Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 97: Nanostructure at Surfaces: Structures and Properties
O 97.5: Vortrag
Freitag, 20. März 2015, 11:30–11:45, MA 005
Efficient conformational sampling of complex adsorbates: Basin Hopping in curvilinear coordinates — Konstantin Krautgasser1, •Chiara Panosetti1, Dennis Palagin2, Karsten Reuter1, and Reinhard Maurer3 — 1Technische Universität München, Germany — 2University of Oxford, GB — 3Yale University, USA
Continuous computational and methodological advances provide first-principles access to ever larger and more complex adsorbate molecules. The vastly increasing configurational spaces of such molecules nevertheless pose an enormous challenge. Local geometry optimizations of a few chemically motivated adsorption modes are inadequate to sample these spaces and need to be replaced by rigorous global optimization techniques. In those, a crucial role is played by the choice of coordinates representing geometries and trial moves. When aiming for sampling in chemically motivated subspaces the most popular, but physically blind choice of Cartesians is often inefficient. Rather than e.g. testing for adsorption modes of the intact adsorbate, Cartesian trial moves may quickly lead to dissociated structures. We address this by presenting a Basin Hopping (BH) scheme employing Delocalized Internal Coordinates (DICs) suitable for covalently bound systems. In the application to two rather diverse systems we indeed find that such DIC trial moves significantly reduce the sampling efficiency: Retinoic Acid on Au(111) and Si16H16 clusters in gas-phase and on Si(001).