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Visar resultat 1 - 5 av 257 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Ultrafast Photo-induced Reaction Dynamics of Small Molecules

    Författare :Malin Kadi; Jan Davidsson; Eva Åkesson; Sören Keiding; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; pump-probe spectroscopy; reaction dynamics; photodissociation; aryl halides; spin-orbit coupling; ab initio calculations; molecular dynamics; vibrational wavepackets; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : The main focus of this thesis is the investigation of the dissociation dynamics of aryl halides using femtosecond pump-probe spectroscopy. In the monohalogenated aryl halides, iodo-, bromo- and chlorobenzene, the rate of dissociation following excitation at 266 nm in the gas phase increased with increasing mass of the halogen atom. LÄS MER

  3. 2. Reaction dynamics on highly excited states

    Författare :Johanna Brinne Roos; Åsa Larson; Ioan F. Schneider; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio calculations; dissociative recombination; resonant ion-pair formation; mutual neutralization; molecular electronic states; molecule-electron collisions; quantum chemistry; molecular dynamics; Chemical physics; Kemisk fysik; Molecular physics; Molekylfysik; kemisk fysik; Chemical Physics;

    Sammanfattning : In this thesis I have performed theoretical studies on the reaction dynamics in few-atom molecules. In particular, I have looked at reaction processes in which highly excited resonant states are involved. LÄS MER

  4. 3. Freshwater, density gradients and biological processes in cold, brackish seas : aspects of the biogeophysical fluid dynamics characterising the Baltic Sea

    Författare :Tapani Stipa; Peter Haugan; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Östersjön; Oceanografi; meteorologi; Meteorology;

    Sammanfattning : The dominant component in the ocean water is freshwater. In this thesis its mixing and the freshwater-induced dynamics are discussed, with cold, brackish basins such as the Baltic Sea especially in mind. A mathematical framework is derived to allow for a consistent way of adding freshwater effects to the governing equations. LÄS MER

  5. 4. X-ray free-electron laser based methods for structural and ultrafast dynamics studies of a photosynthetic reaction centre

    Författare :David Arnlund; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; WAXS; wide-angle x-ray scattering; XFEL; x-ray free-electron laser; reaction center; structural biology; ultrafast dynamics;

    Sammanfattning : Life on earth is fuelled by the energy of sunlight, which must first be captured and converted into a chemical energy form useful to the cell. This process is known as photosynthesis and the major pathway of this energy conversion is via photosynthetic reaction centres. LÄS MER

  7. 5. Ultrafast dynamics of small quantum systems studied using electron-ion coincidence spectroscopy

    Författare :Smita Ganguly; Synkrotronljusfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; coincidence spectroscopy; photodissociation dynamics; fragmentation reaction; MOLECULAR-BEAM; Cluster fission; Astrochemistry; Carbon dioxide CO2 ; ; Adamantane;

    Sammanfattning : Studying how small quantum systems, like molecules and clusters, interact with X-rays is crucial to understanding the ultrafast processes that occur in nature on incredibly short timescales, ranging from femtoseconds to picoseconds. X-rays excite small quantum systems to unstable core hole states, leading to a cascade of phenomena, including Auger decay, nuclear rearrangement, and dissociation. LÄS MER