Structural and electronic properties of a carbon monoxide monolayer

Abstract A new ab initio pseudofunction method based on solid state theoretical approaches has been developed which is designed to accurately calculate the electronic properties and total energy of molecules on surfaces and other interfacial systems. This method is used here to investigate critical bonding information of an isolated carbon monoxide layer in the C(2×2)-Ni(001) configuration characteristic of chemisorption on a Ni(001) surface. Results for a two-dimensional array of CO molecules give an equilibrium bond length of 1.138 A versus 1.128 A (experimental), derivative of dipole moment of 3.16 D/A versus 3.14 D/A (experimental), and a vibrational frequency of 2157 cm -1 versus 2170 cm -1 (experimental), where the experimental values correspond to free CO. Thus, the CO bond length and derivative of dipole moment and vibrational frequency are practically unaltered from that of free CO. We found, however, the dipole moment, 1.0 Debyes, and the 1π-4σ level separation, ∼2.4 eV, are substantially changed due to COCO coupling.