AI 中文总结
该研究通过分子动力学模拟，探究了223 K和265 K下甲醇、丙酮吸附于Ice-Ih基面对冰表面QLL、氢键及SFG信号的影响，为解释相关实验现象提供了机制。
AI 中文摘要
Yettapu、Manning和Cyran近期针对冰/蒸气界面开展的实验工作显示，在223 K温度下，当丙酮或甲醇吸附到冰上时，~3170 cm⁻¹处的 sum frequency generation（SFG，和频产生）信号会发生变化，他们将该信号的变化与冰晶体的诱导熔融关联起来。我们针对他们的实验开展了分子动力学模拟，模拟中采用甲醇和丙酮层吸附在质子有序Ice-Ih（Ih型冰）晶体的基面上，温度设置为223 K和265 K。准液体层（QLL）的宽度、O-H键频率、计算得到的SFG信号以及氢键统计数据均表明，吸附质的存在会引发相关变化。尽管我们未观测到基于吸附质的QLL形成的显著差异，但发现在223 K时，丙酮会保留配位不足的水分子，这些水分子与具有低频O-H键的次级水分子相关联；而甲醇则更充分地融入氢键网络，导致O-H键频率的分布更窄。这种氢键的变化会产生电场的局部修饰，可能对低频下实验SFG信号的差异产生贡献。
英文摘要
Recent experimental work carried out by Yettapu, Manning, and Cyran on ice / vapor interfaces revealed changes in sum frequency generation (SFG) signals at ~ 3170 cm$^{-1}$ depending on whether acetone or methanol was adsorbed onto the ice at 223 K. They linked the transformation of that signal to the induced melting of the ice crystal. We present molecular dynamics modeling of their experiments using methanol and acetone layers adsorbed on the basal facet of a proton-ordered Ice-Ih crystal at temperatures of 223 K and 265 K. The width of the quasi-liquid layer (QLL), O-H bond frequencies, calculated SFG signals, and hydrogen bonding statistics all indicate changes due to the presence of the adsorbates. While we see no significant adsorbate-based differences in QLL formation, we find at 223 K that acetone preserves under-coordinated waters that are associated with a secondary water with a low frequency O-H bond, while methanol integrates more fully into the hydrogen bonding network, resulting in a narrower distribution of O-H bond frequencies. This change in hydrogen bonding produces a local modification of the electric field, which may contribute to the difference in the experimental SFG signals at low frequencies.
Journal refJ. Phys. Chem. C (2026) 130(28), 9932-9941
