Inhomogeneous dynamics in confined water nanodroplets
Inhomogeneous dynamics in confined water nanodroplets
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DOI：
10.1073/pnas.0603239103
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发表时间：
2006-10-17
影响因子：
11.1
通讯作者：
Bakker, Huib J.
中科院分区：
文献类型：
--
作者：
Dokter, Adriaan M.;Woutersen, Sander;Bakker, Huib J.
利用中红外超快泵浦探测光谱研究了约束对反胶束HDO:D2O中液态水动力学性质的影响。通过制备不同粒径的反胶束，我们改变了半径为0.2 ~ 4.5 nm的纳米水滴的几何约束程度。我们发现位于液滴交界面附近的水分子表现出较慢的振动能量弛豫，并且与位于液滴核心的水分子具有不同的光谱吸收。因此，我们可以高选择性地测量这些不同类型的水的取向动力学。我们观察到核心区的水分子表现出与体积水相似的取向动力学，并且溶化界面的水层具有高度的不动性。
The effect of confinement on the dynamical properties of liquid water was studied by mid-infrared ultrafast pump-probe spectroscopy on HDO:D2O in reverse micelles. By preparing water-containing reverse micelles of different well defined sizes, we varied the degree of geometric confinement in water nanodroplets with radii ranging from 0.2 to 4.5 nm. We find that water molecules located near the interface confining the droplet exhibit slower vibrational energy relaxation and have a different spectral absorption than those located in the droplet core. As a result, we can measure the orientational dynamics of these different types of water with high selectivity. We observe that the water molecules in the core show similar orientational dynamics as bulk water and that the water layer solvating the interface is highly immobile.