Obtaining clear molecular-level descriptions of the hydrated proton and hydrated electron represent two of the fundamental issues in modern-day physical chemistry. Bulk-phase spectral signatures of these species yield broad, continuous absorptions throughout the water bending and stretching regions, thereby making it difficult to identify precisely the accommodation motifs surrounding the excess charge defect. To circumvent this problem, small-water cluster analogs to the larger bulk-phase phenomena have been investigated. In the case of the hydrated proton, distinct spectral features associated with two different proton incorporation classes, the H3O+ "Eigen" and H3O2+ "Zundel" ion cores, are observed. The evolution of these motifs is monitored as a function of cluster size and it is observed that subtle changes to the hydration environment can result in extreme spectral shifts of the proton signature. In the case of the hydrated electron, cluster data reveal that the excess electron is bound to the surface of the neutral water core via a single water molecule. The infrared spectral signature of this unique water is distinct and reveals that it is attached to the water network through a double H-bond acceptor motif. It is observed that this spectral feature is quite robust and persists into larger water clusters containing upwards of 50 molecules!
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机译：对水合质子和水合电子获得清晰的分子水平描述是现代物理化学中的两个基本问题。这些物质的体相光谱特征在整个水弯曲和伸展区域产生宽广的连续吸收，从而使得难以精确识别围绕过量电荷缺陷的调节基序。为了解决这个问题，已经研究了与大体积相现象相似的小水团簇类似物。在水合质子的情况下，观察到与两种不同质子掺入类别H 3 O +“本征”和H 3 O 2 +“ Zundel”离子核相关的明显光谱特征。监测这些基序的演变是簇大小的函数，并且观察到水合环境的细微变化会导致质子签名的极端光谱偏移。对于水合电子，簇数据表明，多余的电子通过一个水分子与中性水核的表面结合。这种独特的水的红外光谱特征很明显，表明它通过双H键受体基序与水网络相连。可以观察到，该光谱特征非常强大，并持续存在于包含50个以上分子的较大水簇中！
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