Ultrafast 2D IR spectroscopy of the excess proton in liquid water
Ultrafast 2D IR spectroscopy of the excess proton in liquid water
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DOI：
10.1126/science.aab3908
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发表时间：
2015-10-02
期刊：
影响因子：
56.9
通讯作者：
Tokmakoff, Andrei
中科院分区：
文献类型：
--
作者：
Thaemer, Martin;De Marco, Luigi;Tokmakoff, Andrei
尽管经过数十年的研究，用于容纳水中过量质子的结构以及它们相互转化的机制仍然难以捉摸。我们使用超快二维红外（2D IR）光谱研究盐酸水溶液中的质子。通过激发O-H伸缩振动并检测整个中红外区域的光谱响应，我们观察到了Zundel络合物[H（H2O）（2）]（+）两侧沃茨的伸缩振动和弯曲振动之间的相互作用，分别在3200和1760 cm（-1）处。从随时间变化的拉伸弯曲交叉峰，我们确定了这个复杂的480飞秒的寿命的下限。这些结果表明，Zundel配合物在水溶液中的质子转移的关键作用。
Despite decades of study, the structures adopted to accommodate an excess proton in water and the mechanism by which they interconvert remain elusive. We used ultrafast two-dimensional infrared (2D IR) spectroscopy to investigate protons in aqueous hydrochloric acid solutions. By exciting O-H stretching vibrations and detecting the spectral response throughout the mid-IR region, we observed the interaction between the stretching and bending vibrations characteristic of the flanking waters of the Zundel complex, [H(H2O)(2)](+), at 3200 and 1760 cm(-1), respectively. From time-dependent shifts of the stretch-bend cross peak, we determined a lower limit on the lifetime of this complex of 480 femtoseconds. These results suggest a key role for the Zundel complex in aqueous proton transfer.