Photoelectron imaging and theoretical investigation of bimetallic Bi1–2Ga0–2− and Pb1–4− cluster anions

We present the results of photoelectron velocity-map imaging experiments for the photodetachment of small negatively charged BimGan (m=1–2, n=0–2), and Pbn (n=1–4) clusters at 527 nm. The photoelectron images reveal new features along with their angular distributions in the photoelectron spectra of these clusters. We report the vertical detachment energies of the observed multiple electronic bands and their respective anisotropy parameters for the BimGan and Pbn clusters derived from the photoelectron images. Experiments on the BiGan clusters reveal that the electron affinity increases with the number of Ga atoms from n=0 to 2. The BiGa2− cluster is found to be stable, both because of its even electron number and the high electron affinity of BiGa2. The measured photoelectron angular distributions of the BimGan and Pbn clusters are dependent on both the orbital symmetry and electron kinetic energies. Density-functional theory calculations employing the generalized gradient approximation for the exchange-c...