Theoretical study of two states reactivity of NO activation on iron atom

The mechanism of Fe+NO was calculated by the Density Functional Theory (DFT) with the B3LYP methods combined with the 6-311+G (d, p) basis set. The geometry of reactants, transition states, intermediates and products of two reaction systems were completely optimized, and all the transition states were verified by the vibration analysis and intrinsic reaction coordinate (IRC) calculations. The “Two State Reactivity (TSR)” was used to analyze the reaction mechanisms; Results showed that the reaction system preferentially involves low-spin state entrance channel and the high-spin state exit channel. In the reaction channel, the crossing point appears, which would effectively reduce the activation energy and increase the release of reaction heat, play a significant and beneficial role in the kinetic and thermodynamic aspects of this catalytic reaction.