Catalytic effect of water on the HO3 + NO formations from the HNO + O3 reaction in tropospheric conditions

Abstract

ABSTRACTA comprehensive investigation of the roles of water catalysts on O3 with HNO in the troposphere has been carried out by quantum chemical calculations at the CCSD(T)/aug-cc-pVTZ//M06-2X/6-311++G(2d,2p) levels of theory. Besides, the AIMD (ab initio Molecular Dynamics) simulation also used to help us to understand the mechanism of this reaction. The results show that the HNO + O3 reaction undergoes a channel for the formation of NO + HO3 and overcomes the energy barrier of 1.60 kcal·mol−1. After adding water molecules, the obtained product did not change, but the potential energy surface was much more complicated than the bare reaction, and it went through four reaction channels of HNO···H2O + O3, H2O···HNO + O3, H2O···O3 + HNO and O3···H2O + HNO. Among them, the channel HNO···H2O + O3 is the dominant channel for water molecules to participate in the reaction. Overall, these results show how water catalyzed the gas-phase reactions under atmospheric conditions.