摘要
大气臭氧层的破坏近年来受到人类越来越多的关注，ClO自由基在臭氧催化循环中有重要作用，科学研究表明：一个氯原子可以破坏高达10~5个O_3分子，因此研究ClO与其它自由基的反应对于了解臭氧层的破坏具有重要的现实意义。本论文以ClO与ClO、BrO、IO自由基反应机理为研究对象，以期通过量子化学方法详细研究以上三个反应的反应机理，优化得到新的异构体构型，发现新的反应途径，并从量子拓扑学的角度，对各反应通道关键点进行分析，从微观上讨论反应过程中化学键的断裂、生成以及键的变化规律，为进一步的理论和实验研究提供依据。
在论文开展之初，对该类反应研究现状进行了文献调研。1985年，人们第一次观察到在南极上空臭氧层遭到了严重破坏，认为是包括ClO在内的接触反应的结果，八十年代末和九十年代，人们进行了大量的实验与理论研究，包括该类反应所形成的中间体的热动力学稳定性、红外和紫外交叉吸收、光解反应以及部分异构体的转化等，但对XO(X=Cl、Br、I)相互反应的机理研究并不全面和深入。本论文的第二章、第三章、第四章分别研究了ClO与ClO、BrO、IO反应机理，并进行了电子密度拓扑分析。
主要结论概括如下：
(1) 研究了ClO与ClO的反应机理，找到了Cl_2O_2的5种异构体构型，其中OClClO构型为首次报导，振动分析确认了该构型为稳定构型，IRC计算确认了五种异构体之间的相互转化关系，纠正了前人找到的ClOOCl与ClClOO之间错误的过渡态。找到了ClO与ClO反应可能的8个反应通道，合理的解释了三线态氧气的产生机理，从电子密度拓扑学的角度分析了异构化及离解过程中化学键的断裂及键的变化规律，
ClOClO→ClOOCl,ClOClO→ClClO_2及ClOOCl→ClClOO反应过程中各存在一个三元环结构过渡态，ClOOCl→OClClO、ClOOCl→Cl_2+~1O_2及ClOOCl→Cl_2+~3O_2反应过程中各存在一个四元环结构过渡态，以上结构过渡态与能量过渡态的相对位置都与本实验组提出的“吸热反应结构过渡态出现在能量过渡态之前，放热反应出现在能量过渡态之后”的结论一致。
(2) 研究了ClO与BrO的反应机理，优化得到了BrClO_2的5种异构体构型，其中BrClOO及OBrClO构型为首次报道，振动分析确认了以上两个构型为稳定构型，IRC计算确定了五种异构体之间的相互转化关系。找到了ClO与BrO反应可能的8个反应通道，纠正了文献报道的BrOOCl与BrClO_2之间存在过渡态的错误。从电子密度拓扑学的角度分析了异构化及分解过程中化学键的断裂及键的变化规律，再次证明了我们所提出的有关不同热效应中结构过渡态超前和滞后于能量过渡态的结论的正确性。
CIO一与XO反应机理及电了密度拓扑分析
(3)研究了CIO与10的反应机理，优化得到了ICIO:的七种异构体构型，他们
的稳定性顺序与BrcloZ不同)其中CllOZ构型最稳定，IC10O构型最不稳
定，IRC计算确认了七种异构体之间的相互转化关系。找到了CIO与10反
应可能的10个反应通道，能够产生I原子的反应通道比较容易发生，与实
验结果保持一致。从电子密度拓扑学的角度分析了异构化及离解过程中化
学键的断裂及键的变化规律，再次证明了我们所提出的有关不同热效应反
应中结构过渡态超前和滞后与能量过渡态的结论的正确性。
本论文的创新之处在于:
(1)优化得到了一类新的异构体OXCIO(X=Cl、Br、I)，振动分析确认了该类
异构体为稳定构型。纠正了前人找到的CIOOCI与CICIOO之间互相转化的
错误的过渡态，找到了他们之间互相转化的合理的过渡态。纠正了文献报
道的BrQOCI与BrCIO:之间可以互相转化的错误。
(2)对xo(X二Cl、Br、J)相互反应机理进行了全面深入的研究，发现了新的反
应通道，找到了该类反应的异同点。
(3)从量子拓扑学的角度，对各反应通道关键点进行了分析，从微观上讨论了
反应过程中化学键的断裂、生成以及键的变化规律，找到了各反应过程的
能量过渡态和结构过渡态。
The gas-phase chemistry of halogen monoxide radicals has long been of atmospheric interest, because of their direct involvement in several catalytic ozone depletion cycles. The object of this work is the mechanism of ClO with C1O BrO and 10 radical reaction, the purpose of this work is to study the intermediate geometry configurations and the possible reaction path and provide the help for the experiment. The characters of the major critical points have been disscussed by topological ananlysis of the electronic density, and the chemical bonds have been disscussed, the energy transition states and structure transition states have been found.
In the first part of this work, previous studies on ClO with ClO BrO IO radical reaction were surveyed. In the end of eighty years and ninety years, the people have done a plenty of theoretic and experimental research, but the mechanism of the kind of reaction is short of detailed research.
In chapter II III IV. the mechanism of ClO with ClO BrOl IO radical reaction is studied. The main conclusions are listed as following:
(1) The mechanism of ClO with ClO reaction is studied, five isomer configurations of Cl2O2 are found , 0C1C10 configuration is reported firstly and the frequency is calculated, IRC calculations have also been processed ,the different transition state with reference is found about C100C1 with C1C100. The possible eitht paths are found, the product of triplet oxygen is resonably explained, The characters of the major critical points have been disscussed by topological ananlysis of the electronic density, and the chemical bonds have been disscussed, the energy transition states and structure transition states have been found.
(2) The mechanism of ClO with BrO reaction is studied, and five isomer configurations
of BrClO2 are found, the geometry configuration of BrClOO and BrOClO is firstly reported, their frequency is calculated, IRC calculation about five isomers is processed, the possible eight paths are found, the error about the translation of BrOOCl and BrClO2 is corrected, The characters of the major critical points have been discussed by topological analysis of the electronic density, and the chemical bonds have been discussed, the energy transition states and structure transition states have been found.
(3) The mechanism of ClO with IO reaction is studied, the seven isomer geometry
configurations are found, and their stable order is different with BrC102, the most stable geometry configuration is ClIO2, and the most unstable geometry
configuration is IC100, IRC calculation is processed, the possible ten paths are found, the path which can produce iodine easily process, which is consist with experimental result, the characters of the major critical points have been discussed by topological analysisof the electronic density, and the chemical bonds have been discussed, the energy transition states and structure transition states have been found. The new conclusion and ideas of this work are listed as following:
(1) The new geometry configurations OXClO(X=Cl Br I) are found ,their frequency and IRC calculation are processed, the errors in reference are corrected .
(2) ClO with ClO BrO IO reaction are detailed studied, and the new paths are found, and their similar and different points are found.
(3) The characters of the major critical points have been discussed by topological analysis of the electronic density, and the chemical bonds have been discussed, the energy transition states and structure transition states have been found.
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