Excitation into 3p⁵5p levels from the metastable levels of Ar

Measurements of cross sections for electron-impact excitation out of the J=0 and J=2 3p⁵4s metastable levels of argon into nine of the ten levels of the 3p⁵5p manifold are presented in the energy range from threshold to 10 eV. A mixed target of atoms in both metastable levels was created by a hollow cathode discharge. Laser quenching was used to depopulate either one of the metastable levels, allowing separate measurements of the cross sections from each of the two metastable levels. Unlike the metastable excitation cross sections into 3p⁵4p levels, the cross sections into the 3p⁵5p levels are not found to be proportional to optical oscillator strengths.