Study of NO and CO dissociation on the (100) Cu surface using density functional theory and the topological analysis of the electronic density and its Laplacian

Abstract:

Molecular orbital ab initio Hartree-Fock, post-Hartree-Fock at the MP2 and QCISD levels, and density functional theory calculations of the dipole moment, the topology of the electronic density, ρ(r), and its Laplacian, ∇2ρ(r), for CO and NO molecules are reported. The results obtained confirm that density functional methods provide remarkably good electronic properties and a good description of the topology of ρ(r) and ∇2ρ(r). The Becke exchange functional with the correlation functional of Lee, Yang, and Parr was used to calculate the electronic density of the (100) Cu surface. Topological analysis of ρ(r) shows that the crystal graph corresponds to square pyramids between the atoms of the top of the surface and the atoms of the second layer. The topological analysis of -∇2ρ shows that the atomic graph of the Cu surface exhibits one (3,-3) local charge concentration surrounded by four (3,+1) local charge depletion points. Additionally, there is a (3,+3) local depletion in the midpoint between each of four contiguous Cu atoms corresponding to the active site for the adsorption of the (3,-3) local charge concentration on the C atom of the CO or the N atom of the NO molecule. The larger value of the -∇2ρ at the nonbonded charge concentration on the atoms and the geometrical configuration of these critical points favor the interaction of the NO over the CO molecule with the (100) Cu surface. This result is in accord with the known reaction barriers for these molecules.

Año de publicación:

1996

Keywords:

• density functional theory
• (100) Cu surface
• Carbon monoxide
• Nitrogen monoxide
• Molecular graph
• Laplacian of the electronic density
• Atomic graph

Fuente:

scopus