Carbonmonoxide adsorption on small Si clusters: a full-potentiallinear-muffin-tin-orbital molecular-dynamics study

Abstract

Using the full-potential linear-muffin-tin-orbital method, we haveperformed molecular-dynamics simulations for carbon monoxide(CO) adsorption on Si2-7 clusters. The calculations show thatthe carbon monoxide can be adsorbed tightly on an active site of eachsmall silicon cluster. Their adsorption energies decreasesuccessively and rapidly as the atom number of the silicon clustersincreases. Besides the active sites, there are some other sites onwhich the CO molecule can be very weakly bound as a molecule. Whenthe CO molecule is adsorbed on the active sites, the CO bond lengthand the structures of the Si clusters will change significantly.Otherwise, the CO molecule remains almost unchanged, and the changesin the structures of the Si clusters resulting from the carbon monoxidemolecular adsorption are much less than those caused by H2O, NH3, andC2H4 adsorptions.