分子束技术研究Ba与CHCl_3,CCl_4的反应

The Studies on the Reaction of Ba with CHCl_3, CCl_4 by Molecular Beam Techniques

本文分别在交叉分子束和分子束-气体条件下,利用化学发光方法,研究了Ba(~3D)+CH_2Cl_2,CHCl_3,CCl_4和Ca(~1S_0),Ca(~3P),Ba(1S_0),Ba(~3D)+CCl_4的反应。实验得出了Ba(~3D)与CH_2Cl_2,CHCl_3,CCl_4反应时,A^2Ⅱ,B^2Σ^+态BaCl产物的发光截面对反应物碰撞能的依赖关系和反应阈能,以及Ba(~3D)与CCl_4反应时,产生电子激发态BaCl产物的光子产率。发现当Ba,Ca被激发到亚稳态时,Ba+CCl_4的反应电子基态BaCl产物的振动激发增加;而Ca+CCl_4的反应电子基态CaCl产物的转动激发增加。并针对以上结果进行分析讨论。

On a crossed beam apparatus and on a beam-gas apparatus, the reactions Ba (~3D) +CCl_4, CHCl_3 and the reactions Ca(~1S_0), Ca(~3P), Ba(~1S_0), Ba(~3D)+CCl_4 have been studied by means of chemiluminescence (CL) and laser induced fluorescence (LIF), respectively. The plot of the CL cross sections of producing BaCl (A^2Ⅱ, B^2∑^+) from the reactions Ba (~3D)+CHCl_3, CCl_4 versus collision energy were obtained. It has been shown that the plot for the reaction Ba(~3D)+CCl_4 can be described by LOC model, and the plot for the reaction Ba (~3D)+CHCl_3 can be described by rigid nonspherical molecules, developed by Evans and Bernstein et al. The LIF study shows that for the reactions of Ca (~1S_0), Ca(~3p) with CCl_4, the change of Ca (~1S_0) to Ca(~3P) brought about an increase of the ground state CaCl product rotation energy; but for the reactions Ba(~1S_0), Ba(~3D)+CCl_4, the change of Ba (~1S_0) to Ba(~3D) brought about an increase of the ground state BaCl product vibration energy, which can be explained by the 'Impulse model of the atom-molecule reaction'.