过渡金属铁团簇Fe4和NO反应的密度泛函理论研究

摘要

The reaction mechanism of Fe4 +NO (14-et and 16-et) was studied by using the B3LYP method combined with 6 -311 +G ( d, P) basis set. The geometry configurations of reactants, transition states and products on 14-et and 16-et potential energy surfaces ( PES) were acquired, and all the transition states were verified by the vibration analysis and the intrinsic reaction coordinate calculations ( IRC) . Comparing the reac-tion mechanisms on the two PESs, it is found that they are similar. The results showed that the reaction is a three-step reaction, and C1→TS1 is rate-limiting step. Because of the crossing point ( CP) between two PESs, the activation energy of reaction can be lowered effectively, which benefits the kinetic and thermodynamic aspects of this catalytic reaction.%采用密度泛函理论中的B3LYP方法在6-311+G( d,p)计算水平上研究了第一过渡系金属铁团簇Fe4在基态和第一个激发态与NO的反应机理。全参数优化了体系中十四重态以及十六重态反应势能面上的各驻点结构,并用频率分析法和内禀反应坐标法对过渡态进行了验证。通过对反应过程的分析发现,反应在十四重态以及十六重态势能面上的反应机理是相似的。而且,该反应是一个三步反应,其中C1→TS1键是整个反应的决速步。由于势能交叉点的存在,可以有效降低反应的活化能,这在热力学和动力学上都是非常有利的。