Density-functional tight-binding: basic concepts and applications to molecules and clusters

Abstract

The scope of this article is to present an overview of the Density Functional based Tight Binding (DFTB) method and its applications. The paper introduces the basics of DFTB and its standard formulation up to second order. It also addresses methodological developments such as third order expansion, inclusion of non-covalent interactions, schemes to solve the self-interaction error, implementation of long-range short-range separation, treatment of excited states via the time-dependent DFTB scheme, inclusion of DFTB in hybrid high-level/low level schemes (DFT/DFTB or DFTB/MM), fragment decomposition of large systems, large scale potential energy landscape exploration with molecular dynamics in ground or excited states, nonadiabatic dynamics. A number of applications are reviewed, focusing on -(i)-the variety of systems that have been studied such as small molecules, large molecules and biomolecules, bare or functionalized clusters, supported or embedded systems, and -(ii)-properties and processes, such as vibrational spectroscopy, collisions, fragmentation, thermodynamics or non-adiabatic dynamics. Finally outlines and perspectives are given. ARTICLE HISTORY

Structural, dynamical, and photochemical properties ofortho-tetrafluoroazobenzene inside a flexible MOF under visible light irradiation

“…This comparably large system size containing a total of 2320 electrons already proves too demanding for a picosecondscale molecular dynamics study employing density functional theory (DFT). However, the increasingly successful density functional tight binding (DFTB) approach, 55,56 representing a DFT-parametrized variant of tight binding (TB) theory, 57 proved as a viable alternative to balance the accuracy of results and the associated computational demand. In this work, selfconsistent charge density functional tight binding (SCC DFTB) 58,59 interfaced to our in-house developed molecular dynamics simulation engine [60][61][62] was applied to study the properties of the E and Z isomers of tF-AZB in the DMOF-1 host lattice.…”

Dependence upon charge of the vibrational spectra of small Polycyclic Aromatic Hydrocarbon clusters: the example of pyrene

“…Several schemes have been developed to correct those artifacts, such as the long-range shortrange schemes which allow to treat differently the short dynamical correlation and the long-range non-dynamical correlation [63][64][65][66]. Similar implementations have been done [67] with the context of Density Functional based Tight Binding (DFTB [68][69][70][71]), an approximation of DFT which is computationally more efficient than DFT and able to deal with larger systems. Other schemes can be used to avoid overdelocalization problems in charged molecular clusters.…”

Roadmap on dynamics of molecules and clusters in the gas phase

“…For larger systems and/or longer simulation times, AIMD can be replaced by the self-consistent charge density functional tight binding (SCC-DFTB) method [127]. As previously mentioned, maximum simulation times available for quantum chemistry molecular dynamics are of the order of few ps; however, those can be extended until a nanosecond with SCC-DFTB methodology and still provide reliable results [128].…”