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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。
The CH (B ~ 2Σ ~) radical was generated by photolysis of CHBr_3 with fourfold-frequency YAG laser (266nm). CH (B) was detected by the time-resolved signal of spontaneous emission CH (B → X) , The quenching rate constants of CS_2, O_2 and Ar (× 10 -10 cm -3 ·· -1 s -1) were 4.4 ± 0.7 (CH 2 Cl 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) and (1.1 ± 0.1) × 10 -2 (Ar). The results show that the quenching rate constants of CH (B) except quenching agent are all greater than those of CH (A). For the halomethane molecules, the quenching rate constant shows a tendency to increase due to an increase in the number of Cl atoms.