Abstract:
The interaction between a low energy C
20 molecule and a reconstructed silicon (100)-(2×1) surface is simulated with a hybrid potential, which is a combination of the Tersoff potential and the repulsive KrC potential. After impacting of the silicon substrate, the C
20 cluster is found to move along 〈110〉 direction as a rigid sphere. The collective motion of the C
20 molecule can be explained by the anisotropic force field between the dimerized silicon surface and the C
20 molecule. Different impact energies lead to different closet interaction distances between the C
20 molecule and the silicon surface, which generate different distributions of the lateral force field. Changes in the force field lead to different kinetic behavior of the C
20 along the 〈110〉 direction. Finally, the C
20 comes to rest on the surface when its kinetic energy is consumed up. In the trough or on the top of a dimer are the two energy favored adsorption sites of the C
20 on the silicon surface. The formation of C-Si bonds is an indication that strong bindings between the C
20 and the silicon surface exist. These results are consistent with experimental findings of C
20 molecules adsorbed on a reconstructed silicon surface.