Exploring structures, electronic and reactivity properties of Au6Hn (n = 1–12) clusters: A DFT approach

Abstract

Density functional calculations at the PBE/DNP level have been carried out to investigate the structures, electronic and reactivity properties of Au6Hn (n=1–12) clusters. Adsorption of hydrogen atoms stabilizes the Au6 cluster indicated by the high binding energies. The adsorption of H atoms till Au6H6 retains the planar triangular structure of Au6. However, the triangular structure is distorted on further addition of H atoms till Au6H9. In clusters Au6H10, Au6H11 and Au6H12, though the triangular structure is restored but the structures are non-planar. The averaged Hirshfeld atomic charges indicate the H atoms to be negatively charged in all the clusters. Odd–even alternation in HOMO–LUMO gap, chemical hardness, vertical ionization potential, adiabatic ionization potential and binding energy is observed with the clusters having even number of H atoms possessing higher values and are observed to be more stable than their congeners with odd number of H atoms. DFT based reactivity descriptors indicate that in Au6, the Au atoms forming the vertices of the outer triangle have higher relative electrophilicity value while those forming the vertices of the inner triangle have higher relative nucleophilicity value. However, in Au6H6, two nearby Au sites forming the vertices of the inner and outer triangle have the highest relative electrophilicity and relative nucleophilicity values. In Au6H12, these are located in the inner triangle.