With modified analytical embedded atom method (MAEAM), the energy of (0 1 1) twist grain boundary (GB) has been calculated for three noble metals Cu, Ag and Au. The results show that the unrelaxed energy keeps almost constant with twist angle 0 except several cusps at low Sigma boundaries. The GB energies drop significantly after expansion perpendicular to the boundary. In-boundary translation results in a periodic energy variation and the rectangular period is 1/Sigma of their own CSL smallest unit cell. Three specific positions, the corners or centre of the periodic rectangle, or the midpoints of the sides, are preferable in GB translation. (c) 2005 Elsevier B.V. All rights reserved.