Chemisorption of OCN on Cu (100) surface: A density functional study

The chemisorption of cyanato radial (OCN) on Cu (100) surface is studied by using density functional theory (DFT) and the cluster model method. Cu ₁₄ cluster is used to simulate the surface. Vertical bonding geometries with the nitrogen or oxygen atom down, and a parallel bonding geometry are considered, respectively. The present calculations show that cyanato-N species absorbed on the surface is more favorable than the other configurations. It indicates that OCN species is linearly bonded to the Cu (100) surface via the nitrogen atom, and is in good agreement with the experimental result. The cyanato-N species at the bridge site is most stable. For cyanato-N, the calculated symmetric and asymmetric OCN stretch frequencies are all blue-shifted compared with the calculated gaseous values, which is consistent with the experiment result. The charge transfer from the surface to OCN causes a work function increase on the surface. Bonding of OCN to the metal surface is largely ionic.