Carbon monoxide adsorption on small Si clusters: a full-potential linear-muffin-tin-orbital molecular-dynamics study

Using the full-potential linear-muffin-tin-orbital method, we have performed molecular-dynamics simulations for carbon monoxide (CO) adsorption on Si 2-7 clusters. The calculations show that the carbon monoxide can be adsorbed tightly on an active site of each small silicon cluster. Their adsorption energies decrease successively and rapidly as the atom number of the silicon clusters increases. Besides the active sites, there are some other sites on which the CO molecule can be very weakly bound as a molecule. When the CO molecule is adsorbed on the active sites, the CO bond length and the structures of the Si clusters will change significantly. Otherwise, the CO molecule remains almost unchanged, and the changes in the structures of the Si clusters resulting from the carbon monoxide molecular adsorption are much less than those caused by H 2 O, NH 3 , and C 2 H 4 adsorptions.