Adsorption properties of 4-bromostyrene (Br-Sty) on the Si(001)-(1 x 2) surface are investigated by ab initio calculation based on density functional theory (DFT). For the adsorption of Br-Sty molecule on the Si (001)-(1 x 2) surface, we have assumed two possible cases within: (i) binding on the partially H-terminated surface and (ii) binding on the clean surface. For the first case, we have estimated two different binding sides: (i) Bromine-terminated bindings and (ii) Carbon-terminated binding. The adsorption energies of Br-terminated and C-terminated binding were found as 0.36 eV and 3.76 eV, respectively. In the same manner, we have also assumed two possible binding sides for the clean surface: (i) Br-terminated binding and (ii) ring-shaped binding. We have found adsorption energies for Br-terminated and ring-shaped binding as 0.14 eV and 1.10 eV on the clean surface, respectively. Moreover, the nudged elastic band method (NEB) was used to reveal the adsorption pathway of these binding models. These results serve to understand the possibility of the adsorption of Br-Sty molecules onto different kind of silicon surfaces into different reaction conditions. (C) 2011 Elsevier B.V. All rights reserved.