A Study of Reaction and Scattering of Alkali-earth Metals by Using Crossed Molecular Beams.

本研究的目的是发展一种新的方法，测量气束反应和交叉束反应中碱土化合物分子生成截面随反应物和反应物分子能量的变化。这些分子是激光研究反应动力学的良好候选者。1）研究了Ar与亚稳Ca ^3 P态的交叉束，测量了Ca ^3 P态精细结构能级间的能量转移截面。用泵浦激光从一定J能级上抽运出所有原子，用探针激光测量Ar束碰撞的再布居程度，确定能量转移截面。2）测量了I_2- He超声分子束的能级间振转能量转移率。测量了激光直接诱导的荧光强度和能量转移能级的间接荧光强度随激发位置和观测位置的变化，并通过对观测光谱的轮廓分析，确定了能级间弛豫速率。3）温度和压力沿着射流膨胀方向变化剧烈，约为三个数量级。我们建议用这个系统来研究反应截面的能量依赖性。我们建立了一个放电自由膨胀射流装置，并对许多自由基物种进行了光谱观察。在此基础上，研制了一套用于反应动力学研究的空间分辨光谱测量系统。4）采用可调谐度为30 nm的半导体激光器，研制了一套用于反应研究中状态分析和原子束探测的半导体激光探针系统。

The purposes of this study are to develop new method and to measure the cross-section for the formation of alkali-earth compound molecules in gas-beam reaction and cross-beam reaction as a function of the energies of the reagent and reactant molecules. These molecules are fortunately good candidates for the laser study of reaction dynamics.1) The cross-beam of Ar and metastable Ca in ^3P state was studied to meseasure the cross-section for energy transfer between fine-structure levels of Ca ^3P state. A pumping laser puped out all atoms form a certain J level and the degree of repopulation by collision of Ar beam was meseasured by a probe laser to determine the cross-section for energy transfer.2) We have measured the level to level vibrational-rotational energy transfer rate in I_2- He supersonic molecular beam. The intensities of fluorescence induced directly by laser and indirect fluorescence from the energy transfered levels were measured as function of exciting position and observing position along molecular beam and the rates for the level to level relaxation were determined from contour analysis of the observed spectra.3) The temperature and the pressure are varying drastically, say three orders in magnitude, along the expanding jet. We have proposed that we should use this system to study the energy dependence of reaction cross-section. We have constructed a discahrage free expansion jet aparatus and many radical species were spectroscopically observed. We have developed a measurement system for spacially resolved spectroscopy to strudy reaction dynamics in this system.4) Diode laser probe system for state analysis in reaction study and suitable for detection of atomic beam has been developed by using diode laser of which tunability was 30 mn.