Sökning: "quantum chemical calculation"

Visar resultat 1 - 5 av 38 avhandlingar innehållade orden quantum chemical calculation.

  1. 1. Quantum Chemical Interpretation of Protein Crystal Structure

    Författare :Kristina Nilsson; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; structure; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi; protein; ComQum-X; Hess2FF; QM MM; hetero-compound; metal; oxidation state; protonation; force field; quantum refinement; refinement;

    Sammanfattning : An initial model in the crystallographic structure determination process, usually contains many errors. To produce an accurate model, one must carry out several cycles of crystallographic refinement. LÄS MER

  3. 2. Quantum dynamical effects in complex chemical systems

    Författare :S. Karl-Mikael Svensson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Quantum dynamics; Radiative association; Classical Wigner method; Feynman path integral; Reaction rate constants; Wigner phase space;

    Sammanfattning : When using mathematical models to computationally investigate a chemical system it is important that the methods used are accurate enough to account for the relevant properties of the system and at the same time simple enough to be computationally affordable. This thesis presents research that so far has resulted in three published papers and one unpublished manuscript. LÄS MER

  4. 3. Synthesis and development of compounds for nonlinear absorption of light

    Författare :Tomas Kindahl; Bertil Eliasson; Sascha Ott; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Platinum acetylide; nonlinear absorption; optical power limiting; oxazole; quantum chemistry calculation; quantum chemical calculation; triplet absorption; organisk kemi; Organic Chemistry; fysikalisk kemi; Physical Chemistry; Quantum Chemistry; kvantkemi;

    Sammanfattning : High-intensity light — for instance that from a laser — can be destructive, not only to the human eye, but also to equipment such as imaging sensors and optical communication devices. Therefore, effective protection against such light is desirable. LÄS MER

  5. 4. Quantum Mechanical Studies of Electron Transport Processes Including Superconductivity

    Författare :Agris Klimkans; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum chemical calculations; ab initio; electronic;

    Sammanfattning : Processes of electron transfer, charge and spin localization, and electron pair transfer have been studied on the basis of the Marcus model and with the help of accurate quantum chemical calculations. A vibrational model, based on the corrections to the Born-Oppenheimerapproximation, which applies in the case of a vanishing barrier in the Marcus model, has been proposed. LÄS MER

  7. 5. Matrix Algebra for Quantum Chemistry

    Författare :Emanuel H. Rubensson; Pawel Salek; Stefan Goedecker; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; linear scaling; reduced complexity; electronic structure; density functional theory; Hartree-Fock; density matrix purification; congruence transformation; inverse factorization; eigenvalues; eigenvectors; numerical linear algebra; occupied subspace; canonical angles; invariant subspace; Theoretical chemistry; Teoretisk kemi;

    Sammanfattning : This thesis concerns methods of reduced complexity for electronic structure calculations.  When quantum chemistry methods are applied to large systems, it is important to optimally use computer resources and only store data and perform operations that contribute to the overall accuracy. LÄS MER