Interaction between O2 and neutral/charged Aun (n = 1–3) clusters: A comparative study between density-functional theory and coupled cluster calculations

We have performed a benchmark study of molecular O2 binding on Aun (n = 1–3) clusters using density-functional theory and high-level coupled-cluster calculations. Based on the computed structural and energetic properties of O2 binding on anionic, cationic, and neutral Aun (n = 1–3), we find that the hybrid functionals (HSE06, PBE0, and B3LYP) and the M06 functional with large basis sets give much more reasonable binding energy of O2 and O–O bond length compared to GGA functionals (PBE and TPSS). In particular, the HSE06 functional gives the best agreement with CCSD(T)//MP2 method in O2 binding energy on neutral Au3.