Probing the Geometric and Electronic Structures of the Monogadolinium Oxide GdOn-1/0 (n=1-4) Clusters

The existence of abundant 4f electrons significantly increases the complexity and difficulty in precisely determining the geometric and electronic structures of the lanthanide oxide clusters. Herein, by combining the photoelectron imaging spectroscopy and density functional theory (DFT) calculations, the electronic structure of GdO was investigated. An electron affinity (EA) of 1.16 +/- 0.09 eV is obtained, and the measured anisotropy parameter (beta) provides direct experimental evidence about the orbital symmetry of the detached electron in GdO-. DFT calculations have been employed to acquire the optimized geometries of the GdOn-1/0 (n = 2-4) clusters, and multiple activated oxygen species, which are radical, peroxide, superoxide, triradical, and ozonide radical, are found in these oxide clusters. Simulated photoelectron spectra (PES) of the GdOn-1/0 (n = 2-4) clusters are examined, which may stimulate further experimental investigations on the gadolinium oxide clusters. In addition, the valence molecular orbitals (MOs) of these clusters are also discussed to reveal the interaction between the lanthanide metal (Gd) and O atoms.