在密度泛函理论框架下,应用不同泛函计算了配合物N i(CO)n(n=1~4)的平衡几何构型和振动频率.考察了泛函和基组重叠误差对预测N i—CO键解离能的影响.计算结果表明,用杂化泛函能得到与实验一致的优化几何构型和较合理的振动频率.对N i(CO)n(n=2~4)体系,用“纯”泛函,如BP86和BPW 91,可得到与CCSD(T)更符合、并与实验值接近的解离能.当解离产物出现单个金属原子或离子(如金属羰基配合物的完全解离)时,BSSE校正项的计算中应保持金属部分的电子结构一致.只有考虑配体基组和不考虑配体基组两种情况下金属的电子构型与配合物中金属的构型一致时,才能得到合理的BSSE校正,从而预测合理的解离能. In the framework of density functional theory, the equilibrium geometries and vibrational frequencies of the complexes N i (CO) n (n = 1 ~ 4) were calculated by using different functionalities. (CO) n (n = 2 ~ 4) were obtained by using the hybrid functional theory, and the optimal geometric configurations and the more reasonable vibration frequencies were obtained. System, with “pure” functionalities, such as BP86 and BPW 91, a dissociation energy can be obtained which is more in line with the CCSD (T) and close to the experimental value.When the dissociation products have single metal atoms or ions (such as metal carbonyl coordination Completely dissociation of matter), the electronic structure of the metal part should be kept consistent in the calculation of the BSSE correction term. Only considering the electron configuration of the metal in both the ligand-based group and the ligand- When the configurations are consistent, a reasonable BSSE correction can be obtained to predict the reasonable dissociation energy.