Photoelectron spectroscopy of large water cluster anions and related systems

虽然水合电子在近50年前就被发现了，但它的确切性质仍然存在争议。原因在于自陷效应的复杂性，它涉及到电子与水相互作用的细节，以及水本身的结构。原则上，水簇阴离子是解决这些问题的理想模型系统，因为它们允许覆盖从仍然可以通过高水平计算处理的小尺寸到大的几乎大块的尺寸的全尺寸范围。对于非常小的团簇（少于10个分子），理论和实验之间的一致性已经达到了令人印象深刻的高水平。然而，对于较大的团簇，情况并非如此;既不知道所观察到的团簇的几种结构形式的确切性质，也不知道将结果正确地外推到大块。在实验方面，这是由于现有测量的技术缺陷，如有限的尺寸范围或缺乏精确的温度控制。使用新一代的簇光谱设置，我们计划进行温度控制的水簇阴离子和相关系统在一个非常广泛的尺寸范围内的光电子能谱。预计这些结果将大大提高对水分子团簇中过量电子的理解，并最终澄清这些性质如何收敛到大体积。

Although the hydrated electron has been discovered almost 50 years ago, its exact nature is still under debate. The reason lies in the complexity of the self-trapping effect, which reaches from details of the electron-water interaction to the structure of water itself. Water cluster anions are in principle ideal model systems to tackle these questions, as they allow to cover the full size range from small sizes, which are still treatable by high level calculations, to large, practically bulk-like sizes. For very small clusters (with less than 10 molecules) the agreement between theory and experiment has reached an impressively high level. This is not the case for larger clusters, though; neither the exact nature of the several structural forms of the clusters observed nor the correct extrapolation of the results to the bulk is known. On the experimental side, this is due to technical shortcomings of the existing measurements, like limited size range or lack of precise temperature control. Using a new generation cluster spectroscopy setup we plan to perform photoelectron spectroscopy on temperature controlled water cluster anions and related systems in a very broad size range. The results are expected to substantially improve the understanding of excess electrons in water clusters, and to finally clarify how these properties converge to the bulk.