Fast calculation approach to semi-empirical molecular orbital method using real space division method

The authors have developed a new approach for large-scale systems including over 100,000 atoms to obtain physical strength from the viewpoint of atom–atom bonding energy. Combining the semi-empirical molecular orbital method with real space division method makes it possible to estimate structural parameters, electronic structures and bonding energy for various large systems. With this method, various quantum physical properties can be obtained quickly using the semi-empirical molecular orbital method, while adopting real space division improves the computational efficiency of parallelization. In this study, the authors applied this method to SiH4 molecule and crystalline silica system, and carried out bond order and bonding energy analyses. In this analysis, the developed method offered almost the same analytical accuracy as the first principle method, while its calculation speed was much faster than that of the latter. The developed method was also suitable for parallel computing.