Excitation cross sections of Cd+ ions for the upper and lower states of the Cd II 441.6-nm laser line by electron impact

The excitation cross sections by electron impact from the Cd II ground state to the laser upper state 5s2D522 (Beutler state) and the laser lower state 5p P322 (resonance state) have been measured by using a crossed-beam method of electrons and Cd+ ions and a photoncounting method. The electron-energy region investigated was from the threshold energy (5.8 eV) for the excitation of the 5p P322 state to 20 eV. It has been shown that the excitation cross section for the ionic Beutler state 5s2D522 is of the order of 10-15 cm2 and has a sharp peak near the threshold energy for the excitation. The excitation cross section for the resonance state 5p P322 has also been of the order of 10-15 cm2 and has a relatively broad maximum.