Photoelectron spectroscopy of B{sub 4}O{sub 4}{sup −}: Dual 3c-4e π hyperbonds and rhombic 4c-4e o-bond in boron oxide clusters
- Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006 (China)
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)
Gas-phase anion photoelectron spectroscopy (PES) is combined with global structural searches and electronic structure calculations at the hybrid Becke 3-parameter exchange functional and Lee-Yang-Parr correlation functional (B3LYP) and single-point coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)) levels to probe the structural and electronic properties and chemical bonding of the B{sub 4}O{sub 4}{sup 0/−} clusters. The measured PES spectra of B{sub 4}O{sub 4}{sup −} exhibit a major band with the adiabatic and vertical detachment energies (ADE and VDE) of 2.64 ± 0.10 and 2.81 ± 0.10 eV, respectively, as well as a weak peak with the ADE and VDE of 1.42 ± 0.08 and 1.48 ± 0.08 eV. The former band proves to correspond to the Y-shaped global minimum of C{sub s} B{sub 4}O{sub 4}{sup −} ({sup 2}A″), with the calculated ADE/VDE of 2.57/2.84 eV at the CCSD(T) level, whereas the weak band is associated with the second lowest-energy, rhombic isomer of D{sub 2h} B{sub 4}O{sub 4}{sup −} ({sup 2}B{sub 2g}) with the predicted ADE/VDE of 1.43/1.49 eV. Both anion structures are planar, featuring a B atom or a B{sub 2}O{sub 2} core bonded with terminal BO and/or BO{sub 2} groups. The same Y-shaped and rhombic structures are also located for the B{sub 4}O{sub 4} neutral cluster, albeit with a reversed energy order. Bonding analyses reveal dual three-center four-electron (3c-4e) π hyperbonds in the Y-shaped B{sub 4}O{sub 4}{sup 0/−} clusters and a four-center four-electron (4c-4e) π bond, that is, the so-called o-bond in the rhombic B{sub 4}O{sub 4}{sup 0/−} clusters. This work is the first experimental study on a molecular system with an o-bond.
- OSTI ID:
- 22415609
- Journal Information:
- Journal of Chemical Physics, Vol. 142, Issue 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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