Penning Ionization by Collisions of Metastable Atoms with van der Waals Clusters

首先，用交叉束法和荧光光谱相结合的方法，研究了150 MeV下亚稳态氦原子碰撞产生的线性三原子分子(二氧化碳、羰基硫化物、二硫化碳、一氧化二氮)、六氟苯和五氟苯的潘宁电离。测定了电子激发母离子的发射截面及其振动分布，并与流动余辉和光致电离得到的数据进行了比较。基于He^&lt；**&gt；束源发射截面与放电功率的依赖关系，研究了He^-lt；**&gt；与靶分子之间的相互作用。其次，研究了He^-lt；**&gt；碰撞引起的CCl_4、CHCl_3、CFC_3、CF_2Cl_2和CBrC_3的离解电离。测定了几个中性碎片的发射截面。这些碎片的发射截面与碰撞能量无关。这一结果更倾向于鱼叉机制。有关这些结果的论文已提交给化学。太棒了。和J.Phys。化学。为了更定量地讨论He^-lt；**-gt；与靶分子之间的相互作用势，正在对发射截面的碰撞能量依赖性进行更详细的研究。

First, penning ionizations of linear triatomic molecules (carbon dioxide, carbonyl sulfide, carbon disulfide, nitrous oxide), hexafluorobenzene, and pentafluorobenzene resulting from collisions of metastable helium atom(He^<**>) have been studied at 150 meV by combining the crossed-beam method with fluorescence spectroscopy. Emission cross sections for electronically excited parent ions and their vibrational distributions are determined and compared with the data obtaind by flowing afterglow and photoionization. The interactions between He^<**> and target molecules were examined on the basis of the dependences of emission cross sections upon the discharge power applied to the He^<**> beam source.Second, dissociative ionizations of CC1_4, CHC1_3, CFC1_3, CF_2C1_2, and CBrC1_3 by collisions of He^<**> are studied. Emission cross sections for several neutral fragments have been determined. Emission cross sections for these fragments are independent of the collision energy. This results prefers the harpoon mechanism.Papers concerning these results have been submitted to Chem. Phys. and J.Phys. Chem. More detailed studies of the collision-energy dependence of emission cross sections are being carried out in order to discuss more quantitatively the interaction potential between He^<**> and target molecules.