Probing the structural and electronic properties of cationic rubidium–gold clusters: [Au_nRb]⁺ (n = 1–10)

ABSTRACT

Density functional theory has been applied to study the geometric structures, relative stabilities, and electronic properties of cationic [Au_nRb]⁺ and Au_{n + 1}⁺ (n = 1–10) clusters. For the lowest energy structures of [Au_nRb]⁺ clusters, the planar to three-dimensional transformation is found to occur at cluster size n = 4 and the Rb atoms prefer being located at the most highly coordinated position. The trends of the averaged atomic binding energies, fragmentation energies, second-order difference of energies, and energy gaps show pronounced even–odd alternations. It indicated that the clusters containing odd number of atoms maintain greater stability than the clusters in the vicinity. In particular, the [Au₆Rb]⁺ clusters are the most stable isomer for [Au_nRb]⁺ clusters in the region of n = 1–10. The charges in [Au_nRb]⁺ clusters transfer from the Rb atoms to Au_n host. Density of states revealed that the Au-5d, Au-5p, and Rb-4p orbitals hardly participated in bonding. In addition, it is found that the most favourable channel of the [Au_nRb]⁺ clusters is Rb⁺ cation ejection. The electronic localisation function (ELF) analysis of the [Au_nRb]⁺ clusters shown that strong interactions are not revealed in this study.

GRAPHICAL ABSTRACT

KEYWORDS:

• Geometric structure
• density functional theory
• electronic property

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Natural Science Foundation of China [grant number 11404008]; Natural Science Basic Research Plan in Shaanxi Province of China [grant number 2013JQ1007]; Scientific Research Plan Projects of Education Department of Shaanxi province of China [grant number 14JK1044]; Baoji University of Arts and Sciences Key Research [grant number ZK12048]; Education Department of Sichuan province [grant number 15ZB0207]; Sichuan University of Science and Engineering [grant number 2015RC41], [grant number 2015RC44].