The influence of translational kinetic energy of incident O-2 molecules for the passive oxidation of the partially oxidized Si(001) surface has been studied by photoemission spectroscopy. The incident energy of O-2 molecules was controlled up to 3 eV by a supersonic molecular beam technique. Two incident energy thresholds (1.0 and 2.6 eV) were found out in accordance with the first-principle calculations. Si 2p and O 1s photoemission spectra measured at representative incident energies showed the incident energy induced oxidation at the backbonds of the dimer and the second layer (subsurface) Si atoms. Moreover, the difference of oxygen chemical bonds was found out to be as the low and the high binding energy components in the O 1s photoemission spectra, They were assigned to bridge sites oxygen and dangling bond sites oxygen, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.