Low Energy Collision Experiments using the Beam Guide Technique:

Charge Transfer Cross Sections of Ar³⁺ and Kr³⁺ in their own Gases

Abstract

The trajectories of charged particles moving in an octopole ion beam guide (OPIG) are computer-simulated for various initial conditions of motion. Boundary conditions between the stable and unstable regions of beam trajectory in OPIG are obtained. These calculated results are very useful for operation of OPIG under the best condition.
In low energy collision experiments using the beam guide technique, cross sections of one -, two- and three-electron capture processes in collision systems of Ar³⁺-Ar and Kr³⁺-Kr are measured in energy region from 0.375 to 768 eV in center-of-mass system. In both collision systems, one-electron capture reaction is predominant in higher energy side, however, the dominant reaction changes from one-electron capture reaction to the symmetric resonant three-electron capture reaction in the low energy region below about 10 eV. As was predicted, it was first confirmed that each cross section obtained for symmetric resonant triple-charge -transfer reaction of Ar³⁺ and Kr³⁺ at the low energy end of Ecm = 0.375 eV is larger than both cross sections of symmetric resonant double-charge-transfer for the doubly charged ion and symmetric resonant single-charge-transfer for the singly charged ion.