Structural Characteristics, Population Analysis, and Binding Energies of [An(NO3)]2+ (with An = Ac to Lr)

Deborah A Penchoff; Charles C Peterson; Mark S Quint; John D Auxier 2nd; George K Schweitzer; David M Jenkins; Robert J Harrison; Howard L Hall

doi:10.1021/acsomega.8b01800

Structural Characteristics, Population Analysis, and Binding Energies of [An(NO₃)]²⁺ (with An = Ac to Lr)

ACS Omega. 2018 Oct 25;3(10):14127-14143. doi: 10.1021/acsomega.8b01800. eCollection 2018 Oct 31.

Authors

Deborah A Penchoff^{1

2}, Charles C Peterson³, Mark S Quint^{4

5}, John D Auxier 2nd⁶, George K Schweitzer⁷, David M Jenkins⁷, Robert J Harrison^{8

9}, Howard L Hall^{1

6

10}

Affiliations

¹ Institute for Nuclear Security, University of Tennessee, 1640 Cumberland Avenue, Knoxville, Tennessee 37996, United States.
² Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
³ Research Information Technology Services, University of North Texas, 225 South Avenue B, Denton, Texas 76201, United States.
⁴ Department of Nuclear Engineering, University of Tennessee, 301 Middle Drive, Pasqua Nuclear Engineering Building, Knoxville, Tennessee 37996, United States.
⁵ US Army Nuclear and Countering Weapons of Mass Destruction Agency (USANCA), United States Army, Ft. Jackson, South Carolina 29715, United States.
⁶ Radiochemistry Center of Excellence (RCOE), University of Tennessee, 1508 Middle Drive, Ferris Hall, Knoxville, Tennessee 37996, United States.
⁷ Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, United States.
⁸ Institute for Advanced Computational Science, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11790, United States.
⁹ Brookhaven National Laboratory, Computational Science, Building 725, Upton, New York 11973, United States.
¹⁰ Y-12 National Security Complex, Oak Ridge, Tennessee 37830, United States.

Abstract

Efficient predictive capabilities are essential for the actinide series since regulatory constraints for radioactive work, associated costs needed for specialized facilities, and the short half-lives of many actinides present great challenges in laboratory settings. Improved predictive accuracy is advantageous for numerous applications including the optimization and design of separation agents for nuclear fuel and waste. One limitation of calculations in support of these applications is that the large variations observed from predictions obtained with currently available methods can make comparisons across studies uncertain. Benchmarking currently available computational methodologies is essential to establish reliable practices across the community to guarantee an accurate physical description of the systems studied. To understand the performance of a variety of common theoretical methods, a systematic analysis of differences observed in the prediction of structural characteristics, electron withdrawing effects, and binding energies of [An(NO₃)]²⁺ (with An = Ac to Lr) in gas and aqueous phases is reported. Population analysis obtained with Mulliken and Löwdin reflect a large dependence on the level of theory of choice, whereas those obtained with natural bond orbital show larger consistency across methodologies. Predicted stability across the actinide series calculated with coupled cluster with perturbative doubles and triples at the triple ζ level is equivalent to the one obtained when extrapolated to the complete basis set limit. The ground state of [Fm(NO₃)]²⁺ and [Md(NO₃)]²⁺ is predicted to have an electronic structure corresponding to An III state in gas and An IV in aqueous phase, whereas the ground state of [An(NO₃)]²⁺ (with An = Ac to Es, Lr) presents an electronic structure corresponding to An IV in the gas and aqueous phase. The compounds studied with No in gas and aqueous phase present a preferred No III state, and the Lr compounds did not follow trends predicted for the rest of the actinide series, as previously observed in studies regarding its unusual electronic structure relative to its position in the periodic table.