基态和亚稳态的Ca、Ba原子与ClO2化学发光反应的动态学研究

在束-气装置上的单次碰撞条件下, 利用低压直流放电选择性地激发碱土金属到亚稳态, 观察了Ca(~1S)、Ca(~1S’~3P)、Ba(~1S)、Ba(~1S, ~3D)+ClO_2。反应的化学发光. 通过测量化学发光总包光强的空间分布, 得到这些反应的总碰撞截面为: Ca(~1S)+ClO_2, 0.97 nm; Ca(~3P)+ClO_2, 1.38 nm; Ba(~1S)+ClO_2, 13.6 nm; Ba(~3D)+ClO_2, 2.39 nm, 计算机模拟化学发光光谱, 发现新生产物MO(M=Ca, Ba)的电子激发态A~1П态的相对振动布居分布是非玻尔兹曼分布的, 求出反应Ba(~3D)+ClO_2和Ca(~3P)+ClO_2产生的MClC~П→X~2 ∑~+跃迁的化学发光截面分别为0.51 nm和0.31 nm, 计算光谱中不同成份的光强, 得到了反应产生MO、MCl的产物分支比. 最后, 讨论了这类反应的机理。

Dynamics Studies of the Chemiluminescent Reactions of ClO2 with Ca(1S,3P) and Ba((1S,3D)

The chemiluminescent reactions of ClO_2 with Ca, Ba atoms have been studied under single collision condition in a beam-gas apparatus. The metastable states of the metal atoms are generated by the use of low valtage DC discharge. The Chemilu-minescence spectra have been observed and the spatial distributions of the intensities of the chemiluminescent emissions have been also measured by OMA-Ⅱ. The total reaction cross sections of metal atoms measured are 0.97 nm, 1.38 nm for Ca(~1S), Ca(~3P) and 1.36 nm, 2.39 nm for Ba(~1S), Ba(~3D) respectively. The intensities of the chemilu-minescence spectra are increased significantly when the metal atoms are excited to their metastable states. In particular, the increase of BaO(A′) is much more than that of BaCl(C) in the reaction of Ba(~3D)+ClO_2. In addition, non-Boltzmann vibrational distributions were found in the electronic excited state A′~1П of the products MO in both reactions by computer simulation. The chemiluminescent cross sections of the transition C~2П→X~2∑~+ of the products MCl are 0.51 nm for Ba(~3D)+ClO_2, 0.31 nm for Ca(~3P)+ClO_2 respectively. The branching ratios of the products MO and MCl were calculated based on the chemiluminescent spectra. A discussion about the mechanisms of these reactions is presented.