Empirical potential study of the chemisorption of C2H2 and CH3 on the β-SiC(001) surface

We have used an extended form of the Brenner empirical hydrocarbon potential to study the reconstructions of the clean beta-SiC(001) surface. and the chemisorption of C2H2 and CH3 molecules onto the silicon terminated (2 x 1) surface. For reference, chemisorption energies and minimum-energy geometries have also been obtained from Becke3LYP HF DFT cluster calculations, Optimal C2H2 chemisorption at low coverage was found to occur with the adsorbate molecule situated above the cave site. with the carbon-carbon bond oriented in the [110] direction parallel to the dimer rows, At 1 monolayer coverage this wits also the preferred structure, with the adsorbate molecules positioned in a staggered c(2 x 2) arrangement. Optimal CH3 chemisorption was found to occur with the CH3 radicals bonding directly to the surface dangling bonds. (C) 1998 Elsevier Science B.V.