Density-Functional Tight-Binding Combined with the Fragment Molecular Orbital Method

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• 作者：Yoshio Nishimoto ; Dmitri G. Fedorov ; Stephan Irle
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：10
• 期：11
• 页码：4801-4812
• 全文大小：528K
• ISSN：1549-9626

文摘

We developed the energy and its gradient for the self-consistent-charge density-functional tight-binding (DFTB) method, combined with the fragment molecular orbital (FMO) approach, FMO-DFTB, including an optional a posteriori treatment for dispersion interaction, and evaluated its accuracy as well as computational efficiency for a set of representative systems: polypeptides, a DNA segment, and a small protein. The error in the total energy of FMO-DFTB versus full SCC-DFTB was below 1 kcal/mol for the polyalanine system consisting of about 2000 atoms partitioned into fragments containing 2 residues, and the optimized structures had root-mean-square deviations below 0.1 脜. The scaling of FMO-DFTB with the system size N is only marginally larger than linear [O(N^1.2) in the worst case]. A parallelization efficiency of 94% was achieved using 128 CPU cores, and we demonstrate the applicability of FMO-DFTB for systems containing more than one million atoms by performing a geometry optimization of a fullerite cluster.