在束-气装置上研究Sr(1S),Sr(3P)+Cl2的化学发光反应动力学

本文在束-气条件下研究了Sr(~1S), Sr(~3P)+Cl_2的化学发光反应。实验压力为10~(-5)～10~(-4)Torr, 金属束炉温1000 K左右。同时, 观测和分析了Sr, Sr~*+Cl_2反应产物Sr(A,B)、SrCl_2~*的发光光谱。发现Cl_2压力(pcl_2)较低时, 主要生成SrCl~*; 而pcl_2增高时(>2×10~(-4)Torr), SrCl_2~*的发射光谱逐渐增强。实验结果表明, SrCl~*是单次碰撞的直接产物, 其发光强度(I_(SrCl)~*)与pcl_2、Sr的原子密度均为直线关系, 而I_(SrCl_2)~*与pCl_2成二次关系, 表明SrCl_2~*是SrCl~*和Cl_2碰撞的产物, 与BaCl_2~*的生成机理相同。由实验结果计算而得到的亚稳态Sr~*原子及基态Sr原子在Cl_2中的总消除截面分别为9.7±5 nm~2及5.8±5 nm~2。由此估计由亚稳态Sr~*及基态Sr与Cl_2反应生成SrCl(A)的相对光子产率为Φ~*/Φ~0=115。

BEAM-GAS CHEMILUMINESCENT REACTIONS OF Sr(1S) AND Sr(3P)+ Cl2

The CL reactions of Sr(~1S), Sr(~3P)+Cl_2 have been studied under single collision condition on a beam-gas apparatus in the pressure of range 10~(-5)—10~(-4) Torr.The temperature of the metal oven was about 1000 K. The CL spectra of SrCl (A,B) and SrCl_2~* produced in the reactions of Sr, Sr~* +Cl_2 have been observed and analyzed. The CL spectra are always dominated by the monochloride emission while the subcontinuous emission of dichloride SrCl_2~* becomes stronger with increasing Cl_2 pressure. The experimental results show that the intensity of SrCl~* emission depends linearly upon both Cl_2 pressure and Sr number density. This means that SrCl~* is the direct product of single collisions. Whereas the quadratic dependency of SrCl~*_2 intensity upon the Cl_2 pressure shows that it is produced in arreaction of SrCl+Cl_2, the same mechanism as BaCl~*_2 produced in reaction of Ba+Cl_2~(4,5]). The total cross section for the removal of metal atoms in ground state Sr(~1S) and excited states Sr(~3P) by Cl_2 molecules are 5.8 nm~2 and 9.7 nm~2 respectively. The relative photon yield of SrCl(nm) produced by Sr(~1S) and Sr(~3P) reacting with Cl_2 is about Φ~*/Φ~0=115.