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Showing 1 to 14 of 14 for “"Density functional approximations"”.
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Towards Systematic Improvement of Density Functional Approximations
<p>Density functional theory is a formally exact theory to describe ground state properties due to the existence of the exact functional. In practice, the usefulness of density functional theory relies on the accuracy of density functional approximations. After decades of effort of functional …
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Wannier Functions and Their Role in Improving Density Functional Approximations
<p>Density functional theory has proven to be an invaluable tool for modeling matter and chemistry . This can be seen from the fact that density functional theory papers are far and away the most cited theory from the physical sciences. While density functional theory excels at predicting total …
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Construction of first-principles density functional approximations and their applications to materials
Kohn-Sham density functional theory is a rigorous formulation of many-electron quantum mechanics which, for practical purposes, requires approximation of one term in its total energy expression: the exchange-correlation energy. This work elucidates systematic methods for constructing approximations …
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Assessment of the scaled Perdew-Zunger self-interaction correction applied to three levels of density functional approximations
The Kohn-Sham density functional theory (KS-DFT) finds an approximate solution for the many-electron problem for the ground state energy and density by solving the self-consistent one-electron Schr\"{o}dinger equations. KS-DFT would be an exact theory if we could find the precise form of …
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Density-to-Potential Inversions in Density Functional Theory
Density functional theory and many of its extensions are formally exact quantum many-body theories. In practice, however, implementations of these theories use approximations for all but the most trivial systems. We present a set of inversion methods to numerically compute the exact potentials …
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Accurate Computation Of Molecular Properties From Novel Applications Of Quantum Mechanical Wavefunction Methods
… methods including ab initio methods, various density functional approximations and water potentials. Lastly, anharmonic vibrational frequencies and dissociation energies have been computed for small hydrogen-bonded dimers, allowing for a direct comparison to experiment.
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Charge and excitation-energy transfer in time-dependent density functional theory
… is of practical relevance. In principle, density functional theory (DFT) and time-dependent density functional theory (TDDFT) appear as natural choices to study the relevant sizable molecules on a first-principles scale at bearable computational cost. However, the application of standard …
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It's Not a SKZCAM! Accurate Surface Chemistry at Low Cost
… will require going beyond the standard density functional theory (DFT) to methods like coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. However, the high computational cost of CCSD(T) typically necessitates the use of embedded cluster models, …
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Quantum Chemistry Meets Machine Learning: Autonomous Computational Workflow for Chemical Discovery
… on these data sets as either surrogate function approximations or generative models, accelerated chemical discovery for functional molecules and materials are achieved. Current automation workflows, however, are far from perfect. Namely, they produce too many unfruitful results and suffer …
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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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Implementation and reassessment of the Perdew-Zunger self-interaction correction
Density functional theory (DFT) using semi-local functional approximations can describe many chemical properties to high accuracy, but in some cases large and even qualitative errors emerge. Some of these errors are ascribed to an unphysical interaction of each electron with itself, which is …
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Correcting the Self-Interaction Error of Approximate Density Functionals
Common density functional approximations (DFAs) for the exchange-correlation energy suffer from self-interaction error (SIE), which is believed to be the cause of many of the failures of these approximations, such as poor description of charge transfer and transition states of chemical reactions. …
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Importance of Self-Interaction Correction in Hydrogen-Bonded Water Clusters and Water-Ion Clusters
Density functional theory is the most commonly used computational tool to study properties of solids and molecules. Self-interaction error, that arises due to improper cancellation of the self-Hartree and the self exchange correlation energy, has long been identified as a major limitation of …
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Theoretical and Computational Aspects of the Optimized Effective Potential Approach within Density Functional Theory
<p>The computational success of density functional theory relies on the construction of suitable approximations to the exchange-correlation energy functional. Use of functional approximations depending explicitly upon the density alone appear unable to address all aspects of many-body interactions, …