Density functional theory in conjunction with small core pseudopotentials and the associated basis sets was used to calculate potentials for multiple redox couples, covering a range of oxidation states for Ac (0 to III), Th (0 to IV), and Pa (0 to V) in aqueous solution. Solvation effects were incorporated using a supermolecule-continuum approach, with 30 water molecules representing two solvation shells, and the COSMO and SMD implicit solvation models. The calculated geometries for Ac(III), Th(IV), and Pa(V) were in reasonable agreement with the available experimental data. Using the COSMO model with the B3LYP functional, the calculated redox potentials were within ± 0.2 V from experiment for most redox couples. Several pathways were explored for the Pa(V/IV) redox couple for different forms of Pa(V) and Pa(IV). Most Pa(V/IV) redox couples have very similar potentials, ranging from 0 to -0.4 V up to a pH of 1.4. At pH = 1.4, the potentials shift to values that are more negative than -0.7 V, reflecting the growing unfavorable nature of the redox process at higher pH levels. The calculated values for An(III/II) potentials were consistent with prior estimates and the available experimental data. The predicted redox potentials for An(II/I) were highly negative, as expected. For An(I/0) potentials, Th and Pa exhibited positive values, contrasting with the negative values calculated for Ac. Furthermore, the An+m/An(0) potentials agreed better with the experimental data when using the COSMO solvation model as compared to the SMD model.
Dutra, Felipe R., et al. "Prediction of Redox Potentials for Ac, Th, and Pa in Aqueous Solution." Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, vol. 128, no. 45, Oct. 2024. https://doi.org/10.1021/acs.jpca.4c05693
Dutra, Felipe R., Romeu, João G. F., & Dixon, David A. (2024). Prediction of Redox Potentials for Ac, Th, and Pa in Aqueous Solution. Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, 128(45). https://doi.org/10.1021/acs.jpca.4c05693
Dutra, Felipe R., Romeu, João G. F., and Dixon, David A., "Prediction of Redox Potentials for Ac, Th, and Pa in Aqueous Solution," Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory 128, no. 45 (2024), https://doi.org/10.1021/acs.jpca.4c05693
@article{osti_3004798,
author = {Dutra, Felipe R. and Romeu, João G. F. and Dixon, David A.},
title = {Prediction of Redox Potentials for Ac, Th, and Pa in Aqueous Solution},
annote = {Density functional theory in conjunction with small core pseudopotentials and the associated basis sets was used to calculate potentials for multiple redox couples, covering a range of oxidation states for Ac (0 to III), Th (0 to IV), and Pa (0 to V) in aqueous solution. Solvation effects were incorporated using a supermolecule-continuum approach, with 30 water molecules representing two solvation shells, and the COSMO and SMD implicit solvation models. The calculated geometries for Ac(III), Th(IV), and Pa(V) were in reasonable agreement with the available experimental data. Using the COSMO model with the B3LYP functional, the calculated redox potentials were within ± 0.2 V from experiment for most redox couples. Several pathways were explored for the Pa(V/IV) redox couple for different forms of Pa(V) and Pa(IV). Most Pa(V/IV) redox couples have very similar potentials, ranging from 0 to -0.4 V up to a pH of 1.4. At pH = 1.4, the potentials shift to values that are more negative than -0.7 V, reflecting the growing unfavorable nature of the redox process at higher pH levels. The calculated values for An(III/II) potentials were consistent with prior estimates and the available experimental data. The predicted redox potentials for An(II/I) were highly negative, as expected. For An(I/0) potentials, Th and Pa exhibited positive values, contrasting with the negative values calculated for Ac. Furthermore, the An+m/An(0) potentials agreed better with the experimental data when using the COSMO solvation model as compared to the SMD model.},
doi = {10.1021/acs.jpca.4c05693},
url = {https://www.osti.gov/biblio/3004798},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
issn = {ISSN 1520-5215},
number = {45},
volume = {128},
place = {United States},
publisher = {American Chemical Society},
year = {2024},
month = {10}}
University of Alabama, Tuscaloosa, AL (United States)
Sponsoring Organization:
São Paulo Research Foundation (FAPESP); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0018921
OSTI ID:
3004798
Journal Information:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 45 Vol. 128; ISSN 1089-5639; ISSN 1520-5215
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