SOLVATION OF HYDROCHLORIC-ACID IN PROTONATED WATER CLUSTERS

The reactions of protonated water clusters H+(H2O)(n),n approximate to 1-50, have been investigated in an FT-ICR instrument under single collision conditions. Collisions with ambient temperature argon result in fragmentation and eventually formation of the n=4, hydrated hydroxonium cation. With hydrochloric acid the smaller clusters fragment, larger ones also exchange ligand. Clusters having n greater than or equal to 11 can exchange one, and n greater than or equal to 17 two, water molecules for HCl. Implications for stratospheric chemistry are discussed.