Photoelectron spectroscopy and density functional theory study of Bi2Aln− (n = 1–4) clusters

The Bi2Aln− (n = 1–4) clusters were investigated by anion photoelectron spectroscopy and density functional theory calculations. By photoelectron spectroscopy the vertical detachment energies of Bi2Aln− (n = 1–4) were determined to be 2.12 ± 0.08, 2.32 ± 0.08, 2.66 ± 0.08, and 2.15 ± 0.08 eV, respectively. The structures of Bi2Aln− (n = 1–4) were determined by comparison of photoelectron experiments and calculations. It is found that Bi2Aln− (n = 1–4) anions all have a Bi2 unit inside their structures, in which the BiBi bond lengths are in the range of 2.81–3.08 Å. The natural population analysis shows that the negative charges mainly localized on the Bi2 unit inside the most probable structures.