中文摘要：

通过对铀采用相对赝势基组,其它原子使用6-31＋G（d）基组,应用密度泛函理论（DFT）以及B3LYP方法对UO22＋离子与F-、CO23-和NO-3的各配位结构进行优化和频率计算.计算考虑了气相和水溶剂化两种状态,其中溶剂化模型采用连续导体介质理论模型（CPCM）.计算结果显示配体的配位数与O襒U襒O对称伸缩振动频率存在线性关系.配体在气相和水溶液中存在的关系基本符合通式：νs=-Agasn＋983和νs=-Aaqn＋821（Agas和Aaq为常数,表示每增加一个配体振动频率的变化值;n为配体配位数）.其中F-对应Agas=53cm^-1,Aaq=11cm^-1;CO230-对应Agas=85cm^-1,Aaq=19cm^-1;NO-3对应Agas=48cm^-1,Aaq=-10cm^-1.并且Aaq值与实验值一致.

英文摘要：

The geometries and IR frequencies of uranyl complexes were calculated by B3LYP method in density functional theory （DFT） using the relative effective core potential （RECP） on uranium and 6-31＋G（d） basis set on other elements. Both gaseous and aqueous phases were considered and conductor-like polarized continuum model（CPCM） was used to consider the solvation effect of water. Ligands investigated in the present paper were F-,CO230-,and NO3-. A linear correlation between the frequency of the O=U=O symmetrical stretching vibration and the number （n） of ligands was established for the above-mentioned ligands according to the following two equations：νs=-Agasn＋983 and νs=-Aaqn＋ 821,where Agas and Aaq are characteristic coefficients that represent the shift in vibrational frequency for the addition of each ligand to the uranyl center. Results obtained for F-fit the equations with Agas=53 cm-1 and Aaq=11 cm-1; CO230-with Agas=85 cm-1 and Aaq=19 cm-1; NO3-with Agas=48 cm-1 and Aaq=-10 cm-1. The value of Aaq was found to correspond to the experimental results.