Br+CH3S(O)CH3反应机理的直接动力学研究

采用直接动力学的方法，对多通道反应体系Br＋CH3S（O）CH3进行了理论研究．在BH＆H-LYP／6-311G（2d，2p）水平下获得了优化几何构型、频率及最小能量路径（MEP），能量信息的进一步确认在MC-QCISD（单点）水平下完成．利用正则变分过渡态理论，结合小曲率隧道效应校正（CVT／SCT）方法计算了该反应的两个可行的反应通道在200K～2000K温度范围内的速率常数．在整个反应区间内，生成HBr的反应通道与生成CHa的反应通道存在着竞争，前者是主反应通道，后者是次反应通道．变分效应和小曲率隧道效应对反应速率常数的计算影响都很小．理论计算得到的两个反应通道的反应速率常数与实验值符合得很好．

Direct dynamic study on the reaction Br + CH3S(O)CH3

Theoretical investigations are carried out on the multi-channel reaction Br + CH_(3)S(O)CH_(3) by means of direct dynamic methods.The optimized geometries,frequencies and minimum energy path(MEP) is obtained at the BH&H-LYP/6-311G(2d,2p) level,and energetic information is further refined at the MC-QCISD(single-point) level.The rate constants for the title reaction are calculated by canonical variational transition state theory(CVT) with small-curvature tunneling(SCT) correction in the temperature range 200 K~2 000 K.The rate constant for the reaction channel to yield HBr is the major channel.The reaction channel to yield CH_(3) is minor channel all the time over the whole temperature region.Both the variational effect and the tunneling effect are small over the whole temperature region.The theoretical rate constant of two reaction channels are in good agreement with the available experimental data.