Sökning: "H-bond"

Visar resultat 16 - 20 av 37 avhandlingar innehållade ordet H-bond.

1. 16. Thiyl radicals, reaction kinetics and redox chemistry

   Författare :Rong Zhao; KTH; []
   Nyckelord :;

   Sammanfattning : In focusing on the free radical chemistry of thiyl radicals,two importantclasses are dealt with, namely, the amino acidalkylthiyl and the acylthiyl radicals, where pulse radiolysisand steady state γ-radiolysis are applied.Amino acid thiyl radicals (RS•), are important in manybiological systems,as intermediates in the repair reactions ofthiols towards targeted carbon-centeredradicals and ascatalytic centers in many enzymatic reactions. LÄS MER

3. 17. Simulation of Core-Level Spectra of H-bonded Systems

   Författare :Iurii Zhovtobriukh; Lars G.M. Pettersson; Anders Nilsson; Marcus Lundberg; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; water; x-ray absorption; non-resonant x-ray emission; damped linear response theory; time-dependent density functional theory; semi-classical approximation to Kramers-Heisenberg formula; Reverse Monte-Carlo; kemisk fysik; Chemical Physics;

   Sammanfattning : The thesis consists of three related projects where attempts have been made to simulate X-Ray Absorption (XAS) spectra of water and hexagonal ice, static non-resonant X-ray Emission (XES) spectrum of water and to apply the semi-classical approximation to Kramers-Heisenberg formula (SCKH) formalism to calculate the non-resonant XES spectrum of water and methanol. The first project is devoted to an investigation of the performance of damped response theory in combination with the DFT electronic structure method (CPP-DFT) in XAS spectrum simulations of liquid water. LÄS MER

4. 18. 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. 19. Advances in Stereoselective Palladium(ΙΙ)-Catalyzed Oxidative Transformations of Allenes

   Författare :Daniels Posevins; Jan-Erling Bäckvall; Troels Skrydstrup; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Synthesis; Palladium Catalysis; Allenes; Biomimetic; Carbocyclization; Borylation; Carbonylation; Oxidation; Heterogeneous; organisk kemi; Organic Chemistry;

   Sammanfattning : Palladium(ΙΙ)-catalyzed carbon-carbon and carbon-heteroatom bond formation via selective C-H bond oxidation constitutes a step-economical and versatile approach towards complex target molecules. This thesis has been focused on the development of new selective palladium(ΙΙ)-catalyzed transformations of allenes under oxidative conditions catalyzed by either homogenous or heterogeneous palladium(ΙΙ) catalysts. LÄS MER

7. 20. Structure, Bonding and Chemistry of Water and Hydroxyl on Transition Metal Surfaces

   Författare :Klas Andersson; Anders Nilsson; Falko Netzer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; core-level spectroscopy; surface chemistry; water; hydroxyl; metal surfaces; adsorption; structure; hydrogen bonding; Chemical physics; Kemisk fysik;

   Sammanfattning : The structure, bonding and chemistry of water and hydroxyl on metal surfaces are presented. Synchrotron based x-ray photoelectron- and x-ray absorption spectroscopy along with density functional theory calculations mainly form the basis of the results. LÄS MER