Rotational-state resolved quantum dynamics of molecular anions in a low temperature ion trap

我们将研究负离子的冷反应动力学，特别强调基元反应过程中量子态的特定效应。这项研究的动机是我们最近的突破，定量测量电子脱离分子阴离子在低旋转温度和观察一个意想不到的温度依赖性的反应速率系数，指示一个未知的能量障碍，为负离子反应的温度下降到8开尔文。我们的目标是确定量子力学效应在负离子反应中的普遍重要性，并研究量子效应如何在较大的分子和微溶剂化分子簇中被修改。这些实验采用了多极离子阱，这使我们能够控制内部温度的缓冲气体冷却被困离子。我们将专门研究作为旋转和平移温度的函数的绝对光剥离和化学反应截面。这些结果将提供洞察的相关性量子态的具体影响的负离子在大气和星际环境中的反应。特别是，我们将确定合适的候选人的负离子，承诺在星际分子云可观察到的。

We will investigate cold reaction dynamics of negative ions with specific emphasis on quantum state-specific effects in elementary reaction processes. This research is motivated by our recent breakthroughs of quantitatively measuring electron detachment from molecular anions at low rotational temperature and of observing an unexpected temperature-dependence of the reaction rate coefficient, indicative of an unknown energy barrier, for a negative ion reaction for temperatures down to 8 Kelvin. Our goal is to identify the general importance of quantum mechanical effects in negative ion reactions and to investigate how quantum effects are modified in larger molecules and in microsolvated molecular clusters. These experiments employ a multipole ion trap, which allows us to control the internal temperature of trapped ions by buffer gas cooling. We will specifically study absolute photodetachment and chemical reaction cross sections as a function of the rotational and translational temperature. These results will provide insight into the relevance of quantum-state specific effects for reactions of negative ions in atmospheric and interstellar environments. In particular, we will identify suitable candidates of negative ions that promise to be observable in interstellar molecular clouds.