title: A joint photoelectron spectroscopy and theoretical study on the electronic structure of UCl5- and UCl5.
abstract: We report a combined photoelectron spectroscopic and relativistic quantum chemistry study on gaseous UCl5(-) and UCl5. The UCl5(-) anion is produced using electrospray ionization and found to be highly electronically stable with an adiabatic electron binding energy of 4.76±0.03 eV, which also represents the electron affinity of the neutral UCl5 molecule. Theoretical investigations reveal that the ground state of UCl5(-) has an open shell with two unpaired electrons occupying two primarily U 5f(z³) and 5f(xyz) based molecular orbitals. The structures of both UCl5(-) and UCl5 are theoretically optimized and confirmed to have C(4v) symmetry. The computational results are in good agreement with the photoelectron spectra, providing insights into the electronic structures and valence molecular orbitals of UCl5(-) and UCl5. We also performed systematic theoretical studies on all the uranium pentahalide complexes UX5(-) (X=F, Cl, Br, I). Chemical bonding analyses indicate that the U-X interactions in UX5(-) are dominated by ionic bonding, with increasing covalent contributions for the heavier halogen complexes.
authors.affiliation: Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China).
authors.forename: Jing
authors.initials: J
authors.lastname: Su
authors.forename: Phuong Diem
authors.initials: PD
authors.lastname: Dau
authors.forename: Chao-Fei
authors.initials: CF
authors.lastname: Xu
authors.forename: Dao-Ling
authors.initials: DL
authors.lastname: Huang
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Liu
authors.forename: Fan
authors.initials: F
authors.lastname: Wei
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
keywords: ab initio calculations; actinides; density functional calculations; photoelectron spectroscopy; uranium