Quenching collisions of low-energy metastable multiply charged argon ions

Quenching rates have been measured for selected metastable levels of Arq+ ions (q=2, 3, 9, and 10) stored in a Kingdon ion trap, with mean energies of 262q eV and 181q eV. Effective quenching cross sections derived from these rates are found to be comparable to electron-capture cross sections of Arq+-Ar collisions studied independently using ion-beam techniques. This implies that quenching is dominated by electron-capture collisions which change the ion charge state