DFT and QTAIM studies on structure and stability of beryllium doped gold clusters

Impurity-doped clusters particularly the gold doped bimetallic clusters have received considerable attention in the last few years. The doped atoms can considerably alter the geometrical and electronic properties as well as the stability of gold clusters. Density functional theory (DFT) with B3LYP functional have been applied to study the geometrical structures and relative stabilities of small bimetallic neutral, cationic and anionic AunBe (n = 1–6) and AunBe2 (n = 1–5) clusters. For AunBe2 clusters, we obtained only planar structure whereas AunBe clusters show both planar and three dimensional structures. The relative stabilities of the clusters are compared on the basis of average binding energies, fragmentation energies and second order difference of energies. The fragmentation energies and second order difference of energies of all the three types of clusters shows the even–odd alternation phenomenon. The nature of bonding interaction is also investigated by using Bader’s quantum theory of atoms in molecules (QTAIM). Based on QTAIM results, we can suggest that the beryllium doped clusters are more stable than the pure gold clusters due to strong covalent interaction between the gold and beryllium metal centres.