| Autor: |
Long B; College of Materials Science and Engineering, Guizhou Minzu University, 550025 Guiyang, China., Xia Y; College of Materials Science and Engineering, Guizhou Minzu University, 550025 Guiyang, China., Bao JL; Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States., Carmona-García J; Institut de Ciència Molecular, Universitat de València, València 46071, Spain.; Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain., Gómez Martín JC; Instituto de Astrofísica de Andalucía, CSIC, Granada 18008, Spain., Plane JMC; School of Chemistry, University of Leeds, LS2 9JT Leeds, U.K., Saiz-Lopez A; Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain., Roca-Sanjuán D; Institut de Ciència Molecular, Universitat de València, València 46071, Spain., Francisco JS; Department of Earth and Environmental Sciences and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States. |
| Abstrakt: |
Sulfur trioxide is a critical intermediate for the sulfur cycle and the formation of sulfuric acid in the atmosphere. The traditional view is that sulfur trioxide is removed by water vapor in the troposphere. However, the concentration of water vapor decreases significantly with increasing altitude, leading to longer atmospheric lifetimes of sulfur trioxide. Here, we utilize a dual-level strategy that combines transition state theory calculated at the W2X//DF-CCSD(T)-F12b/jun'-cc-pVDZ level, with variational transition state theory with small-curvature tunneling from direct dynamics calculations at the M08-HX/MG3S level. We also report the pressure-dependent rate constants calculated using the system-specific quantum Rice-Ramsperger-Kassel (SS-QRRK) theory. The present findings show that falloff effects in the SO 3 + HONO 2 reaction are pronounced below 1 bar. The SO 3 + HONO 2 reaction can be a potential removal reaction for SO 3 in the stratosphere and for HONO 2 in the troposphere, because the reaction can potentially compete well with the SO 3 + 2H 2 O reaction between 25 and 35 km, as well as the OH + HONO 2 reaction. The present findings also suggest an unexpected new product from the SO 3 + HONO 2 reaction, which, although very short-lived, would have broad implications for understanding the partitioning of sulfur in the stratosphere and the potential for the SO 3 reaction with organic acids to generate organosulfates without the need for heterogeneous chemistry. |
