title: Computational study of Th(4+) and Np(4+) hydration and hydrolysis of Th(4+) from first principles.
abstract: 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 ΔGSol0are 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, this [corrected] 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.
authors.affiliation: Faculdade de Biotecnologia, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, PA, 66075-110, Brazil.
authors.forename: Davi H T
authors.initials: DH
authors.lastname: Amador
authors.affiliation: Departamento de Matemática, Universidade Estadual Paulista (UNESP), PO Box 473, Bauru, SP, 17030-360, Brazil.
authors.forename: Julio R
authors.initials: JR
authors.lastname: Sambrano
authors.affiliation: Instituto de Física, Universidade de Brasília (UnB), PO Box 04455, Brasília, DF, 70919-970, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gargano
authors.affiliation: Faculdade de Biotecnologia, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA), Belém, PA, 66075-110, Brazil. lgm@ufpa.br.|Instituto de Física, Universidade de Brasília (UnB), PO Box 04455, Brasília, DF, 70919-970, Brazil. lgm@ufpa.br.
authors.forename: Luiz Guilherme M
authors.initials: LG
authors.lastname: de Macedo
keywords: Actinides in solution; DFT; Free energy of solvation of ions; Relativistic effects; Theoretical hydrolysis constants