Automated error control in divide-and-conquer self-consistent field calculations

In linear-scaling divide-and-conquer (DC) electronic structure calculations, a buffer region is used to control the error introduced by the DC approximation. In this study, an energy-based error estimation scheme is proposed for the DC self-consistent field method with a two-layer buffer region scheme. Based on this scheme, a procedure to automatically determine the appropriate buffer region in the DC method is proposed. It was confirmed that the present method works satisfactorily in calculations of water clusters and proteins, although its performance was insufficient for the calculation of a delocalized graphene system. © 2018 Wiley Periodicals, Inc.