We have developed the chemical reaction simulation program for large systems named DC-DFTB-K [1]. The DC-DFTB-K program has three pillars: the linear-scaling divide-and-conquer (DC) technique, the density-functional based tight-binding (DFTB) method, and massive parallel computation. High efficiency of the program has been confirmed from the numerical applications. For example, the quantum mechanical energy calculations of 500,000 water molecules (1.5 million atoms) can be accomplished in ~40 seconds when using 128,000 CPU cores of K computer. The program was applied to several chemical reactions such as proton diffusion in water [2] and CO<sub>2</sub> chemical absorption process [3]. The developed technique is promising to fill a gap between classical and quantum mechanical molecular dynamics (MD) simulations.

Chemical reaction simulations treated by linear-scaling Divide-and-Conquer Type Density-Functional Based Tight-Binding Molecular Dynamics (DC-DFTB-MD) method

253rd National Meeting (2017)

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