酸根离子及其水溶液对镎酰离子结构性质的影响

The influence of ligands on the structural properties of neptunyl ion in gaseous and aqueous phases

利用B3LYP杂化密度泛函方法,在相对论有效芯势模型下,优化得到了NpO_2^(2+)离子及其配合物在气相和水溶液中的几何结构和电子结构,研究了NO-3、SO2-4和CO2-3离子及其水溶液对NpO_2^(2+)离子的结构和性质的影响.结果表明,NpO_2^(2+)离子结合各种酸根离子后其Np=O键的键长都有明显增长、Np和O原子的价电子轨道能均有升高,而考虑溶剂化效应后酸根离子的影响将减小.电荷分析发现,结合酸根离子后,NpO_2^(2+)中Np和O原子间形成的共价键的强度减弱、键长增长.对NpO_2^(2+)离子与三种酸根离子的理论结合能的比较显示,Np O2CO3分子最为稳定.

The geometries and electronic structures of NpO2^2＋ ions and Neptunyl complexes were obtained by u-sing the relative effective core potential （RECP） at density functional theory （DFT）.The influence of ligands on the structural properties of NpO2^2＋ ions in gaseous and aqueous phases has been discussed .After NpO2＋2 ions binding ligands , Np=O bond length is longer , O=Np=O axial bond is bent , the bond energies from the val-ance orbitals of Np and O are increased .The influence of ligands on the structural properties of NpO2^2＋ ions was reduced after considering solvation effects .Electron density analysis indicates that the overlap between neptunium and the axial two oxygen atoms is diminished with NpO2^2＋ ions binding ligands , as a result , the Np =O axial bond distance is elongated.Finally, according to the calculated binding energies among the three ligands and NpO2^2＋ ions, NpO2 CO3 is found to be the most stable molecule among the three Neptunyl complexes .