H+O2(n0, j0)→HO+O及C+H2(n0, j0)→CH+H体系选态反应截面的过渡态理论计算

本文用微正则过渡态理论计算了H+O_2(n_0,j_0)→HO+O和C+H_2(n_0, j_0)→CH+H在ab initio势能面上的选态反应截面σ_(n_0,j_0); E.分析了势能面性质对反应截面的影响。计算结果表明, 在指定反应物分子的振动态n_0、转动态j_0时, 两个反应体系的反应截面随相对平动能的增加先是增加后是减小(j_0=1, n_0=0除外); 在给定相对平动能和反应物分子的转动态j_0时, 随反应物分子的振动量子数n_0的增加, 两个体系的选态反应截面均有较显著的增加, 在指定相对平动能和反应物分子的振动态n_0时, H+O_2体系的选态反应截面随j_0的变化较为复杂, 而C+H_2体系则比较简单(j_0=1除外)。对于H+O_2反应体系, 本文得到的反应截面与实验结果及准经典轨迹理论的计算结果符合得很好。

TRANSITION STATE THEORY CALCULATIONS ON SELECTED-STATE REACTION CROSS SECTIONS OF H+O2(n0, j0)→HO+O AND C+H2(n0,J0)→CH+H

In this paper the reaction cross sections of H+O_2(n_0j_o)→HO+O and C+H_2(n_0j_0)→NCH+H systems with long-lived complex on their ab initio potential energy sur- faces were calculated using Marcus′ Microcanonical Transition State Theory. Ef- fects of the properties of potential energy surfaces on the reaction cross sections were discussed. We found that the reaction cross sections of the two systems first increase and then decrease as collision energy increases at given vibrational-rota-tional quantum number (n_0j_0), except n_0=0 and j_0=1; the reaction cross sections of the two reactions are all increased obviously with increase of n_0 at given collision energy and internal rotational state j_0; the variation of the reaction cross sections is complicated with increase of j_0 for H+O_2 system, and monotonous for the C+H_2 system except j_0=1. These calculated results of the reaction H+O_2(n_0j_0)→HO+O are in good argreement with that obtained by Quasiclassical Trajectory Theory and the experimental measurement.