Laser spectroscopic study of formation of alkali-earth and He van der Waals molecules

碱土和范德华分子形成的激光光谱研究

基本信息

批准号：
17550008
负责人：
MORIWAKI Yoshiki
金额：
$ 2.3万
依托单位：
University of Toyama
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

1. Spectroscopic study of alkali-earth atom - He collision dynamics in low temperature(1) Formation of Mg^<*4>He_n exciplex in low temperatureWe have observed the formation of ^<*4>MgHe_n exciplexes by means of laser excitation of Mg into the 3s3p ^1P_1 state in low temperature He gas (5-30K). Emission spectra have been analyzed using a theoretical pair potential. Exciplexes grow in many three-body reactions within its lifetime in the electronic excited state. Finally up to ten He atoms are attached around to a Mg atom to form a Mg*He_<10>. We have also observed almost the same results for Mg_<-3>He collisions. In this research, we have shown that the Mg*Hen molecules are formed although attractive interaction energy between Mg and He is small.(2) Collision dynamics of Ba^<+>-HeWe have investigated the relaxation process of Ba+ in the 6p ^2P_<3/2> state in collision with He atoms using laser spectroscopic method. We have obtained the rate constants of the formation and dissociation of Ba+*He, and the fine structure changing collision of Ba+ and Ba+*He. The resonance like structure observed in the cross section of the formation of Ba+*He exciplex indicates the two-step Lindemann mechanism. We have also observed a peculiar increase in the cross section of the fine-structure changing collision at the low temperature. This indicates another channel of the fine-structure change opens in the low temperature.2. Fine-structure changing collision of alkali-earth ionWe have measured the fine-structure changing collision cross sections of alkali-earth ions at room temperature in collision with He, H_2 and D_2. We have found that cross sections for collisions with He atoms decrease exponentially with the fine-structure splitting, which can be explained by the Landau-Zener model of the adiabatic transition. In contrast to this, cross sections for hydrogen molecules are much enlarged due to resonance between the fine-structure splitting and the rotation of hydrogen molecule.

1. 低温下碱土原子-He碰撞动力学的光谱研究(1)低温下Mg^<*4>He_n激基复合物的形成我们通过激光激发观察到了^<*4>MgHe_n激基复合物的形成Mg在低温He气(5-30K)中转变为3s3p^1P_1状态。使用理论电对势对发射光谱进行了分析。激基复合物在其生命周期内以电子激发态在许多三体反应中生长。最后最多十个He原子附着在Mg原子周围形成Mg*He_<10>。我们还观察到 Mg_<-3>He 碰撞几乎相同的结果。在这项研究中，我们发现尽管Mg和He之间的吸引力相互作用能很小，但还是形成了Mg*Hen分子。(2)Ba^<+>-He的碰撞动力学我们研究了Ba+在6p ^中的弛豫过程。使用激光光谱法与 He 原子碰撞时的 2P_<3/2> 态。我们得到了Ba+*He的形成和解离的速率常数，以及Ba+和Ba+*He的精细结构改变碰撞的速率常数。在 Ba+*He 激基复合物形成的横截面中观察到的类共振结构表明了两步林德曼机制。我们还观察到低温下精细结构变化碰撞的横截面出现特殊增加。这表明低温下精细结构变化的另一个通道打开。 2．碱土离子的精细结构变化碰撞我们测量了碱土离子在室温下与He、H_2和D_2碰撞的精细结构变化碰撞截面。我们发现，与 He 原子碰撞的截面随着精细结构分裂呈指数减小，这可以用绝热转变的朗道-齐纳模型来解释。与此相反，由于精细结构分裂和氢分子旋转之间的共振，氢分子的横截面大大扩大。