Sökning: "CASSCF"

Visar resultat 1 - 5 av 13 avhandlingar innehållade ordet CASSCF.

  1. 1. An Ultrafast Spectroscopic and Quantum-Chemical Study of the Photochemistry of Bilirubin : Initial Processes in the Phototherapy for Neonatal Jaundice

    Författare :Burkhard Zietz; Tomas Gillbro; Jouko Korppi-Tommola; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bilirubin; Phototherapy; Neonatal Jaundice; Femtosecond Spectroscopy; CASSCF; TD-DFT; Isomerisation Dynamics; Biophysical chemistry; Biofysikalisk kemi;

    Sammanfattning : Bilirubin is a degradation product of haem, which is constantly formed in allmammals. Increased levels of bilirubin in humans lead to jaundice, a conditionthat is very common during the first days after birth. This neonataljaundice can routinely be treated by phototherapy without any serious sideeffects. LÄS MER

  3. 2. Multiconfigurational perturbation theory

    Författare :Kerstin Andersson; Karlstads universitet; []
    Nyckelord :Electron correlation; CASSCF; multiconfigurational second-order perturbation theory; CASPT2; ozone; C; N; O; F; Si; P; S; Cl; Ni; benzene; pyridine; pyrazine; pyrimidine; pyridazine; s-triazine; electric properties; excited states; spectroscopic data;

    Sammanfattning : The aim of the thesis is to analyze a method which describes the electron correlation in atoms and molecules. The method is based on Rayleigh-Schrödinger perturbation theory with a partitioning of the Hamiltonian into a fairly simple zeroth-order operator and a perturbation operator. LÄS MER

  4. 3. Extending the Reach of Accurate Wavefunction Methods

    Författare :Mickaël G. Delcey; Roland Lindh; Per-Åke Malmqvist; Martin Schütz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Density fitting; CASSCF; Analytical gradients; Photochemistry; X-ray spectroscopy; Kemi med inriktning mot kvantkemi; Chemistry with specialization in Quantum Chemistry;

    Sammanfattning : Multiconfigurational quantum chemistry methods, and especially the multiconfigurational self-consistent field (MCSCF) and multireference perturbation theory (MRPT2), are powerful tools, particularly suited to the accurate modeling of photochemical processes and transition metal catalysis. However, they are limited by their high computational cost compared to other methods, especially density functional theory. LÄS MER

  5. 4. Calculated Potential Energy Surfaces and Vibrational Analysis

    Författare :Niclas Forsberg; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Benzene; HCO; NEMO; Imaginary Level Shift; Double Harmonic Approximation; Potential Energy Surface; CASPT2; Franck-Condon Factors; CASSCF; p-Benzosemiquinone; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi;

    Sammanfattning : The focus of this thesis is on the calculation of potential energy surfaces and on the study of vibrational properties. For example: - We have developed a new method for calculation of Franck-Condon factors. - We have calculated full energy surfaces of the ground (X2A’) the excited (B2A’) states of the formyl radical. LÄS MER

  7. 5. Charge-transfer excitations and phtophysical properties of molecular building blocks

    Författare :Oscar Rubio Pons; Yi Luo; Antonio Rizzo; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; Photophysical porperties; CCSD; CASSCF; Teoretisk kemi; Theoretical chemistry; Teoretisk kemi;

    Sammanfattning : This thesis reports a state-of-the-art theoretical study of photophysical properties of organic charge-transfer aromatic molecules. These molecules are building blocks of molecular functional materials used in modern photonics technology and play essential roles in chemistry and biology in general. LÄS MER