甲基肼自由基在高温燃烧分解反应下的非谐振效应

摘要

In this work,the harmonic and anharmonic rate constants of the decomposition reaction of monomethylhydrazine (MMH) radicals have been calculated by using transition state (TS) and Rice-Ramsperger-Kassel-Marcus (RRKM) theories with either MP2 or B3LYP method at 6-311++G(3df,2p) basis set,respectively.The reaction mechanism and anharmonic effect of the MMH radicals are studied in detail and both of the harmonic and anharmonic rate constants increase sharply with increasing temperature in the canonical system.In the microcanonical system,these constants also show sharp increase with the energies.Overall,the anharmonic effect becomes more pronounced with the increasing temperature or energy in the canonical and microcanonical systems,respectively.These results indicate that the anharmonic effect of the decomposition reaction of MMH radicals is quite significant and cannot be ignored.%基于过渡态理论(TST)和RRKM (Rice-Ramsperger-Kassel-Marcus)理论,使用MP2/6-311++G (3df,2p)//B3LYP/6-311++G(3df,2p)基组和方法,本文分别计算了甲基肼自由基在高温燃烧下分解反应的谐振以及非谐振速率常数.因此,甲基肼自由基的详细机理得以研究.在正则系综中,谐振以及非谐振速率常数都随着温度的升高而增加;而在微正则系综中,速率常数随着能量的升高而增加.整体上看,在正则系综和微正则系综中,非谐振效应分别随着温度和能量的升高而变得越来越明显.因此甲基肼自由基在高温燃烧下分解反应的非谐振效应是不能被忽视的.