Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
J Chem Phys. 2012 Aug 14;137(6):064315. doi: 10.1063/1.4742062.
The uranyl tetrachloride dianion (UO(2)Cl(4)(2-)) is observed in the gas phase using electrospray ionization and investigated by photoelectron spectroscopy and relativistic quantum chemical calculations. Photoelectron spectra of UO(2)Cl(4)(2-) are obtained at various photon energies and congested spectral features are observed. The free UO(2)Cl(4)(2-) dianion is found to be highly stable with an adiabatic electron binding energy of 2.40 eV. Ab initio calculations are carried out and used to interpret the photoelectron spectra and elucidate the electronic structure of UO(2)Cl(4)(2-). The calculations show that the frontier molecular orbitals in UO(2)Cl(4)(2-) are dominated by the ligand Cl 3p orbitals, while the U-O bonding orbitals are much more stable. The electronic structure of UO(2)Cl(4)(2-) is compared with that of the recently reported UO(2)F(4)(2-) [P. D. Dau, J. Su, H. T. Liu, J. B. Liu, D. L. Huang, J. Li, and L. S. Wang, Chem. Sci. 3 1137 (2012)]. The electron binding energy of UO(2)Cl(4)(2-) is found to be 1.3 eV greater than that of UO(2)F(4)(2-). The differences in the electronic stability and electronic structure between UO(2)Cl(4)(2-) and UO(2)F(4)(2-) are discussed.
四氯氧化铀二价阴离子（UO2Cl4(2-)）在气相中通过电喷雾电离被观察到，并通过光电子能谱和相对论量子化学计算进行了研究。在不同的光子能量下获得了 UO2Cl4(2-)的光电子能谱，并观察到了拥挤的光谱特征。游离的 UO2Cl4(2-)二价阴离子被发现具有非常高的稳定性，其绝热电子结合能为 2.40 eV。进行了从头算计算，并用于解释光电子能谱和阐明 UO2Cl4(2-)的电子结构。计算表明，UO2Cl4(2-)的前线分子轨道主要由配体 Cl 3p 轨道主导，而 U-O 成键轨道则稳定得多。UO2Cl4(2-)的电子结构与最近报道的 UO2F4(2-)进行了比较[P. D. Dau、J. Su、H. T. Liu、J. B. Liu、D. L. Huang、J. Li 和 L. S. Wang，Chem. Sci. 3, 1137 (2012)]。发现 UO2Cl4(2-)的电子结合能比 UO2F4(2-)高 1.3 eV。讨论了 UO2Cl4(2-)和 UO2F4(2-)之间在电子稳定性和电子结构方面的差异。
