Collision-induced reactions of size-selected cluster ions of Ar

Abstract

The collision-induced reactions of Ar_n ⁺ (n = 2 - 15) with Kr and Ne were studied by use of a tandem mass-spectrometer equipped with octapole ion guides. The results showed that evaporation, charge transfer and fusion were dominant pathways in the reactions. The absolute cross sections and the branching ratios were obtained as functions of the size of the parent cluster ion and the collision energy. The size- and energy dependences were explained in the scheme of the charge-induced dipole and the induced dipole-induced dipole scatterings. It was also shown that the conversion efficiency of the collision energy into the internal energy of Ar_n ⁺ was proportional to the cluster size. In the Ne collision, the upper limit of the conversion efficiency was estimated to be ∼ 60 % at the collision energy of 0.2 eV.