The Vapor Pressure of Supercooled Water Measured Using Infrared Spectroscopy

We present measurements of the vapor pressure of supercooled water utilizing infrared spectroscopy, which enables us to verify unambiguously the fact that our data correspond to the vapor pressure of liquid water, not a mixture of liquid water and ice. Our values of the vapor pressure and derived value of the latent heat of vaporization are in agreement with previous work. Below -13 °C, the water film which we monitor to determine coexistence of liquid water (at one temperature) and ice (at another, higher, temperature) de-wets from the hydrophilic silicon prism employed in our apparatus. The de-wetting transition indicates a quantitative change in the structure of the supercooled liquid.