大气压电晕放电离子迁移谱测量溴代烷烃的电子吸附速率常数

Rate constants of electron attachment to brominated methanes measured by corona discharge ion mobility spectrometry

常温大气压下,在电子能量为0.35~0.65 eV的范围内,使用氮气负电晕放电-电子吸附-离子迁移谱,测量了CH_2Br_2,CH_2BrCl,CHBr_3的电子吸附速率常数,得到电子吸附速率常数的大小关系为k(CH_2Br_2)>k(CH_2BrCl),k(CH_2Br_2)>k(CHBr_3),并根据电子亲和势对CH_2Br_2和CH_2BrCl的大小关系进行理论分析。首次对CHBr_3的电子吸附过程进行了定性分析,发现样品蒸汽在迁移区通入迁移管时,溴离子会与CHBr_3分子络合成团簇离子Br^-(H_2O)_n(CHBr_3)_m。

Using atmospheric pressure nitrogen negative corona discharge electron attachment ion mobil- ity spectrometry, the rate constants of electron attachment to CH2Br2, CH2BrC1 and CHBrs were mea- sured at ambient temperature as a function of average electron energy in the range from 0.35 eV to 0.65 eV. The rate constants for electron attachment to CH2Br2, CH2BrC1, CHBr3 follow the relations of k（CI-I2Br2）〉k（CH2BrC1）, k（CH2Br2）〉k（CHBr3）, and the relations between CH2Br2 and CH2BrC1 are discussed in theory according to the electron affinity. In addition, the process of electron attachment toCHBr3 is firstly qualitative analyzed. It＇s found that when the sample vapor is introduced into the drift region, the bromine ion will cluster with the molecule of CHBr3 to be Br-（H20）n （CHBr3）m.