Features of the Excitation of Principal Series Lines of Atoms of the Zinc Subgroup by an Electron Impact: I. Cadmium

Using the technique of intersecting beams of slow electrons and atoms of cadmium, excitation functions of three spectral lines of its principal series (166.9, 152.7, and 146.9 nm) originating from the 5snp levels (n = 6, 7, 8, respectively) are measured. In the electron energy range of 12-18 eV, the manifestation of the postcollision interaction of slow scattered electrons and fast electrons ejected with the decay of autoionization states has been revealed on these functions. This process leads to an additional population of the initial levels of spectral transitions and, correspondingly, to maxima in the excitation functions due to the capture of a scattered electron into these excited levels at incident electron energies of similar to 11.8, similar to 12.4, and similar to 16.6 eV. The terms of atom autoionization states responsible for the observed maxima in excitation functions of spectral lines are determined. The effective widths of the electron decay of autoionization states the combined action of which leads to the energy shift of maxima is estimated in the classical approximation in two ways-by direct calculations and by the least squares approximation. Calculations are performed using approximate formulas valid for different relations between the postcollision shift of maxima in the excitation functions and the bonding energy of the atomic levels.