Structure of the Ice Nanocrystal Surface from Simulated versus Experimental Spectra of Adsorbed CF₄

CF 4 adsorbate uptake and spectra are simulated on various model icy surfaces and compared to experimental data measured for CF 4 adsorbate on ice nanocrystals. Comparison suggests that surfaces of annealed ice nanocrystals are relatively smooth but laterally disordered, while surfaces of unannealed nanocrystals are disordered and rough. CF 4 adsorbate structure and uptake display remarkable sensitivity to the structural features of the ice surface models and in particular to the extent of disorder. Asymmetric CF stretch spectroscopy of CF 4 adsorbate is suggested as a useful probe of the surface structure of molecular solids and of large molecular clusters.