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采用MP2(full)/6-311G(d,p)从头算方法,优化了硝基甲烷和甲基自由基吸氢反应的过渡态结构,经QCISD(T)方法进行能量校正,得出该反应的正逆向反应的活化位垒分别是58.21kJ·mol-1和67.17kJ·mol-1.沿IRC分析指出该反应是氢转移协同反应,而且在反应途径上存在一个引导反应进行的振动模式,这一反应模式引导反应进行的区间在反应坐标S的-0.9～1.0(amu)1/2bohr之间;在温度为800～2600K范围内,运用改进的变分过渡态理论(ICVT),计算了该反应的速率常数,并与实验类比所得的速率常数随温度的变化趋势进行了比较.
The MP2 (full) / 6-311G (d, p) ab initio method was used to optimize the transition state structure of the nitromethane and methyl radical hydrogen absorption reactions and the energy was corrected by the QCISD (T) method. The activation barriers for the forward and reverse reactions are 58.21kJ · mol-1 and 67.17kJ · mol-1, respectively. IRC analysis indicates that the reaction is a hydrogen transfer synergetic reaction, and there is a vibrational mode that leads the reaction in the reaction pathway. The reaction mode leads the reaction in the range of -0.9 ~ 1.0 (amu) 1 / 2bohr of the reaction coordinate S. In the temperature range of 800 ~ 2600K, using the improved variational transition state theory (ICVT) The rate constants of the reaction are compared with those obtained from the experimental analogies.