Monohafnium oxide clusters HfO(n)- and HfO(n) (n = 1-6): oxygen radicals, superoxides, peroxides, diradicals, and triradicals.
The electronic and structural properties of monohafnium oxide clusters, HfO(n)(-) and HfO(n) (n = 1-6), are investigated using anion photoelectron spectroscopy and density-functional theory at the B3LYP level. The observed ground-state adiabatic detachment energy is low for HfO(-) (0.5 ± 0.1 eV) and HfO(2)(-) (2.125 ± 0.010 eV), roughly constant for HfO(3)(-) (3.6 ± 0.1 eV), HfO(4)(-) (3.67 ± 0.05 eV), and HfO(5)(-) (3.9 ± 0.1 eV), and substantially higher for HfO(6)(-) (4.9 ± 0.1 eV). Activated oxygen species, such as radical, superoxide, peroxide, diradical, and triradical, are identified in the HfO(n)(-) and HfO(n) clusters. The Hf center is shown to be flexible to accommodate the oxygen species. The sum of formal Hf-O bond orders around the Hf center is equal to four for all of the neutral clusters studied, and five for all of the anions. The O-rich HfO(n)(-) and HfO(n) (n = 3-6) clusters provide well-defined molecular models to understand O(2) adsorption and activation on an Hf center.
Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
Hua-Jin
HJ
Zhai
Wen-Jie
WJ
Chen
Shu-Juan
SJ
Lin
Xin
X
Huang
Lai-Sheng
LS
Wang