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用量子化学从头计算UMP2 (full)方法研究F和Cl原子与甲烷分子和臭氧之间的反应机理 ,优化了反应物、产物、中间体和过渡态的几何构型 ,在Gaussian 3(G3)和G3MP2水平计算了它们的能量 .研究结果表明 :F原子与Cl原子一样与臭氧之间有很强的反应活性 ,而F原子与甲烷分子反应过程中有氢键生成 ,键能为 3.71kJ mol,F原子与甲烷分子之间反应活性比与臭氧分子之间反应活性强 .F原子易与甲烷分子生成含有氢键的化合物 ,且很快分解生成化学性质非常稳定的HF ,能同F +O3反应竞争 .而Cl原子甲烷分子反应过程中则无氢键生成现象 .且在Cl原子与臭氧和甲烷之间竞争反应时 ,Cl原子与臭氧之间反应优先 ,同时我们还对F和Cl原子与甲烷分子和臭氧之间反应动力学速率常数进行了计算 ,我们的理论计算结果能合理地解释大气中Cl原子是损耗臭氧的主要化学物质 ,而活性更强的F原子为什么对臭氧损耗较小的原因
Using quantum chemistry, UMP2 (full) method was used to study the reaction mechanism between F and Cl atoms and methane molecules and ozone. The geometrical configurations of reactants, products, intermediates and transition states were optimized. In Gaussian 3 (G3) and G3MP2 have been calculated.The results show that the F atom has strong reactivity with Cl atom and ozone, while the F atom and methane molecule have hydrogen bond during the reaction, the bond energy is 3.71 kJ mol, The reactivity between F atoms and methane molecules is stronger than that between ozone molecules and ozone molecules, and F atoms easily form compounds containing hydrogen bonds with methane molecules and quickly decompose to form HF with very stable chemical properties and react with F + O 3 While Cl atom has no hydrogen bond during methane molecule reaction.When the Cl atom competes with ozone and methane, the reaction between Cl atom and ozone is prioritized. At the same time, we also study the relationship between F and Cl atoms and methane The reaction kinetic rate constants between molecules and ozone were calculated. Our theoretical calculations can reasonably explain that Cl atoms are the main ozone-depleting chemicals in the atmosphere, while the more active F atoms are What causes less ozone depletion