Search for dissertations about: "multiconfigurational quantum chemistry"

Showing result 1 - 5 of 7 swedish dissertations containing the words multiconfigurational quantum chemistry.

  1. 1. Studies of molecular systems with multiconfigurational methods

    Author : Jonna Stålring; Beräkningskemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; excited state geometry optimizations; multiconfigurational methods; two-photon transition intensities; the C3H2 isomers; quantum chemistry; spectroscopy; Teoretisk kemi; Theoretical chemistry; kvantkemi; the ammonia dimer interaction energy;

    Abstract : Research in theoretical chemistry is aimed at finding computational algorithms that produce as accurate results as possible, for as large molecules as possible, with a minimum of computational effort and to apply these methods to molecular systems of chemical interest. The most accurate theoretical methods, often referred to as ab initio methods, are derived from the fundamental laws of physics and they do not rely on any empirical information. READ MORE

  2. 2. Extending the Reach of Accurate Wavefunction Methods

    Author : Mickaël G. Delcey; Roland Lindh; Per-Åke Malmqvist; Martin Schütz; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  3. 3. Towards a multiconfigurational description of the electronic structure in solids

    Author : Ernst Dennis Larsson; Beräkningskemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Embedding; Solids; Ionic; ab-initio model potentials; multiconfigurational quantum chemistry; SCEPIC;

    Abstract : Materials of ionic crystals are ubiquitous in industrial chemistry.For example, materials such as cerium dioixde (CeO2) are used in both self-cleaning ovens and to clean exhaust fumes from cars.Other materials, such as titanium dioixde (TiO2) has been used in the solar-cell industry.So-called garnets are used in several lasers. READ MORE

  4. 4. Calculated Potential Energy Surfaces and Vibrational Analysis

    Author : Niclas Forsberg; Beräkningskemi; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 5. Fundamental interactions in transition metal reactions

    Author : Michael R. Coates; Michael Odelius; Markus Kowalewski; Abhik Ghosh; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; quantum chemistry; electronic structure; multiconfigurational; density functional theory; molecular dynamics; excited state molecular dynamics; non-adiabatic dynamics; solvation; organometallic complexes; x-ray absorption spectroscopy; photoelectron spectroscopy; time-resolved spectroscopy; femtosecond; picosecond; kemisk fysik; Chemical Physics;

    Abstract : Transition metal complexes that participate in homogeneous reactions often perform the role of a catalyst, facilitating novel reaction pathways. When these complexes are pushed away from their equilibrium, the arrangement of the coordinating ligands around the metal center is perturbed and new reaction pathways are opened. READ MORE