中文摘要：

采用CCSD（T）/aug-cc-pVTZ//B3LYP/6-311＋G（2df,2p）方法对HO2＋H2S反应及单分子水参与其主通道的微观机理和速率常数进行了研究.结果表明,HO2＋H2S反应主通道为生成产物为H2O2＋HS的通道,其表观活化能为14.94 kJ/mol.考虑单分子水对主产物通道的影响发现,所得的势能面比无水参与的反应复杂得多,经历了H2O…HO2＋H2S（RW1）,HO2…H2O＋H2S（RW2）和H2O…H2S＋HO2（RW3）3个通道,RW1-RW6共6个路径.其中通道RW1是水分子参与HO2＋H2S反应主通道的优势通道.在216.7-298.2K温度范围内通道RW1的有效速率常数呈现出正温度系数效应,在298 K时,k＇RW 1/ktotal达到54.2%,表明在实际大气环境中水分子对HO2＋H2S反应的主通道具有明显影响.

英文摘要：

The reaction mechanism and rate constant for the major channel between HO2 and H2S, without and with a water molecule, were investigated theoretically at the CCSD （T）/aug-cc-pVTZ// B3LYP/6-311 ＋ G（2df, 2p） level. The goal of the present investigation is to determine how the single water molecule can affect the reaction mechanisms and kinetics for the major channel of HO2 ＋H2S reaction and estimate the importance of water effects on the major channel of HO2 ＋H2 S reaction. The calculated results show that the HO2 ＋HE S reaction mainly occurs through the channel of H2O2 ＋HS formation with the apparent activation energy of 14.94 kJ/mol. When one water molecule is added, the reaction mechanism of the major channel becomes quite complex yielding three different reaction channels of H2 O... HO2 ＋ H2 S （ RW1 ）, HO2… H2 O ＋ HE S （ RW2 ） and HEO...HES＋HO2（RW2）. For single water-catalyzed the major channel of HOE＋H2S reaction, channel RW1 is dominant and path RW1 is the most favorable. Additionally, to estimate the importance of channel RW1 in the atmosphere, its rate constant is evaluated using the conventional transition state theory with Wigner tunneling correction. The calculated results show that the effective rate constant of path RW1 increases with the temperature increases. At 298 K, the value of k＇Rw1/ktotal is up to 54. 2% , indicating that the single water molecule has a obvious effect on the major channel of atmospheric reaction of HOE ＋H2S. The present study provides further insight into water effects in the atmospheric chemistry.