Sökning: "X-ray Absorption Spectroscopy"

Visar resultat 11 - 15 av 218 avhandlingar innehållade orden X-ray Absorption Spectroscopy.

1. 11. Multimode resonant X-ray scattering of free molecules

   Författare :Nina Ignatova; Victor Kimberg; Faris Gel’mukhanov; Sergey Polyutov; Hans Ågren; Piero Decleva; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; core-excited state; nuclear dynamic; wave-packet; resonant inelastic X-ray scattering; Franck-Condon; water; methanol; water isotopomer; pump-probe; quantum chemistry; ultrafast dissociation; Kemi; Chemistry; Fysik; Physics;

   Sammanfattning : This thesis is focused on the role that nuclear dynamics plays in the formation of X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectra of multimode free molecules. A combined approach based on ab initio electronic structure methods and quantum nuclear wave packet dynamics is applied to two systems -- water and methanol in the gas phase. LÄS MER

3. 12. Modeling hybrid halide perovskites for solar cell applications : Simulations of electronic structure and X-ray spectroscopy

   Författare :Cody M. Sterling; Michael Odelius; Alison B. Walker; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; perovskites; computational chemistry; simulations; electronic structure; density functional theory; X-ray spectroscopy; kemisk fysik; Chemical Physics;

   Sammanfattning : Over the past 13 years, perovskites have become a very promising candidate in the search for cheap and effective photovoltaic materials for solar cells.  Perovskite solar cell power conversion efficiency has increased from 3. LÄS MER

4. 13. Structure Modeling with X-ray Absorption and Reverse Monte Carlo: Applications to Water

   Författare :Mikael Leetmaa; Lars G M Pettersson; John Rehr; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water structure; x-ray absorption; spectroscopy; diffraction; reverse monte carlo; XAS; EXAFS; XANES; RMC; TP-DFT spectrum calculations; Physics; Fysik; kemisk fysik; Chemical Physics;

   Sammanfattning : Water is an important substance. It is part of us, of our environment, and is a fundamental prerequisite for the existence of life as we know it. The structure of water is still, after over 100 years of research on the subject, however under debate. LÄS MER

5. 14. Structural studies of ba3-type cytochrome c oxidase using serial crystallography and X-ray absorption spectroscopy

   Författare :Doris Zoric; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ba3-type cytochrome c oxidase; structural biology; X-rays; serial X-ray crystallography; X-ray absorption spectroscopy; enzyme reaction dynamics;

   Sammanfattning : Cytochrome c oxidase (CcO) catalyses the reduction of molecular oxygen to water while the energy released in this process is used transport protons “up-hill” across an energy transducing biological membrane, creating a proton-motive force for ATP synthesis. Given its key role in energy transduction in organisms, proton pumping has been extensively studied across species. LÄS MER

7. 15. Infrared - X-ray pump probe spectroscopy

   Författare :Viviane Costa Felicissimo; Faris Gelmukhanov; KTH; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Biochemistry; Biokemi; Biochemistry; Biokemi;

   Sammanfattning : The present thesis concerns theoretical studies of molecular interactions investigated by infrared and X-ray spectroscopic techniques, with emphasis on using the two technologies combined in pump probe experiments. Three main types of studies are addressed: the use of near-edge X-ray absorption fine structure spectra (NEXAFS) to manifest through-bond and through-space interactions; the role of hydrogen bonding on the formation of X-ray photoelectron spectra as evidenced by simulations of the water dimer; and the development of theory, with sample applications, for infrared X-ray pump probe spectroscopy - the main theme of the thesis. LÄS MER