Characterization of copper clusters through the use of density functional theory reactivity descriptors

Abstract

In this paper we study nine neutral copper clusters through the theoretical characterization of their molecular structures, binding energy, electronic properties, and reactivity descriptors. Geometry optimization and vibrational analysis were performed using density functional theory calculations with a hybrid functional combined with effective core potentials. It is shown that reactivity descriptors combined with reactivity principles like the minimum polarizability and maximum hardness are operative for characterizing and rationalizing the electronic properties of copper clusters.

Optical absorption of small copper clusters in neon: Cun, (n = 1–9)

“…We find in agreement with previous DFT calculations 21,29,43,44,46,52,53 that the T d and D 2d geometries are close in energy. Cu 8 is a special case since in the jellium model it corresponds to a closed shell cluster.…”

“…Our DFT calculation, as well as recent calculations, 29,44,46,52,53 find that the ground state configuration is the three-dimensional D 5h structure, lying just below the C 3v structure. The low energy part of the spectrum, of s-s type, corresponds well with the calculation for the D 5h structure if we include a shift of ∼0.2 eV.…”

“…48 and 49) or DFT (Refs. 29,[43][44][45][46][50][51][52][53] schemes. All recent calculations agree that the planar D 2h geometry corresponds to the ground state structure.…”

“…Different DFT calculations were performed on this system, 29,43,44,46,[51][52][53] all of them including ours find the planar D 3h structure to be the most stable isomer, in close competition with the C 5v and C 2v three-dimensional structures. The analysis indicates, such as in the case of Cu 5 , that the low energy transitions, typically below 3 eV, are issued of the predominantly s-type HOMO Kohn-Sham orbital, while they are of of d-s type between 3 and 5 eV and of d-p type above 5 eV.…”

The CO2 dissociation mechanism on the small copper clusters—the influence of geometry

“…Table 1 shows the geometries and the energies expressed in eV with respect to the most stable cluster. The most stable of the Cu 6 clusters is the planar D 3h system (6A), as described by Jaque and Torro-Labbe [34]. The energy of the double-capped tetrahedron structure with C 2v symmetry (6C) is less stable by 0.24 eV.…”