摘要
采用密度泛函理论(B3LYP)方法,钚原子采用相对论有效原子实势(RECP)SDD基组,氢、氧原子采用aug-cc-pVTZ全电子基组,优化了PuO2的分子结构,得到了相应的平衡几何构型。同时优化了Pu—H2O的4个稳定异构体。比较能量发现水分子易于解离,从而与Pu形成更稳定的结构。由于Pu与O原子的电负性相差很大易发生电荷转移,分子的稳定性主要源于Pu—O之间的相互作用。根据电子-振动近似理论,计算了不同温度下金属Pu与H2O吸附与解离反应的生成热力学函数。计算表明,即使在低温下,H2O蒸汽分子也无法在金属钚表面形成分子吸附,相反,在金属钚表面水分子的解离可自发进行。
Employing density functional method(B3LYP) with the relativistic effective core potential(RECP) for Pu atom and all-electron basis set aug-cc-pVTZ for O and H atoms,the equilibrium geometrical structures of PuO2 molecule were optimized.In addition,four structures for Pu-water were proposed and studied.The results indicate that water molecule tends to dissociate to form more stable structure with Pu.Due to the lager difference of electronegativity for Pu and O atoms,the stable structure is from the interaction of Pu and O atoms.The thermodynamic functions of adsorption and dissociation reactions of Pu and H2O were calculated according to electronic-vibration approximation.The results show that the water vapor molecule can’t adsorb on Pu surface even at low temperature,in contrast,dissociation reactions of H2O on Pu surface can occur spontaneously.
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2012年第9期1028-1033,共6页
Atomic Energy Science and Technology
关键词
分子结构
密度泛函
相对论有效原子实势
热力学函数
molecule structure
density functional theory
relativistic effective core potential
thermodynamical function