Energy density analysis of cluster size dependence of surface-molecule interactions: H₂, C₂H₂, C₂H ₄, and CO adsorption onto Si(100)-(2×1) surface

The adsorption of H₂, C₂H₂, C ₂H₄ and CO molecule onto a Si(100)-(2×1) surface was studied. The surface-molecule interactions for different cluster size were examined by the energy density analysis (EDA). It was found that at least a Si₂₁H₂₀ cluster was necessary to treat the surface-molecule interaction with chemical accuracy in the cases of H ₂, C₂H₂, C₂H₄ and CO absorption onto the Si(100)-(2×1) surface. The applicability and reproducibility of the EDA technique in cis, trans-enol isomerization, proton transfer reactions and internal methyl rotations was also reported.