Lai Chao, Hu Yin, Qiu Ruizhi
Science and Technology on Surface Physics and Chemistry Laboratory Mianyang 621908 Sichuan China
Institute of Materials, China Academy of Engineering Physics Mianyang 621907 Sichuan China
RSC Adv. 2020 Jun 30;10(42):24877-24881. doi: 10.1039/d0ra00477d. eCollection 2020 Jun 29.
The intriguing and controversial sub-stoichiometric behavior of plutonium mononitride is investigated here using first-principles calculations combined with special quasirandom structures. It is found that NaCl-type plutonium mononitride is stable for only stoichiometric levels, and the formation enthalpy of plutonium mononitride is in good agreement with others. By comparing with plutonium monocarbide, the main reason for the absence of sub-stoichiometric behavior is the lower N-2p orbital energy, resulting in less hybridization and weaker Pu-N bonds. The weaker Pu-N bonds cannot support the formation of vacancies.
本文采用第一性原理计算结合特殊准随机结构的方法，对氮化钚的有趣且具争议性的亚化学计量行为进行了研究。结果发现，NaCl型氮化钚仅在化学计量比水平下是稳定的，且氮化钚的生成焓与其他研究结果吻合良好。通过与碳化钚对比可知，不存在亚化学计量行为的主要原因是N - 2p轨道能量较低，导致杂化较少且Pu - N键较弱。较弱的Pu - N键无法支持空位的形成。
