Postcollision interaction upon electron excitation of the 5sns 1 S 0 and 5snd 3 D j levels of the cadmium atom

The optical excitation functions (OEFs) for two series of spectral lines of the Cd atom originating from the 5sns ¹ S ₀ (n = 6?11) and 5snd ³ D _{1, 2, 3} (n = 5 and 6) levels excited by an ultramonoenergetic (ΔE _1/2 < 0.05 eV) electron beam with energies exceeding the single ionization threshold are presented. In the energy range from 10.8 to 12.9 eV, the energy dependences of the excitation cross sections of the studied spectral transitions exhibit the effect of postcollision interaction of slow scattered and fast emitted electrons. This process leads to an additional population of the initial levels of the spectral transitions due to the capture of a scattered electron into an excited atomic level. The energies and widths of the electronic decay of autoionizing states are estimated in the classical approach by two methods, namely, by the least squares method and by direct calculation. Calculations are performed using approximate formulas valid for different relations between the postcollision shifts of the OEF maxima and the binding energies of the atomic levels. The terms of the autoionizing atomic states responsible for the maxima observed in the OEFs of the spectral transitions are determined.