Essays about: "täthetsfunktionalteori"
Showing result 1 - 5 of 12 essays containing the word täthetsfunktionalteori.
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1. First principles investigation of the thermal conductivity of Zr, ZrC, and ZrN
University essay from KTH/FysikAbstract : The thermal conductivity and electrical resistivity of Zr, ZrC, and ZrN were calculated using first-principles density functional theory (DFT) and the Boltzmann transport equation. The electron-phonon scattering was modeled via the self-energy relaxation time approximation (SERTA), and the phonon-phonon scattering via the analogous single-mode relaxation time approximation (SMRTA). READ MORE
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2. Photophysics of the polymer acceptor PF5-Y5 in organic photovoltaics : A first principles theory based study
University essay from Karlstads universitet/Institutionen för ingenjörsvetenskap och fysik (from 2013)Abstract : Non-fullerene Acceptors (NFAs) have gathered a great deal of interest for use inorganic photovoltaics (OPVs) due to recent breakthroughs in their power conversion efficiency and other advantages they offer over their Fullerene-based counterparts. In this work, a new promising non-fullerene polymer acceptor, PF5-Y5, have been studied using density functional theory and time-dependent density functional theory; and the effects that oligomer length, geometry relaxation and exchange-correlation interaction has on the exciton binding energies (the difference between optical and fundamental energy gaps) have been investigated. READ MORE
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3. Study of hole mobility in amorphous polyethylene via kinetic Monte Carlo methods
University essay from KTH/Matematik (Avd.)Abstract : This thesis presents a study of hole mobility in amorphous polyethylene using kinetic Monte Carlo (KMC) methods together with a novel chain segmentation model developed by Unge and Nilsson, which determines hole localization sites based on torsion angles along the polymer chain. An extension to the KMC algorithm was developed which improves performance by modelinground-trips between strongly interconnected localization sites. READ MORE
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4. First principles DFT study of polyethylene insulation containing chemical impurities - implementing counterpoise correction
University essay from KTH/Tillämpad fysikAbstract : Density functional theory (DFT) calculations of polyethylene (PE) HVDC cable insulation have been performed for systems containing four different chemical impurities: acetophenone, cumene, $\alpha$-methyl styrene and $\alpha$-cumyl alcohol. Systems were generated by molecular dynamics (MD) equilibration at four different temperatures relevant for cable insulation applications: 277 K, 293 K, 343 K and 363 K. READ MORE
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5. Machine-Learning for Lattice Models in and out of Equilibrium
University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionenAbstract : Machine-learning methods have in recent years seen a great deal of use in condensed matter physics. In this thesis we apply such methods, specifically machine-learning with artificial neural networks, to the equilibrium and non-equilibrium description of the Hubbard and Hubbard-Holstein models. READ MORE
