Structural stability and energetics of gold clusters, Au, (n = 3-555), have been investigated by molecular-dynamics simulations. An empirical model potential energy function has been used in the simulations. Stable structures of the microclusters for n = 3-13 have been determined by molecular-dynamics simulation. It has been found that gold microclusters prefer to form three-dimensional compact structures. Molecular-dynamics simulations have also been performed for spherical gold clusters generated from FCC crystal structure with sizes n = 13-555. it has been found that the gold nanoparticles are more stable in the FCC form. (C) 2000 Elsevier Science B.V. All rights reserved.