Abdelmonem Ahmed, Backus Ellen H G, Bonn Mischa
Institute of Meteorology and Climate Research-Atmospheric Aerosol Research (IMKAAF), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
J Phys Chem C Nanomater Interfaces. 2018 Nov 1;122(43):24760-24764. doi: 10.1021/acs.jpcc.8b07480. Epub 2018 Oct 10.
Heterogeneous ice nucleation at the water-sapphire interface is studied using sum-frequency generation spectroscopy. We follow the response of the O-H stretch mode of interfacial water during ice nucleation as a function of time and temperature. The ice and liquid states each exhibit very distinct, largely temperature-independent responses. However, at the moment of freezing, a transient response with a significantly different intensity is observed, with a lifetime between several seconds and several minutes. The presence of this transient signal has previously been attributed to a transient phase of ice. Here, we demonstrate that the transient signal can be explained without invoking a transient ice phase, as the transient signal can simply be accounted for by a linear combination of time-dependent liquid and ice responses.
利用和频振动光谱研究了水-蓝宝石界面的非均相冰核形成过程。我们跟踪了冰核形成过程中界面水的O-H伸缩振动模式随时间和温度的响应。冰态和液态各自呈现出非常独特的、基本与温度无关的响应。然而，在结冰瞬间，会观察到一个强度明显不同的瞬态响应，其寿命在几秒到几分钟之间。此前，这种瞬态信号的存在被归因于冰的一个瞬态相。在此，我们证明，无需引入瞬态冰相就能解释瞬态信号，因为瞬态信号可以简单地由随时间变化的液态和冰态响应的线性组合来解释。
