化学
反应速率常数
单重态
动力学
反应机理
大气温度范围
二甲基硫醚
臭氧
势能面
物理化学
计算化学
分子
热力学
激发态
有机化学
原子物理学
硫黄
物理
量子力学
催化作用
作者
Shuangjun Wang,Hui Zhao,Dong Chen,Chenggang Lu,Yizhen Tang
摘要
Abstract The potential energy surface (PES) for the reaction of ozone with dimethyl sulfide (DMS) was calculated at the CCSD(T)/6‐311++G(3df,2pd)//M06‐2X/6‐311++G(d,p) levels of theory. Result shows that on the singlet PES the addition–elimination mechanism is dominant, and H‐abstraction mechanism is less competitive. The major channel starts from the addition of ozone and DMS leading to a weak intermediate IM1, which decomposes subsequently to DMSO and 1 O 2 via a barrier around 38.8 kJ/mol. With a barrier of 64.0 kJ/mol, the formation of HO 3 + CH 3 SCH 2 via H‐abstraction mechanism is subdominant. Besides, DMSO + 1 O 2 can take place further reactions to produce several products. The substitution mechanism was located on the triplet PES, however, with a rather high barrier it is negligible. Furthermore, the rate constants for the two channels leading to DMSO + 1 O 2 and HO 3 + CH 3 SCH 2 were calculated from 200 to 1000 K. The total rate constant is 1.13 × 10 ‐20 cm 3 ·molecule ‐1 ·s ‐1 at 298 K and 1 atm, in good agreement with previous experimental data. The overall rate constants are positive temperature dependent in the whole temperature range.
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