NpFn分子结构与电子结构的理论研究

A theoretical study onmolecular structure and electronic properties of NpF_n

运用杂化密度泛函（B3LYP）方法,对NpFn（n=3～6）的分子结构特性进行了系统地研究.优化得到了各分子的平衡几何构型,计算了分子的振动频率,并进行了态密度和自然键价轨道（NBO）分析.讨论了不同芯电子相对论有效原子芯势（RECP）对计算结果的影响,分析了NpFn分子的成键,发现随着与Np结合的F原子数目增加,Np原子的5f与F原子的2p轨道能逐渐接近,成键依次增强,键长呈现出收缩的趋势.目前的计算结果与可行的理论和实验符合较好.

The molecular properties of NpFn （n=3～6） molecules have been investigated by using hybrid density functional theory.The equilibrium geometrical structures of NpFn molecules are obtained in the geometry optimization.The vibrational frequencies,density of states and natural bonding orbital are calculated.A special discussion has been carried out on the influence of different relativistic effective core potentials （RECP）.The orbital energy between the neptunium 5f orbital and the fluorine 2p orbital is becoming more and more close when the number of F atom in NpFn molecules is increasing,resulting more strong Np-F bond and the bond lengths in NpFn molecules are shorten.It is found that the present calculations are in good agreement with the available experimental and theoretical results.