Abstract: First-principle calculations were performed on the geometric structure and adsorption properties of CO monolayer on Cu(001) surface by using USPP and FLAPWmethods. Relaxed geometry structure suggested that top was the most stable site. The distance between C and Cu atoms was about 0.1868 nm on top site, compared with 0.1975 nm on bridge sites and 0.2231 nm on hollow sites. The bond length of CO molecules on top, bridge and hollow sites were estimated to be 0.1154, 0.1165 and 0.1175 nm, respectively. From the structure of adsorbed surface, it was found that the bond length of COwas enlarged by the nearest copper atoms. PDOS (partial orbital of density of state) of COshowed that the interaction between adsorbent and adsorbate was mainly induced by the hybridization of molecule 5σ orbital and copper 3d orbital. The hybridization was mainly induced by the symmetry of orbital and sites. The result of orbital charge indicated that the s orbital charge of carbons reduced and the p orbital charge of carbons increased, when CO molecules were adsorbed on the top sites. At last, the work functions for three adsorbed surfaces were investigated, which were calculated to be 5.51 eV on top, 6.00 eV on bridge, and 6.23 eV on hollow, in contrast to 4.57 eV in clean surface. The work function and DOS indicated that CO layer was insulating.

Key words: Cu(001), CO monolayer, Atomic geometry, Density of state