Is the H₂OCl⁺ Ion a Viable Intermediate for the Hydrolysis of ClONO₂ on Ice Surfaces?

The involvement of the H 2 OCl + ion in the ClONO 2 hydrolysis on an ice surface is shown to be unlikely via quantum chemical calculations and comparative analysis of infrared spectra of low temperature mixtures of H 2 O with HNO 3, N 2 O 5 or ClONO 2 . For the ClONO 2 hydrolysis on ice, the reaction path involving H 2 OCl + is estimated to be ∼10−14 kcal/mol higher in energy than the one involving H 3 O + via proton transfer in the ice lattice. An analysis of literature infrared spectra, complemented by quantum chemical calculations of the vibrational frequencies of the relevant species, indicates that the spectral feature previously assigned to H 2 OCl + should instead be assigned to molecular HNO 3 .