With the exception of the (201) surface, all higher order surfaces had cleavage energy exceed 2 J m -2 . However, once they were relaxed, the surface energies were about 1 J m -2 lower than in energy, indicating a large relaxation had occurred. Referring back to the discussion earlier in Section 3.1, all the surfaces that saw a drastic reduction in excess energy were the ones where the surface TiO 3 S units were able to contract into a more tetrahedral shape.