Photoelectron Spectroscopy and Theoretical Study of Di-Copper–Boron Clusters: Cu<sub>2</sub>B<sub>3</sub><sup>–</sup> and Cu<sub>2</sub>B<sub>4</sub><sup>–</sup>
Anton S. Pozdeev, Weijia Chen, Hyun Wook Choi, Maksim Kulichenko, Dao-Fu Yuan, Alexander I. Boldyrev, Lai‐Sheng Wang
Abstract
Copper has been found to be able to mediate the formation of bilayer borophenes. Copper–boron binary clusters are ideal model systems to probe the copper–boron interactions, which are essential to understand the growth mechanisms of borophenes on copper substrates. Here, we report a joint photoelectron spectroscopy and theoretical study on two di-copper-doped boron clusters: Cu 2 B 3 – and Cu 2 B 4 – . Well-resolved photoelectron spectra are obtained, revealing the presence of a low-lying isomer in both cases. Theoretical calculations show that the global minimum of Cu 2 B 3 – ( C 2 v, 1 A 1 ) contains a doubly aromatic B 3 – unit weakly interacting with a Cu 2 dimer, while the low-lying isomer ( C 2 v, 1 A 1 ) consists of a B 3 triangle with the two Cu atoms covalently bonded to two B atoms at two vertexes. The global minimum of Cu 2 B 4 – ( D 2 h, 2 A g ) is found to consist of a rhombus B 4 unit covalently bonded to the two Cu atoms at two opposite vertexes, whereas in the low-lying isomer ( C s, 2 A ′), one of the two Cu atoms is bonded to two B atoms.