title: On the electronic structure and chemical bonding in the tantalum trimer cluster.
abstract: The electronic structure and chemical bonding in the Ta 3 (-) cluster are investigated using photoelectron spectroscopy and density functional theory calculations. Photoelectron spectra are obtained for Ta 3 (-) at four photon energies: 532, 355, 266, and 193 nm. While congested spectra are observed at high electron binding energies, several low-lying electronic transitions are well resolved and compared with the theoretical calculations. The electron affinity of Ta 3 is determined to be 1.35 +/- 0.03 eV. Extensive density functional calculations are performed at the B3LYP/Stuttgart +2f1g level to locate the ground-state and low-lying isomers for Ta 3 and Ta 3 (-). The ground-state for the Ta 3 (-) anion is shown to be a quintet ( (5)A 1') with D 3 h symmetry, whereas two nearly isoenergetic states, C 2 v ( (4)A 1) and D 3 h ( (6)A 1'), are found to compete for the ground-state for neutral Ta 3. A detailed molecular orbital analysis is performed to elucidate the chemical boding in Ta 3 (-), which is found to possess multiple d-orbital aromaticity, commensurate with its highly symmetric D 3 h structure.
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China. ls.wang@pnl.gov
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Hua-Jin
authors.initials: HJ
authors.lastname: Zhai
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang