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Showing 1 to 20 of 20 for “"Time-dependent DFT"”.
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Computational Studies on Bimetallic Catalysis and X-ray Absorption Spectroscopy
… (AWS) is discussed. Density functional theory (DFT) studies were used for bimetallic catalysis and time-dependent DFT studies were used for excited state dynamics. These studies were performed using Gaussian 09 package and NWChem. Hydroformylation is experimentally performed in acetone and 30% …
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Synthesis, Linear and Nonlinear Photophysical Characterization of Two Symmetrical Pyrene-terminated Squaraine Derivatives in Solution
… The experimental results were compared with time-dependent DFT calculations. These observations propose a new trend in the formulation of highly absorbing organic molecules containing pyrenyl groups for the development of new materials with Organic Light-Emitting Diode (OLED) applications. …
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Excited states and electron transfer in solution : models based on density functional theory
… approaches based on density functional theory (DFT) to predict excitation energies and electron transfer parameters in organic chromophores and semiconductors in solution. First, we apply constrained DFT to characterize charge recombination in a photoexcited donor-acceptor dyad and to understand …
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Nonspectator Reactivity of Nontrigonal Tricoordinate Phosphorus Ligands
… K-edge XANES spectroscopy combined with time-dependent DFT calculation reveal ca. 1.5 eV bathochromic shift in the position of P K-edge onset. In Chapter 3, the development of nonspectator reactivities of a novel chelating ligand containing a nontrigonal P(III) center with Group 8 Ru …
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Computational methods for small-molecule transparent semiconductors
… tools — namely density functional theory (DFT) and graph neural networks — to gain a deeper understanding of how molecular structure impacts macroscopic optical properties and suggest directions for future study. In this work we employ linear-response time-dependent DFT with optimally tuned …
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Systematic improvement and applications of density functional theory in complex chemical systems
Density functional theory (DFT) has become the de facto method for quantum mechanical simulations of molecules and solids because of its high performance to cost ratio. In this thesis, we discuss two aspects of DFT simulations in complex chemical systems: systematic improvement of the accuracy of …
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Computational investigations of the electronic structure of molecular actinide compounds
… density functional theory. The reason for using DFT instead of other methods is mainly due to the size of the compounds which makes multireference calculations prohibitively expensive, but also to make comparisons with previously calculated DFT results. The first chapter presents the basic …
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Ab initio modelling of photoinduced electron dynamics in nanostructures
… TMD (i.e. density functional theory (DFT) and many-body perturbation theory) may not be applied to the full TMD-MNP structure as the MNP is often on a much larger scale than the semiconductor rendering the ab initio methods infeasible.<br/><br/>In this thesis, we develop a dynamical, …
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Computational investigation on polycyclic aromatic hydrocarbons in the molecular and solid phases
… We used all-electrons density functional theory(DFT)and time- dependent DFT(TDDFT)to quantify the effects of morphology and chemical modifications ondifferent physical observables, namely electron affinity,ionization energy,quasi-particleenergy gap,optical absorption,excitonbindingenergy, and …
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Taming the Inverse and Forward Problems in Density Functional Theory
… of ground-state density functional theory (DFT) constitutes finding the ground-state density $n(x)$ that minimises a Kohn-Sham total energy functional defined using some exchange-correlation (xc) functional $E_\text{xc}[n]$. Towards this end, the associated Euler-Lagrange equations, i.e. the …
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Modeling Dark- and Light-Induced Crystal Structures and Single-Crystal Optical Absorption Spectra of Ruthenium-Based Complexes that Undergo SO2-Linkage Photoisomerization
… a Plane-Wave (PW) – Density Functional Theory (DFT) based periodic methodology that can effectively model the dark- and light-induced structures, and single-crystal optical absorption spectra of these complexes. Initially, these crystalline materials are modeled via PW-based periodic and …
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Orbital Functionals in Time-Dependent Density-Functional Theory
… functionals in density-functional theory (DFT). After a short introduction the basic ideas of static and time-dependent DFT are presented in Chap. 2. In this chapter the advantages and disadvantages of common approximations for the exchange-correlation (xc) functional are also discussed as …
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DENSITY FUNCTIONAL THEORY STUDIES OF PHOTOINDUCED ELECTRON EXCITATION AND TRANSFER OF ORGANIC DYES FOR PHOTODYNAMIC THERAPY, SOLAR CELLS, AND FLUORESCENCE SENSOR APPLICATIONS
… results. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed to understand the photophysical processes in the porphyrin-perylene bisimide (HTPP-PDI) dyad that exhibited long-lived triplet states. The DFT results show that breaking the rigidity of …
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Weak interactions and excited states from Coulomb-attenuated DFT
Density functional theory (DFT) is currently the most widely applied electronic structure theory in Chemistry. It is favoured for its computational efficiency, coupled with good accuracy. Although formally exact, approximations are required when practically applied. In the Kohn-Sham formalism, …
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Luminescent Properties of Anthracene-based Metal-Organic Frameworks
… steady-state emission spectroscopy and time-correlated single photon counting (TCSPC) emission lifetime spectroscopy. The addition of carboxylic acid functional groups on the anthracene ring alters photophysical properties to varying degrees depending on the location and protonation …
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Quantum Chemical Studies for the Engineering of Metal Organic Materials
… PM7 Hamiltonian and, Density Functional Theory (DFT) to predict the geometry and electronic structure of the ground state, and Time Dependent DFT (TD-DFT) to predict the excited states and the optical properties. The molecular absorption capacity of aldoxime coordinated Zn(II) based MOMs …
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Exchange-Correlation Kernels Within Time-Dependent Density Functional Theory For Ground-State and Excited-State Properties
… kernel is a functional derivative of the exact time-dependent exchange-correlation (XC) potential with respect to the time-dependent density, evaluated at the ground-state density. As the XC potential is not known, the exact kernel is also unavailable. Therefore, it must be modeled either using …
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The Electronic and Vibrational Spectroscopy of Matrix-Isolated Phthalocyanines – Experiment and Theory
… basis set ab initio density functional theory (DFT) calculations, allow identification of the in-plane (IP) bending mode of H2Pc at 1045 cm-1 and the out-of-plane (OP) bending mode at 765 cm-1. The antisymmetric N-H stretching mode observed at ~3310 cm-1 in low temperature solids is slightly …
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Structure-property relationships of dyes as applied to dye-sensitized solar cells
… methods, including density functional theory and time-dependent density functional theory, are used to validate and predict the optical and electronic properties of dye molecules, in their isolated state and once embedded into a working electrode device environment that comprises a dye…TiO2 …