Adsorptions of HOCl on ice surface: Effects of long-range electrostatics, surface heterogeneity, and hydrogen disorders of ice crystal

The adsorptions of HOCl on ice surface were studied with the help of QM/EFP scheme. HOCl binding energies were predicted to be -12.2 to -17.8 kcal/mol (BSSE corrected values) depending on surface absorption sites. These values are much larger than previous quantum mechanical estimations but are rather in good agreements with experiments and MD study. Structurally, various new surface binding configurations of HOCl, including an unusual penta coordination, were found indicating diverse reacting environments of ice surface. In general, it was found that the ice surface itself as well as HOCl adsorptions are strongly affected by long-range electrostatics, surface heterogeneity and hydrogen disorders of bulk ice, revealing the unique characteristics of ice surface as a reacting environment. As a way of modeling ice surface, we demonstrated that the hybrid QM/EFP scheme is very effective.