Quantum study of the adsorption of small molecules on ice: The infrared frequency of the surface hydroxyl group and the vibrational Stark effect

A periodic Hartree-Fock quantum calculation has been developed for the adso rption of small nonpolar model systems (C2H2, C2H4, O-3, CO, N-2, and Ar) o n ice in order to determine the physical variables responsible for the larg e infrared frequency shifts of the surface hydroxyls. It is shown that the correlation between these shifts and the corresponding interaction energies is not quite convincing. On the contrary it appears that the frequency shi fts are tightly correlated to the variation with adsorption of the local el ectric field along the OH bond thus demonstrating that the dangling hydroxy l frequency is largely governed by the vibrational stark effect. (C) 2001 A merican Institute of Physics.