Perovskite models of supercell (2×2×3) were set up for PbMg1/3Nb2/3O3 (PMN). Ab initio computations were performed for understanding the configuration distribution of PMN. The energy difference between the lowest and the highest in PMN supercell models is about 0.74 a.u. (1940 kJ). Pb2+ lattice distortion may be the main factor in the PMN system’s deformation. Less MgO6 is favorable for Ti’s substitution of Nb. The configuration distribution and local deformation in lattice is dependent on the process of PMNT.

Key words: PMN; PMNT; Ab initio; Local structure; deformation