Ab initio density functional theory (DFT) methods have been employed to investigate the electronic structure of atomic clusters representing the T-4 and H-3 adatom bonding configurations of the Si(111)root 3x root 3R30 degrees -Si reconstructed surface. The nature of the bending between the Si adatom and its nearest neighbor atoms on the Si(111) surface is discussed by analyzing the density of states (DOS), projected DOS, charge distributions and the molecular orbital overlap population (MOOP). The results provide an explanation for the difference in stability between the T-4 and H-3 configurations.