Radiative decay rates of metastable Ar III and Cu II ions

Magnetic dipole ($M1$) and electric quadrupole ($E2$) lines have been observed from trapped metastable Ar III and Cu II ions. The decay of these lines following excitation has yielded the lifetimes (or total radiative decay rates) for the upper levels. The lines observed are, from Ar III, the $M1$ transition at 3109 {} from ¹S₀ to ³P₁ in the ground state 3p⁴ configuration, and from Cu II, the $E2$ lines at 4377 and 3807 {} from 3d⁹4s ¹D₂ and ³D₂ to the ground state 3d¹⁰¹S₀. The results for the total radiative rates are γ(¹S₀)=9.2±2.3 sec^-1 for Ar III and γ(³D₂)=0.14±0.28 sec^-1 and γ(¹D₂)=1.95±0.24 sec^-1 for Cu II. These results are compared to existing theoretical values.