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Thermodynamical Stability of Plutonium Monoxide with Carbon Substitution C
- Qiu, Ruizhi, Wang, Xin, Zhang, Yongbin, Ao, Bingyun, Liu, Kezhao
- Journal of physical chemistry 2018 v.122 no.40 pp. 22821-22828
- carbon, carbon dioxide, carbon monoxide, chemical bonding, models, oxygen, plutonium
- The existence of condensed plutonium monoxide (PuO) has long been controversial, in which carbon element plays a vital role. In this work, we modeled PuO with carbon substitution of oxygen as the special quasirandom structures of NaCl-type plutonium monoxycarbide (PuOₓC₁–ₓ) and performed first-principles calculations on these models. It is found that PuO could indeed be stabilized by carbon substitution. The amount of carbon element to stabilize PuO is very small if the source of carbon is CO or CO₂. If the carbon is contributed by plutonium monocarbide, the range of stable PuOₓC₁–ₓ agrees well with the experimental result. By analyzing the electronic structures and chemical bonds, we ascribe the stabilization of PuO by carbon substitution to the newly established Pu 5f/6d–C 2p hybridization around the Fermi level, i.e., stronger Pu–C bonds.