Cobalt-doped gold clusters Aun
Co (n=1～7) are systematically investigated for the possible stable geometrical configurations and relative stabilities of the lowest-lying isomers using density-functional theory at B3LYP/LanL2DZ level. Several low-lying isomers were deter-mined, and many of them are in electronic configurations with a high spin multiplicity. The results indicate that the ground-state Aun
Co (n=1～7) clusters adopt a planar structure except for n=7. The stability trend of the Aun
Co (n=1～7) clusters shows that the Au2
Co clusters are magic cluster with high stability.