[en] We proposed a pair of coupled continuum equations to generate a rough surface which models molecular beam epitaxy. In these equations we argue that the atoms from a mound point of a rough surface can be dislodged very easily than that from a groove. In this study we use the Recursion method coupled with the TB-LMTO method to get the density of states of different points on the rough surface. Then we use Burke orbital peeling method to determine the energy required to knock-off atoms on the different points of rough surface. (author)