First principles studies of magnesium oxide clusters by parallelized Tohoku University Mixed-Basis program TOMBO

We report the results of first principles calculations on neutral magnesium oxide clusters (MgO)nn ⩽ 13, using the parallelized all-electron Tohoku University Mixed-Basis Orbitals (TOMBO) program and local density approximation for the exchange-correlation energy. It uses both plane waves and atomic orbitals as the basis functions. Various isomers are studied for each size to find the lowest energy structures and to identify the magic clusters. Clusters with n = 4, 6, 9, and 12 are found to be magic in agreement with the available experimental data. The performance of the parallelized TOMBO is also studied by using different number of nodes on Hitachi SR8000 supercomputer.