中文摘要：

臭氧是影响平流层辐射、化学等过程的关键成分，在气候和环境变化中扮演着非常重要的角色．臭氧层的损坏对人类的生存造成了很大的威胁，近年来，臭氧的损耗问题已引起了人们的广泛关注．氟里昂和哈龙等含氯和溴的化合物是导致臭氧层耗损的主要物种，对其替代物的研究是当前热门课题

英文摘要：

The hydrogen abstraction reactions by ozone from fluoromethanes（CH3F, CH2F2 are the most suitable processes for modeling and testing methodologies that could be applied to larger molecules or to the complete reaction kinetic schemes for the degradation of HFCs. We presented a theoretical study of the hydrogen abstraction reactions from CH3F and CH2F2 by ozone molecule. The geometries, harmonic vibrational frequencies of all stationary points were calculated at MPW1 K level of the theory. The energies of all the stationary points were refined by using higher-level（denoted as HL） energy calculations. The minimum energy paths （MEPs） were obtained by the MPW1 K/6-31 ＋ G （d,p） level. Energetic information of the points along the MEPs is further refined by HL method. The rate constants were evaluated on the basis of the MEPs from the HL level of theory in the temperature range of 200-2500 K with the conventional transition state theory （TST）, the canonical variational transition state theory （CVT） and the microcanonical variational transition state theory（μVT） based on the ab initio calculations. A general agreement was found among the TST, CVT, and μVT theories. The fitted three-parameter Arrhenius expressions of the calculated forward CVT/SCT, and μVT/Eckart rate constants of the ozonolysis of fluoromethane are k^CVT/SCT （T） - 2.76 × 10^-34 T^5. 81 e（ -13975/T） and k^μVT/Eekart （T） ： 1.15 × 10^-34 T 5.97 e ^（ - 14530.7/T）, respectively. The fitted three-parameter Arrhenius expres- sions of the calculated forward CVT/SCT, and μVT/Eckart rate constants of the ozonolysis of difluoromethane are k^CVT/SCT（T） = 2.29 × 10^-36 T^6.42 e^（-15451.6/T） and k^μVT/Eckart （T） = 1. 31 × 10^-36 T 6.45 e^（ -15465.8 /T） , respectively.