DFTB
DFTB, short for Density Functional Tight Binding, is a semi-empirical quantum mechanical method derived from density functional theory (DFT). It aims to retain the essential physics and accuracy of DFT while reducing computational cost by using a tight-binding-like Hamiltonian and a minimal, atom-centered basis set.
The method expands the DFT total energy in deviations of the electron density from a reference state
DFTB has several levels, such as DFTB0, DFTB2, and DFTB3, corresponding to the order of the density
Applications of DFTB span large-scale systems, from nanostructures and surfaces to polymers and biomolecules, where conventional
Limitations include dependence on parameter sets and transferability, reduced accuracy for systems poorly represented in reference