中文摘要：

用二阶微扰方法（MP2）和单组态相互作用方法（CIS）方法优化了M（CO）4（Mic）2（M=Cr,Mo,W）的基态和激发态的几何结构,并用含时密度泛函方法（TD-DFT）计算了M（CO）4（Mic）2（M=Cr,Mo,W）的光谱.结果表明：在激发态,金属原子与相邻原子间的键相对基态减弱;Cr（CO）4（Mic）2的最低能量磷光光谱为773.1nm,主要归结为伴有CO（p）→Cr（d）跃迁（LMCT）的Mic（p）→Cr（d）（LMCT）跃迁;Mo（CO）4（Mic）2的最低能量磷光光谱为639.3nm,主要归结为伴有Mic-other（p）→Mo（d）跃迁（LMCT）的Mic-other（p）→O（p）跃迁（ILCT）;W（CO）4（Mic）2的磷光光谱为640.5nm,主要归结为伴有Mic-other（p）→W（d）跃迁（LMCT）的Micother（p）→O（p）跃迁（ILCT）;Mo和W配合物的发光跃迁属性表现出相似性,但与Cr配合物存在明显差异.由于Cr原子与相邻原子的相互作用明显强于Mo和W原子,所以Cr原子对配合物跃迁的贡献较Mo和W的更大.

英文摘要：

The ground- and excited-state structures of M（CO）4 （Mic）2 （M=Cr,Mo,W） are optimized by the MP2 and CIS methods, respectively. On the basis of the MP2- and CIS-optimized structures, the TD-DFT method is employed to calculate the spectra of M（CO）4 （Mic）2 （M= Cr, Mo, W）. The results show that the bonds between metal atom and adjacent atoms in excited-states are weaker than in ground states and the lowest-energy phosphorescent emission of Cr（CO）4 （Mic）2 is 773. 1 nm,which mainly has Mic（p）→Cr（d） （LMCT） accompanied by CO（p）→Cr（d） （LMCT） ,and the lowest-energy phosphorescent emission of Mo（CO）4 （Mic）2 is 639.3 nm,which mainly has Mie-other（p）→O（p） （ILCT） accompanied by Mic-other（p）→Mo（d） （LMCT）,and the lowest-energy phosphorescent emission of W（CO）4 （Mic）2 is 640.5 nm, which mainly has Mie-other （p） → O （p） （ILCT） accompanied by Mic-other （p）→W （d） （LMCT）. It is found that the properties of luminescence of Mo （CO） 4 （Mic） 2 and W （CO）4 （Mic） 2 are similar and the properties of luminescence of Mo（CO）4 （Mic）2 and Cr（CO）4 （Mic）2 are obviously different. It is summarized that Cr atom has more effect in transition of complex than Mo and W atom because the interaction between Cr atom and adjacent atoms is stronger than the interaction between Mo atom and adiacent atoms and the interaction between W atom and adjacent atoms.