Density functional tight-binding technique

The molecular geometry of swainsonine (378) has been modeled with the aid of the density functional tight-binding (DFTB) technique as a prelude to computing its intercalation into DNA. The calculations, the first of their kind, showed the alkaloid to be a good electron acceptor toward... 

Preliminary models of the surface topography, for example, can be determined by atomic-probe methods, ion-scattering, electron diffraction, or Auger spectroscopy. The chemical bonds of adsorbates can be estimated from infrared spectroscopy. The surface electronic structure is accessible by photoelectron emission techniques. In case the surface structure is known, its electronic structure has to be computed with sophisticated methods, where existing codes more and more rely on first principles density functional theory (DFT) [16-18], or, in case of tight-binding models [19], they obtain their parameters from a fit to DFT data [20]. The fit is not without ambiguities, since it is unknown whether the density of states used for the fit is really unique. 

These nanostructures are described using a single-band tight-binding Hamiltonian and their electronic conductance and density of states are calculated within the Green s function formalism based on real-space renormalization techniques (Rosales et al. 2008). 

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