Reliable Potential Energy Surfaces for the Reactions of H2O with ThO2, PaO2+, UO22+, and UO2+

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• 作者：Monica Vasiliu ; Kirk A. Peterson ; John K. Gibson ; David A. Dixon
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 19, 2015
• 年：2015
• 卷：119
• 期：46
• 页码：11422-11431
• 全文大小：380K
• ISSN：1520-5215

文摘

The potential energy surfaces for the reactions of H₂O with ThO₂, PaO₂⁺, UO₂²⁺, and UO₂⁺ have been calculated at the coupled cluster CCSD(T) level extrapolated to the complete basis set limit with additional corrections including scalar relativistic and spin鈥搊rbit. The reactions proceed by the formation of an initial Lewis acid鈥揵ase adduct (H₂O)AnO₂^0/+/2+ followed by a proton transfer to generate the dihydroxide AnO(OH)₂^0/+/2+. The results are in excellent agreement with mass spectrometry experiments and prior calculations of hydrolysis reactions of the group 4 transition metal dioxides MO₂. The differences in the energies of the stationary points on the potential energy surface are explained in terms of the charges on the system and the populations on the metal center. The use of an improved starting point for the coupled cluster CCSD(T) calculations based on density functional theory with the PW91 exchange鈥揷orrelation functional or Brueckner orbitals is described. The importance of including second-order spin鈥搊rbit corrections for closed-shell molecules is also described. These improvements in the calculations are correlated with the 5f populations on the actinide.