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Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases.
DMol 3 is a commercial (and academic) software package which uses density functional theory with a numerical radial function [1] basis set to calculate the electronic properties of molecules, clusters, surfaces and crystalline solid materials [2] from first principles.
In practice, the density functional is known exactly except for two terms. These are the electronic kinetic energy and the exchange – correlation energy. The lack of the true exchange–correlation functional is a well known problem in DFT, and there exists a huge variety of approaches to approximate this crucial component.
The linearized augmented-plane-wave method (LAPW) is an implementation of Kohn-Sham density functional theory (DFT) adapted to periodic materials. [1] [2] [3] It typically goes along with the treatment of both valence and core electrons on the same footing in the context of DFT and the treatment of the full potential and charge density without any shape approximation.
They may also include density functional theory (DFT), molecular mechanics or semi-empirical quantum chemistry methods. The programs include both open source and commercial software. Most of them are large, often containing several separate programs, and have been developed over many years.
The Density Functional Based Tight Binding method is an approximation to density functional theory, which reduces the Kohn-Sham equations to a form of tight binding related to the Harris functional. The original [ 1 ] approximation limits interactions to a non-self-consistent two center hamiltonian between confined atomic states.
Download as PDF; Printable version; In other projects ... Pages in category "Density functional theory" ... Orbital-free density functional theory; P. Pulay stress; R ...
The kinetic energy expression of Thomas–Fermi theory is also used as a component in more sophisticated density approximation to the kinetic energy within modern orbital-free density functional theory. Working independently, Thomas and Fermi used this statistical model in 1927 to approximate the distribution of electrons in an atom.