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氟氯甲烷CC1_4,CFC1_3,CF_2C1_2,CF_3C1及CF_4的量
引用本文:吕庆章,李工安. 氟氯甲烷CC1_4,CFC1_3,CF_2C1_2,CF_3C1及CF_4的量[J]. 河南师范大学学报(自然科学版), 1996, 0(1)
作者姓名:吕庆章  李工安
作者单位:河南师范大学化学系
摘    要:本文用量子化学从头计算法在HF/4-31G水平上对氟氯甲烷(CFCmn)分子作了计算,从分子结构参数及前沿分子轨道组合上做了详细分析。说明了随着F原子取代CC14中C1原子的增多,分子的各化学健均增强,稳定性增加,HOMO能级降低,LUMO能级升高;HOMO对C-F和C-C1键都无甚键合作用,LUMO对C-C1起反键作用,当HOMO上电子被激发到LUMO上时,分子发生解离。造成大气平流层臭氧消耗的分子光解出来的C1原子,εLUMO与εHOMO差值越大,光解需要的紫外光波长越短,发生光解时在大气中的高度越高,大气滞留时间越长,解离出的C1原子消耗的臭氧分子越多。

关 键 词:CFCs;平流层臭氧;量子化学计算

The Study of Chlorofluoromethanes CCl_4 CFCl_3, CF_2Cl_2,CF_3Cl and CF_4 by Quantum Chemistry Method
Lu Qingzhang,Li Gong''''an. The Study of Chlorofluoromethanes CCl_4 CFCl_3, CF_2Cl_2,CF_3Cl and CF_4 by Quantum Chemistry Method[J]. Journal of Henan Normal University(Natural Science), 1996, 0(1)
Authors:Lu Qingzhang  Li Gong''''an
Abstract:Chlorofluoromethanes were calculated by quantum chemistry abinitiomethod. Molecular structure parameters and HOMO's and LUMO's constitution were analysed. As fluorine atom replaces chlorine atom in CCl4 one by one, the bonds in molecule are strengthened while the valueofεHomois decreased and the value of εLuMois increased. HOMO is unbonding to C-F and C-Cl bondsmeanwhile LUMO is intensively antibonding to C-Cl bonds except for antibonding to C-F bonds inCF4.The molecule will be dissociated when electron is excited from HOMO to LUMO. As a result,thechlorine given by photolysis taken place in stratosphere by molecular oboorbing short-wavelength solarUV radiation which causes electronic excitation from HOMO to LUMO causes ozone depletion.Thebigger the difference between εLUMO and εHOMO is, the higher the photolysis takes place in atmosphereand the longer the atmosphere lifetimes of chloronuoromethanes are.
Keywords:chlorofluoromethane  ozone-depletion  quantum chemistry calculation  
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