Search for dissertations about: "time-dependent local density"

Showing result 1 - 5 of 16 swedish dissertations containing the words time-dependent local density.

  2. 1. Time-Dependent Many-Body Perturbation Theory: Possibilities and Limitations

    Author : Marc Puig von Friesen; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Many-body perturbation theory; Correlation functions; Hubbard model; Non-equilibrium Green s functions; Fysicumarkivet A:2011:Puig von Friesen;

    Abstract : This dissertation investigates the possibilities and limitations of time-dependent many-body perturbation theory by studying small Hubbard clusters for which the exact solution is available. The first part of the thesis is comprised of a short introduction to the concepts and methodologies used. READ MORE

  4. 2. Giant Dipole Resonances as Probes of Local Environment in Molecules, Clusters and Solidsl

    Author : Jarek Luberek; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; single center; photoionization; fullerene; coupled channels; LDA; giant dipole resonance; embedded; time-dependent local density;

    Abstract : In this thesis, I study effects of the local environment on the giant dipole resonances (GDR) in lanthanides and actinides. The effects of embedding in jellium, bonding in small molecules and incorporation into different fullerene systems are studied. READ MORE

  5. 3. Applications of diffusion MRI: Tensor-valued encoding, time-dependent diffusion, and histological validation

    Author : Jan Brabec; Lund Medicinsk strålningsfysik; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; diffusion MRI; meningioma; glioma; brain tumors; intracranial tumors; undulations; restricted diffusion; time dependence; spherical b-tensor encoding; linear b-tensor encoding; histogram analysis; anisotropic kurtosis; isotropic kurtosis; hyperintensity; conspicuity; white matter; detection; diffusion spectrum; consistency; type; grade; axon diameter; axonal trajectories; Fysicumarkivet A:2022:Brabec;

    Abstract : Diffusion MRI (dMRI) sensitizes the MR signal to the diffusion of water molecules at the microscopic level and thereby non-invasively probes tissue microstructure. This is relevant when determining biological properties of tissues, for example, cancer type and its malignancy. READ MORE

  6. 4. Formation and Dynamics of Molecular Excitons and their Fingerprints in Nonlinear Optical Spectroscopy

    Author : Pär Kjellberg; Kemisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; supraledare; magnetisk resonans; spektroskopi; Physical chemistry; Fysikalisk kemi; Photochemistry; Fotokemi; Kondenserade materiens egenskaper:elektronstruktur; magnetiska och optiska ; egenskaper elektriska; supraconductors; magnetic resonance; relaxation; spectroscopy; Fysik; Chemistry; Kemi; Condensed matter:electronic structure; electrical; Physics; Redfield relaxation theory ; Inhomogeneous broadening ; Time-dependent density functional theory ; Conjugated polymers ; Three-pulse photon echo ; Molecular excitons ; magnetic and optical properties; Nonlinear spectroscopy ;

    Abstract : An efficient transfer of energy in molecular systems has proven to be of fundamental importance both in nature and industrial applications. The ability of molecules to work together forming collective excitations, so-called excitons, plays a key role in for example the extraordinary fast energy transfer involved in the first steps of photosynthesis. READ MORE

  7. 5. Simulation of Core-Level Spectra of H-bonded Systems

    Author : Iurii Zhovtobriukh; Lars G.M. Pettersson; Anders Nilsson; Marcus Lundberg; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; water; x-ray absorption; non-resonant x-ray emission; damped linear response theory; time-dependent density functional theory; semi-classical approximation to Kramers-Heisenberg formula; Reverse Monte-Carlo; kemisk fysik; Chemical Physics;

    Abstract : The thesis consists of three related projects where attempts have been made to simulate X-Ray Absorption (XAS) spectra of water and hexagonal ice, static non-resonant X-ray Emission (XES) spectrum of water and to apply the semi-classical approximation to Kramers-Heisenberg formula (SCKH) formalism to calculate the non-resonant XES spectrum of water and methanol. The first project is devoted to an investigation of the performance of damped response theory in combination with the DFT electronic structure method (CPP-DFT) in XAS spectrum simulations of liquid water. READ MORE