Sökning: "X-ray Absorption Spectroscopy XAS"

Visar resultat 1 - 5 av 51 avhandlingar innehållade orden X-ray Absorption Spectroscopy XAS.

1. 1. X-ray spectroscopy on diatomic and cationic molecules

   Författare :Ludvig Kjellsson; Jan-Erik Rubensson; Marcus Agåker; Monica Turcato; Michael Meyer; John Bozek; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; resonant inelastic X-ray scattering; cationic molecule; dinitrogen; dioxygen; carbon monoxide; aqueous hydroxyl radical; lifetime-vibrational interference; RIXS; XAS; LVI; N2; O2; CO; H2O; OH;

   Sammanfattning : X-ray spectroscopy have been used to study the electronic structure of diatomic and cationic molecules. X-ray absorption spectra of the molecular cations N2+, O2+, and CO+ have been measured. LÄS MER

3. 2. 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

4. 3. Anion redox processes in novel battery cathode materials investigated by soft X-ray spectroscopy

   Författare :Felix Massel; Laurent Duda; Håkan Rensmo; Maria Hahlin; Kevin Smith; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; soft X-ray spectroscopy; X-ray absorption spectroscopy XAS ; resonant inelastic X-ray scattering RIXS ; lithium-ion battery LIB ; sodium-ion battery SIB ; anionic redox; cathode materials; layered manganese oxide; spinel LNMO;

   Sammanfattning : This thesis presents experimental investigations of the electronic structure of emerging and novel cathode materials used in lithium- and sodium-ion batteries. The investigated materials include a range of oxide materials containing the elements nickel and manganese. LÄS MER

5. 4. 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

7. 5. Operando X-ray Absorption Spectroscopy Studies of Methane Oxidation Catalysts

   Författare :Johan Nilsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; operando spectroscopy; XAS; palladium; heterogeneous catalysis; methane oxidation; XAFS;

   Sammanfattning : Operando spectroscopy is an experimental method in catalysis that combines measurements of catalytic activity and selectivity with simultaneous in situ spectroscopic characterization of the catalyst. Since the structure and composition of the catalyst are probed under reaction conditions, the method can provide valuable information to elucidate the mechanism of the studied reaction. LÄS MER