Computational study on the mechanisms and kinetics of the CH2BrO2 + ClO reaction in the atmosphere. Issue 41 (25th June 2020)

• Record Type: Journal Article
• Authors: Zhang, Yunju; Tang, Yizhen; He, Bing
• Is Part Of: RSC advances. Volume 10:Issue 41(2020)
• Page Start: 24308
• Page End: 24318
• Publication Date: 2020-06-25
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra10511e
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The singlet and triplet potential energy surfaces for the CH2 BrO2 + ClO reaction are studied at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d, p) level. Abstract : The singlet and triplet potential energy surfaces for the CH2 BrO2 + ClO reaction are studied at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d, p) level. CH2 BrO2 is revealed to react with ClO through two kinds of mechanisms on the triplet potential energy surface (PES), namely, SN 2 displacement and H-abstraction, and the production of P3 (CHBrO2 + HOCl) via H-abstraction is the dominant channel. Addition/elimination and SN 2 displacement mechanisms exist on the singlet PES and are more complicated. The RRKM calculations of the mechanism and product distribution in the CH2 BrO2 + ClO reaction show that the stabilization of IM1 (CH2 BrOOOBr) is dominant at T ≤ 600 K, while the pathway of producing P1 (CHBrO + HO2 + Cl) occupies the entire reaction at T > 600 K. The total rate constants are independent of pressure, while the individual rate constants are sensitive to pressure. The lifetime of CH2 BrO2 in the presence of ClO is estimated to be 20.27 h. Moreover, time-dependent density functional theory (TDDFT) calculations suggest that IM1 (CH2 BrOOOCl), IM2 (CH2 BrOOClO) and IM3 (CH2 BrOClO2 ) will photolyze under the sunlight.