On the mechanism of the electron-impact excitation of 4d95s22D5/2, 3/2 upper laser levels in cadmium ions

The energy dependence of the effective cross sections for the electron-impact excitation of 4d95s22D5/2, 3/2 − 4d105p2P12, 3/2/0 laser transitions in cadmium ions was studied by a high-precision spectroscopic technique using crossed electron and ion beams. The absolute effective cross sections for the laser line excitation at λ=441.6 and 325.0 nm have the peak values 2.5× 10−16 and 1.3×10−16 cm2, respectively. It is shown that population of the 4d95s22D5/2, 3/2 upper laser levels by the electron impact on cadmium ions in the 4d105s2S1/2 ground state takes place predominantly due to the resonance processes; that is, it proceeds via atomic and ionic autoionization states.