Single-and-double electron loss of O2+ in collisions with argon and helium

This paper reports that the ratios of double to single electron losscross-section (R) of O²⁺ in collision with Ar and He at thevelocity of 1--4nu₀ (nu₀ is the Bohr velocity) have beenobtained by the coincidence technique. The trend of R-V in theexperiment indicates that the effective charge varies with injectedvelocity. The effective charge can be obtained by the n-bodyclassical trajectory Monte Carlo method, which is interpreted by themolecular Coulomb over barrier model.