铁原子与SO_2反应的密度泛函理论研究

采用密度泛函理论(DFT)中的B3LYP方法在6-311+G(d,p)的计算水平上研究了铁原子与SO_2在三重态以及五重态反应势能面上的反应机理.全参数优化了三重态以及五重态反应势能面上各驻点的几何构型,并用频率分析法以及内禀反应坐标(IRC)方法对过渡态进行了验证,得到了该反应的反应势能面曲线和微观反应路径.结果表明,铁原子与SO2在三重态与五重态反应势能面上的几何构型相似,三重态的能量均比五重态高,说明铁原子与SO_2的反应主要在五重态反应势能面上进行.整个体系为放热反应,反应的活化能为30.6 k Cal/mol.

Theoretical study on the reaction of Fe and SO2 based on Density Functional Theory

In this paper, the reaction of Fe+SO2 (triplet and quintet) was calculated by the Density Functional Theory with the B3LYP method compiled with the 6-311+G (d, p) basis set. The geometry optimizations of reactants, transition states, intermediates and products of the reactions of triplet and quartet states were completely optimized, and all the transition states were verified by the vibration analysis and the intrinsic reaction coordinate calculations. The optimized geometry of quintet and triplet potential energy surfaces (PES) are similar, but all values of the energy of saddle points on triplet PES are higher than the quintet''s, hence, the reaction on the triplet state PES is not favorable. The result shows that the reaction is exothermic, and the activation energy is 30.6kCal/mol.