jp8b07480_si_001.pdf (480.05 kB)
Ice Nucleation at the Water–Sapphire Interface: Transient Sum-Frequency Response without Evidence for Transient Ice Phase
journal contribution
posted on 2018-10-10, 00:00 authored by Ahmed Abdelmonem, Ellen H. G. Backus, Mischa BonnHeterogeneous
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.