Sökning: "Teoretisk kemi"

Visar resultat 1 - 5 av 444 avhandlingar innehållade orden Teoretisk kemi.

  1. 1. Theoretical Studies of Natural Gas Hydrates and H-bonded Clusters and Crystals

    Författare :Yuan Liu; Lars Ojamäe; Per-Olov Käll; Ben Slater; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES;

    Sammanfattning : In this thesis H-bonded systems (natural gas hydrates, water clusters, and crystal ice) are studied by density functional theory (DFT) computations.Natural gas hydrates (NGHs) play an important role in energy and environmental fields: NGHs are considered as a promising backup energy resource in the near-future due to their tremendous carbon content; improper exploration of NGHs could induce geological disasters and aggravate the greenhouse effect. LÄS MER

  2. 2. Computational Studies of Chemical Interactions: Molecules, Surfaces and Copper Corrosion

    Författare :Joakim Halldin Stenlid; Tore Brinck; Thomas Bligaard; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; computational chemistry; density functional theory; chemical interactions; reactivity descriptors; copper corrosion; surface and materials science; nucleophilic substitution reactions; heterogeneous catalysis; transition metal oxides; nanotechnology; beräkningskemi; täthetsfunktionalteori; kemiska interaktioner; reaktivitetsdeskriptorer; kopparkorrosion; yt- och materialvetenskap; nukleofila substitutionsreaktioner; heterogen katalys; överångsmetalloxider; nanoteknologi; Kemi; Chemistry;

    Sammanfattning : The chemical bond – a corner stone in science and a prerequisite for life – is the focus of this thesis. Fundamental and applied aspects of chemical bonding are covered including the development of new computational methods for the characterization and rationalization of chemical interactions. LÄS MER

  3. 3. Quantum Chemical Studies of Mechanisms and Stereoselectivities of Organocatalytic Reactions

    Författare :Peter Hammar; Hans Ågren; Fahmi Himo; Gregori Ujaque; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; Teoretisk kemi; Organic chemistry; Organisk kemi;

    Sammanfattning : As the field of organocatalysis is growing, it is becoming more important to understand the specific modes of action of these new organic catalysts. Quantum chemistry, in particular density functional theory, has proven very powerful in exploring reaction mechanisms as well as selectivities in organocatalytic reactions, and is the tool used in this thesis. LÄS MER

  4. 4. 5-Aminolevulinic acid and derivatives thereof : properties, lipid permeability and enzymatic reactions

    Författare :Edvin Erdtman; Leif Eriksson; Tore Brinck; Örebro universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; 5-Aminolevulinic acid; tautomerization; PDT; DFT; MM; QM MM; Porphobilinogen synthase; Uroporphyrinogen III decarboxylase; membrane penetration; enzyme mechanism; Biophysical chemistry; Biofysikalisk kemi; Quantum chemistry; Kvantkemi; Theoretical chemistry; Teoretisk kemi; Fysikalisk kemi; Physical Chemistry; Biochemistry; Biokemi;

    Sammanfattning : 5-aminolevulinic acid (5-ALA) and derivatives thereof are widely usedprodrugs in treatment of pre-malignant skin diseases of the cancer treatmentmethod photodynamic therapy (PDT). The target molecule in 5-ALAPDTis protoporphyrin IX (PpIX), which is synthesized endogenously from5-ALA via the heme pathway in the cell. LÄS MER

  5. 5. Development and Application of a First Principle Molecular Model for Solvent Effects

    Författare :Anders Öhrn; Teoretisk kemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi; magnetisk resonans; Fysikalisk kemi; Physical chemistry; gränsskikt; Ytkemi; Surface and boundary layery chemistry; spektroskopi; egenskaper elektriska; magnetiska och optiska ; supraledare; Kondenserade materiens egenskaper:elektronstruktur; spectroscopy; relaxation; magnetic resonance; supraconductors; magnetic and optical properties; Kemi; Condensed matter:electronic structure; electrical; Solvent model; Solvochromatic shift; Chemistry; Solvent effects; Solvation; Intermolecular interactions; Quantum chemistry; Statistical mechanics;

    Sammanfattning : A considerable part of chemistry in nature and industry, takes place in an environment of other molecules. Reactions, transitions, interactions or other chemical processes are almost always modified by the environment. LÄS MER