Energy window effect in chemisorption of C-36 on diamond (001)-(2 x 1) surface

In this paper, the collision of a C-36. with D-6h symmetry, on diamond (0 0 1)-(2 x 1) surface was investigated using molecular dynamics (MD) simulation based on the semi-empirical Brenner potential. The incident kinetic energy of the C-36 ranges from 20 to 150 eV per cluster. The collision dynamics was investigated as a function of impact energy Ei,. The C,h cluster was first impacted towards the center of two dimers with a fixed orientation. It was found that when Ei, was lower than 30 eV, C-36 bounces off the surface without breaking up. Increasing E-in to 30-45 eV, bonds were formed between C36 and surface dimer atoms, and the adsorbed C-36 retained its original free-cluster structure. Around 50-60 eV, the C-36 rebounded from the surface with cage defects. Above 70 eV. fragmentation both in the cluster and on the surface was observed. Our simulation supported the experimental findings that during low-energy cluster beam deposition small fullerenes could keep their original structure after adsorption (i.e. the memory effect), if E-in is within a certain range. Furthermore, we found that the energy threshold for chemisorption is sensitive to the orientation of the incident C36 and its impact position on the asymmetric surface. (C) 2001 Elsevier Science B.V. All rights reserved