In this work constant energy molecular dynamics simulations are achieved for investigating sputtering process of Ar + Ni(1 0 0) collision system. The Ni crystal is imitated by an embedded-atom potential, whereas the interaction between the projectile and the surface is modeled by re-parameterized ZBL potential. Seven hundred eighty-four Ar atoms carrying 20-50 eV are sent towards a Ni(1 0 0) surface at normal incidence. Each projectile meets with different initial coordinates (phase) of the nickel atoms because of thermal vibrations in the slab. Effects of the different initial phases of the surface are compared with the available theoretical and experimental data. (C) 2009 Elsevier B.V. All rights reserved.