Our ab initio calculations of $\mathrm{CO}$ adsorption on several low and high Miller index surfaces of Cu show that the adsorption energy increases as the coordination of the adsorption site decreases from 9 to 6, in qualitative agreement with experimental observations. On each surface the adsorption energy is also found to decrease with increase in coverage, although the decrement is not uniform. Calculated vibrational properties show an increase in the frequency of the metal-C mode with decrease in coordination, but no such effect is found for the frequency of the $\mathrm{CO}$ stretch mode. Examination of the surface electronic structure shows $\mathrm{CO}$ adsorption to have a strong effect on the local density of state of the substrate atoms. We also report calculated energetics of $\mathrm{CO}$ diffusion on $\mathrm{Cu}\left(111\right)$ and $\mathrm{Cu}\left(211\right)$.

• Received 12 December 2005

DOI:https://doi.org/10.1103/PhysRevB.74.155439