The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol （CH3OH） by the CIO radical has been investigated using ab initio calculations. The reaction proce...The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol （CH3OH） by the CIO radical has been investigated using ab initio calculations. The reaction proceeds through two channels： abstraction of the hydroxyl H-atom and methyl H-atom of CH30H by CIO, leading to the formation of CH30 ＋ HOC1 （＋H20） and CH20H ＋ HOC1 （＋ H20）, respectively. In both cases, pre- and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of CH2OH ＋ HOC1 （＋H20） is predominant over the formation of CH30 ＋ HOC1 （＋H20）, with ambient rate constants of 3.07 x 10^-19 and 3.01 x 10^-23 cm^3/（molecule.sec）, respectively, for the reaction without water. Over the temperature range 216.7-298.2 K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4-6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the CH30H ＋ ClO reaction under tropospheric conditions.展开更多
基金supported by the National Natural Science Foundation of China (nos. 21577080, 91644214, 21707080)the Shandong Natural Science Fund for Distinguished Young Scholars (JQ201705)+1 种基金the Postdoctoral Science Foundation of China (no. 11440077311071)High Performance Computing Center of Shandong University
文摘The influence of a single water molecule on the reaction mechanism and kinetics of hydrogen abstraction from methanol （CH3OH） by the CIO radical has been investigated using ab initio calculations. The reaction proceeds through two channels： abstraction of the hydroxyl H-atom and methyl H-atom of CH30H by CIO, leading to the formation of CH30 ＋ HOC1 （＋H20） and CH20H ＋ HOC1 （＋ H20）, respectively. In both cases, pre- and post-reactive complexes were located at the entrance and exit channel on the potential energy surfaces. Results indicate that the formation of CH2OH ＋ HOC1 （＋H20） is predominant over the formation of CH30 ＋ HOC1 （＋H20）, with ambient rate constants of 3.07 x 10^-19 and 3.01 x 10^-23 cm^3/（molecule.sec）, respectively, for the reaction without water. Over the temperature range 216.7-298.2 K, the presence of water is seen to effectively lower the rate constants for the most favorable pathways by 4-6 orders of magnitude in both cases. It is therefore concluded that water plays an inhibitive role on the CH30H ＋ ClO reaction under tropospheric conditions.
