Microsolvation of HCl within cold NH3 clusters.

The solid state solvation of HCl molecules with small ammonia clusters at an average temperature of 100 K was investigated by on-the-fly molecular dynamics methodology. Structures close to the proton jump from HCl molecule to the ammonia have been further checked with the MP2/aug-cc-pvDZ calculations. Ionization of HCl and/or sharing of the proton were found. Two Zundel-type ions were observedone with proton being shared between ammonium ion and Cl (-) anion (Cl (-)...H (+)...NH 3) in all complexes, and the second, between hydrogen chloride and Cl (-) anion in the HCl...Cl (-)...NH 4 (+)...(NH 3) 2 complex. However, in contrast to methanol clusters, ammonia clusters are not good for the proton wires since once the proton moves to ammonia, it is localized on the ammonium ion units.