Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 8 of 8 for “"exact exchange"”.
-
Hybrid density functionals with proper exact exchange
… design, hybrid DFAs are supposedto use the exact exchange (EXX). However, when hybrid functionals were originally intro-duced, there was no simple method to compute EXX, so all of their practical implementationsstarted using the Hartree–Fock exchange (HFX), which can be computed easily and …
-
Orbital-dependent exchange-correlation functionals in density-functional theory realized by the FLAPW method
… (DFT), to orbital-dependent functionals for the exchange-correlation (xc) energy. In contrast to the commonly applied local-density approximation (LDA) and generalized gradient approximation (GGA) for the xc energy, orbital-dependent functionals depend directly on the Kohn-Sham (KS) orbitals and …
-
Weak interactions and excited states from Coulomb-attenuated DFT
… coupled with good accuracy. Although formally exact, approximations are required when practically applied. In the Kohn-Sham formalism, these approximations are contained within the exchange-correlation functional. Well established exchange-correlation functionals, such as the ubiquitous B3LYP, …
-
Real time density functional simulations of quantum scale conductance
… spin are highly dependent upon the amount of exact exchange included in the approximate exchange-correlation energy functional. This functional dependence is further illustrated when we demonstrate that the conductance gap of a device imperfectly coupled to wires varies based upon the …
-
Development of more accurate computational methods within linear-scaling density functional theory
… Regardless of scaling DFT has limitations as the exact exchange-correlation functional (a key term in the Kohn-Sham equations) is not known and so approximations have to be made. These approximate functionals generally describe dispersion interactions poorly. In this thesis empirical corrections …
-
Multifidelity Methods for Design of Transition MetalComplexes
… DFT calculations with different fractions of exact exchange, and a novel uncertainty metric for data-driven discovery is proposed that quantifies the ability of ANNs to generalize to unseen data based on similarity in the learned latent space. This metric is shown to offer superior performance …
-
Exchange-Correlation Kernels Within Time-Dependent Density Functional Theory For Ground-State and Excited-State Properties
The exact exchange-correlation 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 …
-
Electronic and optical properties of silicon based semiconductors with reduced dimension: a theoretical study
Submitted by Meng Tao (mengtao2@illinois.edu) on 2012-11-14T16:22:31Z No. of bitstreams: 1 Qian_Gefei.pdf: 642631 bytes, checksum: 8b110df39151febc039311918fbf9896 (MD5)