Surface Vibrational Spectroscopic Study of Surface Melting of Ice

Surface melting on the (0001) face of hexagonal ice ( ${\mathrm{I}}_h$) was studied by sum-frequency vibrational spectroscopy in the OH stretch frequency range. The degree of orientational order of the dangling OH bonds at the surface was measured as a function of temperature. Disordering sets in around 200 K and increases dramatically with temperature. The results show that the disordered (quasiliquid) layer on ice is structurally different from normal liquid water.