Essays about: "time-dependent density functional theory"

Showing result 1 - 5 of 6 essays containing the words time-dependent density functional theory.

  1. 1. 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)

    Author : Anton Almén; [2022]
    Keywords : PF5-Y5; Non-fullerene-acceptor; NFA; polymer; fundamental; optical; gap; oxidation; reduction; exciton; binding; energy; oligomer; length; PF5-Y5; Non-fullerene-acceptor; NFA; polymer; fundamentalt; optiskt; gap; oxidation; reduktion; exciton; binding; energi; oligomerlängd;

    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

  2. 2. Charge transfer states at polymer solar cell interfaces : Insights from atomic-scale modeling

    University essay from Karlstads universitet/Institutionen för ingenjörsvetenskap och fysik (from 2013)

    Author : Rickard Svensson; [2022]
    Keywords : organic solar cells; OSC; polymer; interface; charge transfer; non-fullerene acceptor; PYT; PBDB-T; DFT; TD-DFT; conformation; alkyl groups; methylation; HOMO; LUMO; FMO; NTO; UV-Vis; DOS; exciton; exciton binding energy; dipole moment; open-circuit voltage; organiska solceller; OSC; polymer; gränssnitt; laddningsöverföring; icke-fullerenacceptor; PYT; PBDB-T; DFT; TD-DFT; konformation; alkylgrupper; metylering; HOMO; LUMO; FMO; NTO; UV-Vis; DOS; exciton; excitonbindningsenergi; dipolmoment; tomgångsspänning;

    Abstract : Organic solar cells (OSCs) based on non-fullerene acceptors (NFAs) have attracted a great deal of attention in recent years due to their rapidly increasing efficiency and enormous potential. In this work, the optical and electronic properties of systems containing the very promising non-fullerene acceptor PYT have been thoroughly studied with the use of the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). READ MORE

  3. 3. Machine-Learning for Lattice Models in and out of Equilibrium

    University essay from Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

    Author : Johannes Sandberg; [2021]
    Keywords : Physics and Astronomy;

    Abstract : 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

  4. 4. Structural integrity of highly ionized peptides

    University essay from Uppsala universitet/Molekyl- och kondenserade materiens fysik

    Author : Ibrahim Eliah Dawod; [2019]
    Keywords : X-ray free-electron laser; X-ray imaging; XFEL; Computer simulations; Radiation damage; Ab-initio molecular dynamics; DFT; TDDFT; Excited states; Femtosecond; Bioimaging;

    Abstract : In order to understand the behaviour and function of proteins, their three dimensional structure needs to be known. Determination of macro-molecules’ structures is done using X-ray diffraction or electron microscopy, where the resulting diffraction pattern is used for molecular reconstruction. READ MORE

  5. 5. IR spectroscopy for vibrational modes : A semi-classical approach based on classical electrodynamicsand modern quantum mechanics

    University essay from Linnéuniversitetet/Institutionen för fysik och elektroteknik (IFE)

    Author : Ulf Oreborn; [2018]
    Keywords : ;

    Abstract : The atoms of a molecule are always restless and are constantly moving in one way or another.Apart from rotations and translations, they may vibrate in many different modes. They may moveradially toward or from each other, so called stretching. This can be done symmetrically or asymmetrically. READ MORE