Sökning: "Femtosecond spectroscopy"

Visar resultat 1 - 5 av 58 avhandlingar innehållade orden Femtosecond spectroscopy.

  1. 1. Excited States of Carotenoids and Their Functions in Light Harvesting

    Författare :Donatas Zigmantas; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; spektroskopi; magnetic and optical properties; Carotenoids; light-harvesting; excited states; excitation energy transfer; femtosecond spectroscopy; supraconductors; magnetic resonance; electrical; Condensed matter:electronic structure; time-resolved fluorescence spectroscopy; magnetisk resonans; supraledare; magnetiska och optiska ; egenskaper elektriska; Kondenserade materiens egenskaper:elektronstruktur; relaxation; spectroscopy;

    Sammanfattning : The research presented in this thesis is focused on characterization of photophysical properties of lowest singlet excited states of carotenoids and their functions in the process of photosynthetic light harvesting. It is shown that the various light-harvesting complexes utilize different strategies to achieve efficient energy transfer from carotenoids to (bacterio)chlorophylls. LÄS MER

  2. 2. Generation and metrology of ultrashort pulses and their application in attosecond science

    Författare :Lana Neoricic; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; ultrashort; filamentation; femtosecond; dispersion scan; RABBIT; photoionisation; attosecond; interferometry; pump-probe; spectroscopy; photoelectron; wavepacket;

    Sammanfattning : This thesis deals with the dynamical processes in atoms and small molecules initiated by the absorption of ultrashort, coherent light pulses. The studied phenomena takeplace on the femtosecond (1 fs = 10−15 s) and attosecond (1 as = 10−18 s) timescales and critically depend on the properties of the light fields that drive them. LÄS MER

  3. 3. Dynamics of Photoinduced Processes in Dye-Sensitized Nanocrystalline Semiconductor Films--Reactions in the Photoactive Part of the Grätzel Solar Cell

    Författare :Gabor Benko; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; supraledare; magnetisk resonans; spektroskopi; magnetiska och optiska ; egenskaper elektriska; Kondenserade materiens egenskaper:elektronstruktur; spectroscopy; relaxation; magnetic resonance; supraconductors; Kemi; Condensed matter:electronic structure; electrical; femtosecond spectroscopy; solar cells; Chemistry; excited states; photoinduced electron transfer; transition metal complexes; nanocrystalline titanium dioxide; dye sensitization; porous semiconductor film; magnetic and optical properties;

    Sammanfattning : The key materials used to convert solar energy into electricity in the Grätzel-type solar cells are dye molecules and titanium dioxide particles attached to each other. The former are similar to those in common products like purple pigments in blueberry juice, while the latter are like sunscreen, white paint, or toothpaste. LÄS MER

  4. 4. Core Level Spectroscopy of Water and Ice

    Författare :Dennis Nordlund; Anders Nilsson; Martin Wolf; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; x-ray adsorption spectroscopy; photoemission spectroscopy; x-ray photoelectron spectroscopy; platinum; x-ray emission spectroscopy; density functional theory; hydrogen-bonded; H-bond; water; ice; electronic structure; excited state dynamics; proton dynamics; water adsorption; liquid water; Physics; Fysik;

    Sammanfattning : A core level spectroscopy study of ice and water is presented in this thesis. Combining a number of experiments and spectrum calculations based on density functional theory, changes in the local valence electronic structure are shown to be sensitive to the local H-bonding configurations. LÄS MER

  5. 5. Femtosecond Dynamics and Photochemistry in Solution

    Författare :Marcus Rasmusson; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Kemi; Chemistry; cross-correlation function; chloroiodomethane; dihalides; bromobenzene; ion pairs; solvation; vibrational relaxation; charge-transfer; tetranitromethane; electron transfer; femtosecond spectroscopy; dissociation; Photochemistry; Fotokemi; Chemical technology and engineering; Kemiteknik och kemisk teknologi;

    Sammanfattning : The reaction dynamics of several polyatomic systems have been investigated in solution by femtosecond spectroscopy. Tetranitromethane-naphtalene complexes excited in the charge-transfer band at 400 nm undergo dissociative electron transfer, resulting in three primary products: [naphthalene].+, NO2 and C(NO2)3-. LÄS MER