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采用DFT/B_3LYP方法研究了化合物Mo(CO)_n~+(n=1～6)的基态可能构型,对于各n值,基态可能构型(电子态)依次为:直线型(~6∑~+),直线型(~6∑_g~+),C_(2v)(~2A_2)或D_(3h)(~6A_1),D_(4h)(~4A_(lg)),C_(2v)(~2B_2)或 C_(4v)＇(~2B_1),D_(3d)(~2A_(lg)).计算结果表明,对于n≥3时,碎片离子的构型与体系自旋多重度关系敏感.进一步计算了Mo-CO键的逐级解离能,计算值与实验结果能较好吻合,并从Mo原子4d和5s轨道杂化角度来解释该键解离能随n值的非单调变化.
The possible configurations of the ground states of the Mo (CO) _n ~ + (n = 1 ~ 6) compounds are studied by DFT / B_3LYP method. The possible configurations of the ground states for each n value are: (~ 6Σ_g ~ +), C_ (2v) (~ 2A_2) or D_ (3h) (~ 6A_1), D_ (4h) ~ 4A_ (lg) ~ 2B_2) or C_ (4v) ’(~ 2B_1) and D_ (3d) (~ 2A_ (lg)). The calculated results show that for n≥3, the configuration of fragment ions is sensitive to the spin multiplicity of the system. The step-by-step dissociation energies of Mo-CO bond are calculated. The calculated values agree well with the experimental results. The dissociation energy of the bond with n-value is explained by the orbital hybridization of Mo atom for 4d and 5s.