Benchmarking density functional theory methods for modelling cationic metal–argon complexes

Abstract

Noble gas chemistry is fascinating because noble gases can make formal chemical bonds with metal ions, despite their closed electronic configuration. Argon-metal ion complexes are particularly interesting since their bonding is halfway between dispersion and covalent interactions. Although many metal ion-noble gas complexes have been synthesized, there are still disagreeing theoretical descriptions about their bonding, which is not yet fully understood. Accurate experimental data is important as solid reference for theoretical methodologies, but such data is currently scarce for complexes of metal ion with noble gas atoms. We measured infrared spectra of MArn + (n = 3-5; M = Au, Ag, Pd) complexes and use these spectra as benchmark data for different theory levels within the density functional theory formalism. Several basis sets, exchange-correlation functionals, and the inclusion of dispersion corrections were considered. The agreement between the measured spectra and the calculations strongly depends on the applied level of theory. Functionals of a higher level of complexity do not consistently provide a better agreement with the experiment; this is particularly the case for the B3LYP hybrid functional that performs worse than the PBE GGA functional. On the other hand, the inclusion of dispersion corrections and the use of a large basis sets are crucial for a good description of the interaction between M + and Arn.

Argon Adsorption on Cationic Gold Clusters Aun+ (n ≤ 20)

“…Dispersion forces were accounted for via the D3BJ dispersion-correction [ 35 ]. This level of theory was shown to be accurate and computationally efficient for describing the interactions in Au + -Ar m ( m ≤ 4) [ 21 ]. The geometries of the bare Au n + ( n = 3–20) clusters were adopted from previous works.…”

“…One consequence of the relativistic effects in Au is an enhanced electron affinity [ 20 ], if compared, for instance, with Ag and Cu. The high electron affinity was shown to favor electron transfer from the Ng atom to Au in the AuNg + dimer and therefore the formation of a relatively strong bond [ 21 ].…”

Bonding Nature between Noble Gases and Small Gold Clusters

“…This level of theory was selected based on two previous studies, where a correct description of Ng interactions with gold clusters was shown. 21,29 While for Au 2 Ng 4 + and + , a second stable configuration of the Ng atoms is shown in the Supporting Information. Importantly, this additional configuration also has three Ng atoms adsorbed on an atop coordination.…”

The size-dependent influence of palladium doping on the structures of cationic gold clusters

“…This functional has also been used to calculate properties of Pd and Ag doped Au clusters, 25,31,32,44,45 and correctly predicted the vibrational modes of Au + ·Ar m and Pd + ·Ar m complexes. 46 An extensive isomer global search of PdAu n −1 + isomers was performed in ref. 31 .…”