Determination of chemical shape and the propensity rule on channel branching by active control of quantum state

提出了一种利用伪随机脉冲辉光放电产生准稳态光束的新技术。通过将该技术与定向分子束技术相结合，本文研究了Penning电离反应体系的立体动力学，以揭示各通道的分支倾向规律，用定向CH_（10）-反应器测定了Ar（^3P）+ CH_3Cl→Ar + CH_3Cl^+ + e^-反应在特定相对取向下电离截面与碰撞能的关系。3Cl束和飞行时间测量。在低碰撞能区，空间不透明度函数与相关分子轨道电子的空间分布有很好的相关性。另一方面，空间不透明度函数随碰撞能量的增加呈现出明显的振荡结构。这种碰撞能量依赖性与基于相互作用势的各向异性的倾向性规则截然不同。我们认为这种差异可以归因于Penning电离和中性解离之间产物分支的依赖竞争随碰撞能的变化而变化。此外，在取向角分辨截面的能量依赖性中揭示了显著的共振结构。共振型结构可以被解释为“核激发的Feshbach共振”，在形成振动激发里德堡态，导致竞争性解离出口通道。

A new technique for generating matastable beam was performed by using the pseudo-random pulsed glow discharge method. By using this technique combined with the oriented molecular beam technique, stereo-dynamics in the penning ionization was studied for some reaction systems in order to reveal the propensity rule on the branching into each channel.Collision energy dependence of the ionization cross section for the Ar(^3P) + CH_3Cl→Ar + CH_3Cl^+ + e^- reaction was determined under specific relative orientation using an oriented CH_3Cl beam and time-of-flight measurements. A good correlation between the steric opacity function and the spatial distribution of the electron for the relatedmolecular orbital is recognized at the low collision energy region. On the other hand, steric opacity functions give the remarkable oscillation structure as the collision energy increase. This collision energy dependence is extremely different from the propensity rule based on the anisotropy of the interaction potential. We propose that this discrepancy can be ascribed to the dependent competition of product branching between Penning ionization and neutral dissociation varies as collision energy. In addition, the remarkable resonance structure is revealed in the energy dependence of orientation angle-resolved cross section. The resonance-type structure could be interpreted as a "nuclear-excited Feshbach resonance" in the formation of vibrational excited Rydberg states leading to a competitive dissociative exit channel.