Chapter 12 - Main concepts and applications of DFTB approach

Abstract

Currently, the density functional based tight binding (DFTB) method is widely used and very important in the material and technology sciences. This is due to the DFTB-based theoretical calculation being around 100–1000 times faster than the density functional theory (DFT), having low cost, being more accurate, and providing calculations which are 96–99% close to the experimental results. DFTB is based on a second-order development of the Kohn–Sham total energy in DFT. In this chapter, the basic concepts of DFTB such the minimal atomic basis set, matrix elements, total energy, expanded total energy in DFTB, as well as second- and third-order DFTB versions are reviewed. The modern DFTB applications including the atomic clusters, molecular clusters, nanoparticles, crystals, corrosion inhibitors, molecular dynamic (MD) simulations, thermodynamics, and vibrational spectra are reviewed.