fysicumarkivet A:1997:Maximov; Halvledarfysik; Semiconductory physics;

   Sammanfattning : The thesis presents studies on the processing technology and the characterization of nanometer-sized and low-dimensional structures in III-V semiconductors. Two major approaches are described: 1) the combination of aerosol technology and plasma etching for the fabrication of quantum dots (QDs) in InP-based materials and 2) the use of high-resolution electron beam lithography and plasma or wet chemical etching to make quantum well wires (QWWs) in both GaAs and InP-based structures. LÄS MER