CH_2X(X=H,FCI)与臭氧反应机理的最子化学研究

用量化学UMP2方法，在6-311++G**基组水平上研究了CH_2X(X=H,FCI)与臭氧反 应机理，全参数优化了反应过程中反应物、中间体、过渡态和产物的内何构型，在 UQCISD（T）/6-311++G**水平上计算了它们的能量，并对它们进行了振动分析，以 确定中间体和过渡态的直实性。从CH_2X(X=H,FCI)与O_3的反应机理的研究结果看 ，它们与O_3反应的活性都比较强，相对而言，活性大小顺序为CH_2F＞CH_3＞ CH_2CI，也就是说，CH_2F自由基与臭氧间的反应活性最强，对大气臭氧的损耗将 是最大的。同时研究还发现CH_2X(X=H,FCI)系列自由基与O_3的反应都是强放热反 应。

Study on the Quantum Chemistry of CH_2X(X=H,F,CI) and O_3 Reaction Mechanism

Quantum chemistry UMP2 method was performed to stu dy the reaction mechanism of the reactions of CH 2X (X=H, F, Cl) with O 3. The g eometric configurations of reactants, intermediates, transition states and produ cts were optimized by UMP2 method at 6-311++G ** level and the energies o f stationary points along the pathways were calculated at UQCISD(t)/6-311++G ** level. Intermediates and transition states were confirmed by vibration an alysis. From the results of the reaction mechanism of the reactions of CH 2X (X =H, F, Cl) with O 3, one can see that they are active radicals depleting ozone and the order of activity is CH 2F>CH 3>CH 2Cl. That is to say, CH 2F is t he most active chemical of the three radicals depleting the ozone layer. It is a lso found that the reactions of CH 2X (X=H, F, Cl) with O 3 are strongly e xothermic.