2D-IR correlation and principle component analysis of interfacial melting of thin ice films

The interfacial melting of a thin film of ice (15 nm thick) grown on the surface of a Ge prism is probed with attenuated total reflection infrared spectroscopy. Extinction spectra are collected as the ice is heated from −23 to 0 °C. Moving window correlation and principle component analysis reveal a transition between different growth regions at −1 °C. The temperature dependence for the thickness of the interfacial interface is compared to theoretical models where a similar transition is postulated to occur for a small amount of impurities at the ice/vapor interface.