First-principles study of the infrared spectrum of the ice Ih (0001) surface*

Ice particles catalyze a number of processes relevant to atmospheric and environmental chemistry, and the elucidation of these reactions require knowledge of the ice surface structure. Although it is well known that the structure of bulk ice-Ih is proton disordered, the understanding of the microscopic structure of the ice surface is still limited. Recent theoretical studies $^{1,2}$ suggest that the basal (0001) surface of ice Ih is significantly more proton ordered than the bulk. In this work we compute infrared (IR) spectra of several ordered and disordered models of the (0001) surface of ice, and investigate the sensitivity of these spectra to the microscopic details of the surface structure. In particular we discuss possible signatures of disorder in the computed spectra. [1] D. Pan et al., Phys. Rev. Lett. 101, 155703 (2008); [2] V. Buch et al., Proc. Natl. Acad. Sci. U.S.A. 105, 5969 (2008)