Russina Margarita, Günther Gerrit, Farago Bela, Babcock Earl, Salhi Zahir, Ioffe Alexander, Mezei Ferenc
Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin, Germany.
Institute Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France.
J Phys Chem Lett. 2025 Jun 12;16(23):5835-5843. doi: 10.1021/acs.jpclett.5c00735. Epub 2025 Jun 4.
The investigation of cooperative dynamics in HO, visible in coherent neutron scattering, has been hindered until now due to the very small signal. Using neutron polarization analysis, we were able, for the first time, to directly measure the coherent neutron scattering signal in light water with unprecedented accuracy. The observed coherent signal is enhanced in the intermediate range of 0.2 to 1 Å, providing clear evidence that intermolecular interactions in water extend beyond the distances between nearest neighbors. Our study reveals the existence of a picosecond cooperative process in water, whose nature could be related to the cooperative rearrangements of several water molecules. This process may act as a precursor to large-scale transport related to viscosity. Our results help to improve the understanding of general transport mechanisms at the nanoscale, which can be useful for biomedical technologies or the development of nanofluidic devices.
由于信号非常微弱，此前对水（H₂O）中合作动力学的研究一直受到阻碍，而这种合作动力学在相干中子散射中是可见的。利用中子极化分析，我们首次能够以前所未有的精度直接测量轻水中的相干中子散射信号。在0.2至1埃的中间范围内，观测到的相干信号增强，这清楚地证明了水中的分子间相互作用延伸到了最近邻分子之间的距离之外。我们的研究揭示了水中存在皮秒级的合作过程，其本质可能与几个水分子的合作重排有关。这个过程可能是与粘度相关的大规模输运的先兆。我们的结果有助于增进对纳米尺度上一般输运机制的理解，这对于生物医学技术或纳米流体装置的开发可能是有用的。
