PROTON-TRANSFER REACTIONS AT THE SURFACE OF ICE - HETEROGENEOUS REACTIONS INVOLVED IN STRATOSPHERIC OZONE DEPLETION

Two heterogeneous reactions on an ice surface that are relevant in con nection with stratospheric ozone depletion are discussed theoretically : the hydrolysis of chlorine nitrate, ClONO2, to produce HOCl and HNO3 , and the acid ionization of hydrochloric acid HCl. For the former, a recently proposed proton transfer mechanism actively involving the ice lattice is supported by examination of the ClONO2 hydrolysis energeti cs when proton transfer is prevented. For the latter, a previously pro posed picture of facile HCl ionization at, but not on, the ice surface is supported by the results of a quantum treatment of the proton and of a model investigation of the free energetics of ionization atop the ice surface.