DENSITY FUNCTIONAL THEORY - DFT

Density functional theory (DFT, called density functional theory) - pillar several quantum-mechanical methods, used for modeling the structure of chemical molecules or crystals. These methods are alternatives to methods based on the wave functions.
This theory assumes that all properties of a quantum system in a steady state due to the electron density of the ground state. More specifically, it is assumed that all observables are functionals unequivocal electron density of the ground state.
At steady state the potential for movement of outer electrons (the potential of the atomic nuclei or the external electrostatic potential) is independent of time. An extension of DFT for states with varying external potential, such as a sinusoidal alternating current, derived from electromagnetic wave is TDDFT (time-dependent density functional theory). DFT theory is based on two Hohenberg-Kohn theorems.
Density functional theory (DFT) calculations have been used to investigate the physical orign of the perturbation to NMR chamical shifts upon protein binding.

Softwares for Density Funtional Theory

DFT is supported by many quantum chemistry and solid state physics softwares, oftem along with other methods. Versatile sofware pakages for DFT include: the Vienna Ab initio Simulation Package (VASP), QUANTUM-ESPRESSO, ABINIT, GPAW, Gaussian and BigDFT.