离解反应速率常数中的方位因素

Steric Effects in Rate Constants for Bimolecular Dissociation

以碰撞理论为基础探讨了结构方位因素对离解反应速率常数的影响 ,建立了计及方位特征的离解反应模型 ,计算对比了热平衡假设下空气中几个典型的离解反应的Arrhenius图 .结果表明 ,在所选实例中 ,除了反应N2 +N和O2 +O外 ,考虑方位因素后确实能够更好地理论估算出反应速率常数 .

The steric effects for bimolecular dissociation were investigated via the collision theory, and a sterically dependent bimolecular dissociation model was established. In order to validate the developed model, the rate constants of typical reactions taken place in air under thermal equilibrium condition were then calculated based on the new model, and were compared with the results obtained by the classical collision theory, as well as the available experimental data. As shown by the Arrhenius plots presented in this paper that the new model would provide more accurate results than the classical collision theory, when compared with the experimental data. The plots also depict some exceptional cases in the reactions of N 2+N and O 2+O, where there are discrepancies among the theoretical and experimental data. These discrepancies are also discussed in the present paper.