Density functional-based tight-binding method

Frauenherm, T.. Seifert, G., Elstner, M., Hajnal, Z., Jungnickel. G.. Porezag. D.. Suhai. S.. and Scholz. R. 2000. A Self-consistent Charge Density-functional Based Tight-binding Method for Predictive Materials Simulations in Physics, Chemistry and Biology , Phys. Stat. Sol. B. 217. 41. 

Frauenheim T, Seifert G, Elstner M, Hajnal Z, Jungnickel G, Porezag D, Suhai S, Scholz R (2000) A self-consistent charge density-functional based tight-binding method for predictive materials simulations in physics, chemistry, and biology (2000) Physica Status Solid B 217 41-62 Espan ol P (1998) Fluid particle model. Phys Rev E 57 2930-2948... 

Finally, metallic allotropes with higher coordination numbers have been studied [39,51] and found to be well removed in enthalphy from four-fold coordinated structures below a pressure of 10 Mbar. Here, we report on the geometric optimization and doping properties of the recently proposed purely sp bonded carbon phases [15] and a propotype zeolite structure (sp bonded) called melanoph-logite using the density-functional based tight-binding method (DF-TB) [52,53]. 

Somewhat removed is the density functional based tight-binding method (DFTB), which is based on a second-order expansion of the Kohn-Sham total energy, employing a self-consistent redistribution of Mulliken charges (SCC-DFTB) (Elstner et al. 1998). It also employs dispersion corrections similar to the DFT-D method and has successfully been applied, e.g., to nuclear-base stacking problems (Elstner et al. 2001). 

As a consequence of the size limitations of the ab initio schemes, a large number of more-approximate methods can be found in the literature. Here, we mention only the density functional-based tight binding (DFTB) method, which is a two-center approach to DFT. The method has been successfully applied to the study of proton transport in perov-skites and imidazole (see Section 3.1.1.3). The fundamental constraints of DFT are (i) treatment of excited states and (ii) the ambiguous choice of the exchange correlation function. In many cases, the latter contains several parameters fitted to observable properties, which makes such calculations, in fact, semiempirical. 

AMI Semiempirical Austin method 1 CSA Conformational space annealing DFT Density functional theory DFTB Density-functional-based tight binding EA Evolutionary algorithm... 

The resulting density functional-based tight binding (DFTB) method works well for homo-nuclear systems, where the charge transfer between the atoms in the system does not occur or is... 

A self-consistent charge density functional based tight binding (SCC-DFTB) method was used for the calculations of the geometries, electronic... 

A compromise between computational effort and accuracy can be readied within an approximate KS-DFT scheme - a density functional based tight-binding (DFTB) method. This approximation assumes very strong atomic potential so that different atomic orbitals barely overlap. It can be considered the analog of the standard linear combination of atomic orbital (LCAO) approach with an LCAO representation of the KS orbitals. Like the LCAO approach, the atomic locations can be specified arbitrarily, so the method can be applied to nonperiodic (noncrystalline) materials. The fundamental step of the DFTB... 

Oliveira, AF., Seifert, G., Heine, T. Duarte, H.A. (2009) Density-functional based tight-binding An approximate dft method. Journal of the Brazilian Chemical Society, 20, 1193-1205. 

Oliveira AF, Seifert G, Heine T, Duarte HA (2009) Density-functional based tight-binding an approximate DFT method. J Braz Chem Soc 20 1193-1205. doi 10.1590/S0103-50532009000700002... 

Kruger T et al (2005) Validatitm of the density-functional based tight-binding approximation method for the calculation of reaction energies and other data. J Chem Phys 122 5... 

Within density-functional theory, a linear combination of overlapping non-orthogonal orbitals from first principles may be utilized to arrive at at full-potential local orbital (FPLO) method [213], and this k-dependent LCAO approach comes close to full-potential APW-based methods (see Sections 2.15.3 and 2.15.4) in terms of numerical accuracy, although FPLO is much faster simply because of the locality of the basis set. Even faster, due to a strongly simplified potential, is a parameter-free (density-functional) tight-binding method called TB-LMTO-ASA, derived through localization of a delocalized basis set (see Section 2.15.4). 

Methods particularly devoted to biomolecular processes are more frequently used than multipurpose semi-empirical molecular orbital methods like AMI and PM3. Self-consistent-charge density functional theory based tight-binding (SCC-DFTB), an efficient method derived from density functional theory, is well adapted for QM/MM studies of biomolecular systems."... 

Zhao et al. compared the structures of Si and Ge clusters for 25 < n < 33. They used an unbiased approach for identifying the structures of the global total-energy minima. This approach is based on a genetic-algorithm method combined with a parameterized tight-binding method. From the calculations they obtained a pool of 20 candidate structures. Subsequently, parameter-free, density-functional calculations were performed for those 20 structures, that then were allowed to relax locally. 

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