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.
E-mail: piero.ferrari@kuleuven.be
b Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, 92 Weijin Road, Tianjin 300072, China.
E-mail: klavshansen@tju.edu.cn
Abstract
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.
