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Supporting dataset for First-principles Quantum Chemical Studies on Reaction of Hydrogen Superoxide with Water and Sulfur Dioxide at Supercritical Conditions
As people pay more and more attention to the air pollution, it is particularly essential to study the chemical reaction mechanism in atmospheric reactions. Hydrogen-oxygen species such as OH, HO2, H2O2, and H2O are important in atmospheric chemistry, and their reaction mechanisms deserve further study. However, due to the extremely high cost of calculation, the accuracy of electronic structure calculation was relatively low in past studies, resulting in unclear reaction mechanism explanations in the calculation of low-barrier reactions. In this study, we combined high-precision electronic structure calculation with machine learning (ML) methods and proposed more reasonable reaction mechanisms.
To get better understanding of the atmospheric reaction mechanism, both the HO2 radical reacts with the most abundant greenhouse gas water vapor as well as the SO2 molecule were investigated in the thesis. the full-dimensional full-scale energy surface (PES) with high precision using the ab initio electronic structure calculation method were constructed for further calculation with higher accuracy. Different from traditional research, we use the ML method, fitting the PES by PIP-NN method within minimal error, and molecular dynamics simulation is performed to obtain effective trajectories. To get more accurate rate constant, both traditional TST and CVT methods, as well as the quasi-classical trajectory based on the fitting PES were used.
The results calculated helped to understand the mechanism of the atmospheric well. As the calculated results have great agreement with the experimental results, we can explain these reactions in theoretical dimension. From our calculations, we acquired the catalyst effect of HO2 radical and H2O molecules, and from the simulated mostly possible trajectory based on the transition state structure we found, we get the rate constant which corresponds greatly to the experimental results. Our calculation and simulation results can confirm the reaction mechanism between air pollutants and HO2 molecules.