Metastable decay of propane (CH 3CD 2CH 3)- and argon/propane-cluster ions induced by isomerization of a propyl ion core and fragmentation patterns of propane ions in the cluster environment

Abstract

Metastable decay processes occurring in neat propane and argon/propane cluster ions with a propyl ion core have been further investigated using partially deuterated propane, CH 3CD 2CH 3. It is concluded that the previously described metastable decay channel leading to the evaporation of up to four monomers is induced by isomerization of the corner-protonated cyclopropane ion to the 2-propyl cation via a transient 1-propyl ion. A considerable decrease of the relative abundance of fragment ions upon electron impact ionization is observed when going from the monomer propane to the cluster environment (C 3H 8 or Ar). This suppression of the unimolecular decay of the clustered propane ions may be rationalized by energy transfer from the ion to the surrounding cluster environment and by cage recombination processes of the dissociating fragments.