Search for dissertations about: "B3LYP method"

Showing result 1 - 5 of 16 swedish dissertations containing the words B3LYP method.

  2. 1. Photophysical Properties of Organic and Organometallic molecules

    Author : Oscar Rubio Pons; KTH; []
    Keywords : molecule; two-photon absorption; singlet-triplet. spin-orbit; CASSCF; emission; phosphorescence; DFT; B3LYP;

    Abstract : Highly correlated quantum chemical methods have been appliedto study the photophysical properties of substituted benzenes.With the inclusion of spin-orbit coupling, the phosphorescencesof these molecules have been calculated usingMulti-CongurationalSelf- Consistent Field (MCSCF) quadraticresponse theory. READ MORE

  4. 2. Theoretical studies of blue copper proteins

    Author : Mats H M Olsson; Beräkningskemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; quantum chemistry; metal-thiolate bonds; axial ligation; electron transfer proteins; reduction potential; reorganisation energy; Cu II ; Cu I ; strain; Induced-rack theory; Entatic state theory; cytochrome c oxidase; CuA; nitrite reductase; azurin; Blue copper proteins; plastocyanin; B3LYP; CASPT2; Soil Science; agricultural hydrology; Lantbrukshydrologi; marklära;

    Abstract : In this thesis, a critical investigation is presented about the role of mechanical strain for the electron-transfer properties of the blue copper proteins. It has been found that the structure of a realistic model complex of the oxidised blue-copper active site, optimised in vacuum with the B3LYP method, has the same trigonal cupric geometry as in the protein. READ MORE

  5. 3. Theoretical Modeling of Enzyme Catalysis with Focus on Radical Chemistry

    Author : Vladimir Pelmenschikov; Per E. M. Siegbahn; Tim Clark; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; density functional theory; enzyme catalysis; radical chemistry; zinc-containing peptidase; methyl-coenzyme M reductase; ribonucleotide reductase; superoxide dismutase; Quantum chemistry; Kvantkemi;

    Abstract : Hybrid density functional theory (DFT) B3LYP method is applied to study the four diverse enzyme systems: zinc-containing peptidases (thermolysin and stromelysin), methyl-coenzyme M reductase, ribonucleotide reductases (classes I and III), and superoxide dismutases (Cu,Zn- and Ni-dependent enzymes). Powerfull tools of modern quantum chemistry are used to address the questions of biological pathways at their molecular level, proposing a novel mechanism for methane production by methyl-coenzyme M reductase and providing additional insights into hydrolysis by zinc peptidases, substrate conversion by ribonucleotide reductases, and biological superoxide dismutation. READ MORE

  6. 4. Quantum Chemical Modeling of Enzymatic Methyl Transfer Reactions

    Author : Polina Georgieva; Fahmi Himo; Nino Russo; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; reaction mechanism; Theoretical chemistry; Teoretisk kemi;

    Abstract : In this thesis, quantum chemistry, in particular the B3LYP density functional method, is used to investigate a number of methyl transfer enzymes. Quantum chemical methodology is today a very important tool in the elucidation of properties and reaction mechanisms of enzyme active sites. READ MORE

  7. 5. Nitrile Hydratases and Epoxide-Transforming Enzymes : Quantum Chemical Modeling of Reaction Mechanisms and Selectivities

    Author : Kathrin Hopmann; Fahmi Himo; Nigel G. Richards; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biochemistry; Biokemi;

    Abstract : Quantum chemical studies of enzymatic reactions are able to provide detailed insight into mechanisms and catalytic strategies. The energetic feasibility of proposed mechanisms can be established, and new possible reaction pathways can be put forward. READ MORE