Combining 2d-Periodic Quantum Chemistry with Molecular Force Fields: A Novel QM/MM Procedure for the Treatment of Solid-State Surfaces and Interfaces

Abstract

The feasibility of a novel approach for the hybrid quantum mechanical/molecular mechanical (QM/MM) treatment of solid-state surfaces without the requirement of artificially keeping atoms at fixed positions is explored. In order to avoid potential artifacts of the QM/MM transition near the surface, a 2d-periodic QM treatment of the system is employed. Thus, the only QM/MM interface between atoms of the solid is along the non-periodic z-dimension. It is shown for the metal oxide and metal systems MgO(100) and Be(0001) that a properly adjusted embedding potential supplemented by adequate non-Coulombic potentials (if required) enables the application of the QM/MM framework in all-atom structure optimization and molecular dynamics (MD) simulation. The commonly employed constraint to keep at least some of the embedding atoms at fixed position is not required. Two exemplary applications of H2O on MgO(100) and H2 on Be(0001) demonstrate the applicability of the framework in exemplary MD simulation studies.

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

“…The employed 3d-periodic DFTB/MM framework was implemented in our previously developed QM/MM MD simulation program [60][61][62] interfaced to the DFTB+ package. Each atom in the cell was considered as irreducible as required by the molecular dynamics framework.…”

“…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.…”

Multi-scale approach to first-principles electron transport beyond 100 nm

“…A promising solution which is rapidly growing along many lines of research is to perform hybrid multi-scale simulations. [1,[29][30][31][32][33][34][35][36][37] In this context an interesting approach is to treat crucial parts of a relatively large device using full quantum-chemical detail, while reducing the number of degrees of freedom to the bare essentials elsewhere. [1, 29-33, 38, 39] A very popular example, coming from a biomolecular context, is the quantum mechanics/molecular mechanics (QM/MM) technique, [40] which has also been generalized to study solid-state surfaces and interfaces.…”

Editorial: Quantum Mechanical/Molecular Mechanical Approaches for the Investigation of Chemical Systems – Recent Developments and Advanced Applications

“…Today, four decades after these influential developments, QM/MM methods are regarded as one of the most influential approaches for the description of challenging chemical phenomena. Initially conceived in the framework of biomolecular simulations (Friesner and Guallar, 2005 ; Hu and Yang, 2009 ; van der Kamp and Mulholland, 2013 ; de Visser et al, 2014 ; Cui, 2016 ; Lu et al, 2016 ; Quesne et al, 2016 ), the range of QM/MM methods has been substantially extended to include other areas accessing inter alia solid-state chemistry and material science (Gonis and Garland, 1977 ; Krüger and Rösch, 1994 ; Stefanovich and Truong, 1996 ; Jacob et al, 2001 ; Herschend et al, 2004 ; Keal et al, 2011 ; Bjornsson and Bühl, 2012 ; Golze et al, 2013 , 2015 ; Hofer and Tirler, 2015 ) and solution chemistry (Staib and Borgis, 1995 ; Tuñón et al, 1995 , 1996 ; Gao, 1996 ; Hofer et al, 2010 , 2011 , 2012 ; Weiss and Hofer, 2012 ; Hofer, 2014 ) as well. These QM/MM studies have given insight into how Nature works, and, for instance, explain regio- and stereochemical selectivities during substrate activation (Faponle et al, 2016 , 2017 ; Timmins et al, 2017 ).…”