Study of Hydration and Hydrolysis of Pu(IV) by the Density Functional Method
M. K. GANUSOVA1, E. A. IVANOVA-SHOR1,2, A. M. SHOR2, V. A. NASLUZOV2, A. I. RUBAYLO1,2
1Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
2Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
Keywords: density functional method, plutonium (IV) complexes, the polarizable continuum model, hydrolysis constants, hydration free energy
Pages: 239-246
Abstract
The structure and the first hydrolysis step of the hydrated Pu(IV) ion in the aquatic environment were studied using relativistic density functional theory and the polarizable continuum model (PCM). According to calculations, the Pu(IV) ion was mainly coordinated with eight water molecules. The calculated distance Pu-O of 238-241 pm was in good agreement with the experimental value ((239±2) pm). It was demonstrated that for the correct replication of constants log K 01 of the first hydrolysis step, it was important to use scaling multipliers adequate to the charge of the hydrated complex when constructing the density that included the solvated complex in PCM model. The calculated values of log K 01 of 1.1…-0.2 were close to the experimentally defined range (-0.6…0.6). The correct replication of hydrolysis constants allowed considering the calculated range of the hydratation free energies of the Pu(IV) ion of 6070-6157 kJ/mol as a reasonable prediction of experimental values.
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