Abstract: The interaction of two NO molecules and NO dimers with Cu2 has been studied at B3LYP/Lanl2DZ level. The results show that the NO molecules and dimers can be stably adsorbed on the adjacent Cu atoms on the copper surface. However, the structure of NO adsorbed on Cu atom with N-down ward is more stable than any other structure in the NO co-adsorption models, and the NO atop adsorption is less stable than the other. On the other hand, the N－N bond is strengthened, while the N-O bond is weakened in the NO dimer adsorption models. It indicates that the formation of NO dimer is favorable to the NO direct decomposition on the copper surface. The Mülliken population analysis shows that the average charge on Cu is 0.66 e, when the singlet state dimer interacts with the copper. It suggests that the bond between the singlet state dimer and the Cu atom is more ionic, and that the N-O bond is more reactive in singlet state dimer. The calculation results reasonably indicate that NO can be directly decomposed via the dimer configurations on the copper surface.

Key words: Cu₂, NO, Dimer, Adsorption, Density functional theory(DFT)