摘要
用四倍频ＹＡＧ激光（２６６ｎｍ）光解ＣＨＢｒ_３产生ＣＨ（Ｂ~２Σ~－）自由基，通过测量自发辐射ＣＨ（Ｂ→Ｘ）的时间分辨信号测得室温下ＣＨ（Ｂ）被卤代甲烷、ＣＳ_２、Ｏ_２及Ａｒ的猝灭速率常数（×１０^（－１０）ｃｍ~３·ｍｏｌｅｃ^（－１）·ｓ^（－１））分别为４．４±０．７（ＣＨ_２Ｃｌ_２）、５．２±０．４（ＣＨＣｌ_３）、５．０±０．７（ＣＣｌ_４）、８．２±０．３（ＣＨＢｒ_３）、７．９±０．７（ＣＳ_２）、０．１９±０．０２（Ｏ_２）及（１．１±０．１）×１０^（－２）（Ａｒ）．结果表明，除Ｏ_２外，其它猝灭剂对ＣＨ（Ｂ）的猝灭速率常数均大于对ＣＨ（Ａ）的。对卤代甲烷分子，猝灭速率常数显示了因Ｃｌ原子数增加而增加的趋势。
CH(B￣2Σ￣(-))radical was produced by quadrupuled YAG laser(266 nm)photolysis of CHBr_3 molecules.The quenching rate constants by halomethane(CH_2Cl_2,CHCl_3,CCl_4 and CHBr_3),CS_2,O_2,and Ar were determined at room temperature by monitoring the time-resolved emission CH(B→X)signals.The measured results(in 10￣(-10)cm￣3·molec￣(-1)·s￣(-1))are 4.4±0.7(CH_2Cl2),5.2±0.4(CHCl_3),5.0±0.7(CCl_4),8.2±0.3(CHBr_3),7. 9±0.7(CS_2),0.19±0.02(O_2),and(1.1±0.1)×10￣(-2)(Ar),respectively。It is shown that the quenching rate constant of CH(B)is faster than that of CH(A)except for O_2 molecule.The quenching rate constant of CH(B)increases with increasing the number of chlorine atoms contained in chloromethane molecules and an interpretation of this result based on complex model is presented.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1994年第10期1525-1528,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
