Two-electron excitation of calcium, strontium, and barium atoms on exposure to electron impact

The absolute effective excitation cross-sections for the spectral transitions of alkaline-earth atoms under the action of electron impact are determined, which correspond to simultaneous excitation of s2-valence electrons. The results were obtained on a setup with intersecting atomic and electron beams. It is established that the effective cross-sections of one- and two-electron excitation of valence subshells into states with the same effective principal and orbital quantum numbers are equal. The results obtained are compared with the available theoretical data.