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O: Fachverband Oberflächenphysik
O 83: Frontiers of Electronic Structure Theory: Focus on Artificial Intelligence Applied to Real Materials 4
O 83.4: Talk
Friday, September 9, 2022, 11:15–11:30, S054
Ab initio random structure search of organic molecules at substrates — •Dmitrii Maksimov1,2 and Mariana Rossi1,2 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
Finding stable structures of molecular adsorbates (in isolation or forming layers) from calculations is challenging, exacerbated when the adsorbates are flexible. To make matters more complicated, in these situations, it is often difficult to find good and cheap potentials of such complex interfaces that allow a thorough and reliable global search of the structural space. To make this problem tractable with ab initio potentials, we present a random global geometry optimization package that can explicitly take into account the internal degrees of freedom of molecules, their position and orientation with respect to fixed surroundings, as well as periodic boundary conditions [1]. Electronic structure calculations and local geometry optimizations are performed through a connection to the ASE software [2], making it possible to interface this algorithm with various codes. To increase the efficiency of geometry optimizations, we introduce a framework to construct initial approximate Hessians for BFGS algorithms that are specially tailored to accelerate the relaxation of van der Waals bonded structures and handle large structural changes. We showcase the algorithm for the adsorption of di-L-alanine at Cu(110). [1] https://github.com/sabia-group/gensec [2] Larsen et. al., J. Phys.: Condens. Matter 29, 273002 (2017).