The density-functional tight-binding (DFTB) method [1] is an approximation to density functional theory (DFT) allowing a speedup of first principles electronic structure calculations by two to three orders of magnitude. This is achieved by solving the Kohn-Sham equations for valence electrons using a parameterized two-center Hamiltonian in a minimum pseudoatomic orbital basis set. Since electronic structure is explicitly computed for each atomic configuration, DFTB is capable of simulating chemical processes including the breaking of covalent bonds, changes in aromatic electronic structure, charge transfer, charge polarization, etc. [2]. DFTB methods can therefore be employed in atomistic molecular dynamics (MD) simulations of processes that involve complex chemical processes, electron transfer, and/or mass and ion transport. The parameterization of interatomic interactions involving transition metal elements in the DFTB framework is complex and requires chemical intuition and large and reliable reference datasets. In this presentation I will discuss two recent parameter sets we developed, namely the Au-P interaction for phosphine-stabilized nanoscale gold clusters [3] and the Pt-titania interaction for TiO2-supported platinum catalysts nanoparticles [4].

Density-functional tight-binding for nanoscale transition metal systems

ACS Fall 2021

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