Computational study of Th⁴⁺ and Np⁴⁺ hydration and hydrolysis of Th⁴⁺ from first principles

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• 作者：Davi H. T. Amador ; Julio R. Sambrano ; Ricardo Gargano…
• 关键词：Actinides in solution ; Relativistic effects ; DFT ; Free energy of solvation of ions ; Theoretical hydrolysis constants
• 刊名：Journal of Molecular Modeling
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：23
• 期：3
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Computer Applications in Chemistry; Molecular Medicine; Computer Appl. in Life Sciences; Characterization and Evaluation of Materials; Theoretical and Computational Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：0948-5023
• 卷排序：23

文摘

The aqueous solvation of Th and Np in the IV oxidation state was examined using cluster models generated by Monte Carlo simulations and density functional theory embedded within the COSMO continuum model to approximate the effect of bulk water. Our results suggest that the coordination number (CN) for both Th(IV) and NP(IV) should be 9, in accordance to some experimental and theoretical results from the literature. The structural values for average oxygen–metal distances are within 0.01 Å compared to experimental data, and also within the experimental error. The calculated ΔG_Sol0 are in very good agreement with experimental reported values, with deviations at CN = 9 lower than 1% for both Th(IV) and Np(IV). The hydrolysis constants are also in very good agreement with experimental values. Finally, our methodology has the advantage of using a GGA functional (BP86) that not only makes the calculations more affordable computationally than hybrid functional or ab initio molecular dynamics simulations (Car-Parrinello) calculations, but also opens the perspective to use resolution of identity (RI) calculations for more extended systems.