Search for dissertations about: "Kvantkemi"

Showing result 6 - 10 of 63 swedish dissertations containing the word Kvantkemi.

  2. 6. Global bifurcations and chaotic dynamics in physical applications

    Author : Martín G. Zimmermann; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Global bifurcations; Šil´nikov phenomenon; degenerate homoclinic orbit; onset of spatiotemporal chaos; heteroclinic cycles; orientation- and inclination-flip bifurcations; Kvantkemi; Quantum chemistry; Kvantkemi; Quantum Chemistry; kvantkemi;

    Abstract : The aim of this work has been to analyse global bifurcations arising in a laser with injectedsignal and in a catalytic reaction on a surface of Pt, from the point of view of dynamicalsystems theory.The 3-dimensional ordinary differential equation which models the laser was found to contain a homoclinic orbit to a saddle-focus equilibrium, what corresponds to the Šil´nikov phenomenon. READ MORE

  4. 7. Theoretical Photochemistry : Halogenated Arenes, Phytochromobilin, Ru(II)polypyridyl complexes and 6-4 photoadducts

    Author : Anders Borg; Sten Lunell; Hans Karlsson; Luis Serrano-Andrés; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Quantum Chemistry; Halogenated Arenes; Phytochromobilin; Phytochrome; Ruthenium; 6-4 photoadducts; Photochemistry; Kvantkemi; Quantum chemistry; Kvantkemi;

    Abstract : This thesis presents Quantum Chemical calculations on the Photochemistry of Halogenated benzenes, Phytochromobilin, Ruthenium Polypyridyl complexes and 6-4 photoadducts in DNA. The work is focused on improving the understanding of a number of experimentally observed photochemical processes in these systems. READ MORE

  5. 8. Quantum Chemical Studies of Protein-Bound Chromophores, UV-Light Induced DNA Damages, and Lignin Formation

    Author : Bo Durbeej; Leif Eriksson; Tim Clark; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; quantum chemistry; calculations; density functional theory; excited states; photochemistry; chromophores; absorption spectra; bathochromic shift; isomerization; UV radiation; DNA damages; cycloaddition reactions; photoenzymic repair; electron transfer; lignin; polymerization; phenoxy radicals; dilignols; Kvantkemi; Quantum chemistry; Kvantkemi;

    Abstract : Quantum chemical methods have been used to provide a better understanding of the photochemistry of astaxanthin and phytochromobilin; the photoenzymic repair of UV-light induced DNA damages; and the formation of lignin. The carotenoid astaxanthin (AXT) is responsible for the colouration of lobster shell. READ MORE

  6. 9. Quantum Chemical Modeling of Dye-Sensitized Titanium Dioxide : Ruthenium Polypyridyl and Perylene Dyes, TiO2 Nanoparticles, and Their Interfaces

    Author : Maria J. Lundqvist; Sten Lunell; Petter Persson; Lars Ojamäe; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; density functional theory; chromophore; nanocrystal; interface; photoexcitation; triplet state; surface electron transfer; electronic coupling strength; Kvantkemi; Quantum chemistry; Kvantkemi;

    Abstract : Quantum chemical calculations have been used to model dye-sensitized nanostructured titanium dioxide systems that can be used in solar cells for solar energy to electricity conversion. Structural, electronic and spectral properties of isolated dyes and both bare and dye-sensitized TiO2 have been calculated with density functional theory, providing detailed information about both the separate parts and the dye-TiO2 interface. READ MORE

  7. 10. Computational Investigation of Dye-Sensitized Solar Cells

    Author : Mattias Nilsing; Sten Lunell; Lars Ojamäe; Petter Persson; Sven Stafström; Uppsala universitet; []
    Keywords : Quantum chemistry; titanium dioxide; anatase; rutile; pyridine; perylene; nanostructured; interface; electronic coupling; electron injection; quantum chemistry; phosphonic acid; Kvantkemi;

    Abstract : Interfaces between semiconductors and adsorbed molecules form a central area of research in surface science, occurring in many different contexts. One such application is the so-called Dye-Sensitized Solar Cell (DSSC) where the nanostructured dye-semiconductor interface is of special interest, as this is where the most important ultrafast electron transfer process takes place. READ MORE