Tiger Team Projects
The following enumeration provides an overview of collaborations between members of the bwHPC-S5 team and scientists, i.e. tiger teams. To apply for support by a tiger team, click
Extension of van der Waals D3 method for better description of metal metal interactions in metallic systems
With including pair-wise van der Waals interactions as proposed by Grimme , intermolecular and molecule/surface interactions can be evaluated more accurately in VASP. In contrast to conventional DFT and hybrid DFT functionals, which do not explicitly incorporate dispersion interactions, the Grimme’s D3 method has been designed to describe the dispersion interactions accurately on top of DFT calculations . Nevertheless in our own studies we have found noticeable deficiencies of the D3 method when being applied to metal metal interactions in metallic systems. This is due to the fact that the D3 coefficients have been designed for metal complexes in molecular systems, but not for metals in metallic solids. Therefore we have extended the functionality of the D3 implementation in VASP giving the user the choice to selectively disable the D3 contributions of certain atoms or types of pari-interactions. This approach is promising since the metal metal interaction in metallic systems can already be well described by conventional DFT methods. Furthermore we have upgraded the D3 implementation in VASP incorporating latest corrections to D3 theory. In principle the implementation of this has been straight forward, but problems in early implementations of D3 theory lead to inconsistent results in some cases. In addition unfavorable placement of the selection mechanisms caused scaling problems in first implementation attempts. After overcoming these problems, recent studies confirmed that the modifications indeed can result in the desired improvement of molecule to metallic surface interactions . Literature:  S. Grimme, J. Antony, S. Ehrlich, and S. Krieg, A consistent and accurate ab initio parametrization of density functional dispersion correction (dft-d) for the 94 elements H-Pu, J. Chem. Phys. 132, 154104 (2010).  S. Grimme, S. Ehrlich, and L. Goerigk, Effect of the damping function in dispersion corrected density functional theory, J. Comp. Chem. 32, 1456 (2011).  S. Sakong, A. Groß, Methanol oxidation on Pt(111) from first-principles in heterogeneous and electro-catalysis, Electrocatal. 8, 577-586 (2017).
Members of the Tiger-Team: Institute for Theoretical Chemistry, and bwHPC-C5 Competence Center for Computational Chemistry, Ulm University