Phys. Chem. Chem. Phys., 23, 14830-14835 (2021)
Computing gold cluster energies with density functional theory: the importance of correlation
Piero Ferrari a and Klavs Hansen*, b
a Department of Physics and Astronomy, Quantum Solid State Physics, KU Leuven, 3001 Leuven, Belgium.
b Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
Energies calculated with density functional theory depend critically on the choice of the exchange–correlation functional. In this work, we use measured dissociation energies of Aun+ (n = 5–17) clusters as benchmark data to test two very different functionals for calculating total energies in these clusters; the simpler (and fast) PBE and the evolved (and expensive) B2PLYP double-hybrid functionals. PBE consistently gives poor agreement with the experimental results. In contrast, the B2PLYP functional, which implicitly includes electron correlation by performing a perturbative second-order correction, significantly improves the agreement of the calculations, at the cost of much more demanding computations. The better performance of the double-hybrid functional is ascribed to the longer range of the interatomic potential.