Optical Ionization-Excitation Functions of Zinc, Cadmium, and Mercury by Electron Impact

The cross sections for the production of 16 lines of the Zn(II), Cd(II), and Hg(II) spectra by ionization‐excitation collisions between electrons and neutral atoms have been measured over the energy range0–260eV. The spectral lines are characterized by optical excitation functions which reach their maximum values within the energy range 40–90 eV, and by emission cross‐section values of approximate, 10⁻¹⁷–10⁻²⁰ cm² at 200 eV. Theoretical branching ratios have been calculated and are used with the experimental data to obtain estimates of the $7^2{S}_{\text{1/2}}$ (Hg⁺), $6^2{S}_{\text{1/2}}$ (Cd⁺), and $5^2{S}_{\text{1/2}}$ (Zn⁺) direct excitation cross sections. Corresponding theoretical cross sections are estimated by means of the Born approximation. The cross‐section ratios ${\mathrm{Q(n}}^2{P}_{\text{1/2,3/2}}{\mathrm{)\hspace{0.17em}/\hspace{0.17em}Q(n}}^2{D}_{\text{5/2}})$ are calculated for ${\mathrm{Zn}}^{+}\text{(n\hspace{0.17em}=\hspace{0.17em}5)}$ , ${\mathrm{Cd}}^{+}\text{(n\hspace{0.17em}=\hspace{0.17em}5)}$ , and ${\mathrm{Hg}}^{+}\text{(n\hspace{0.17em}=\hspace{0.17em}7)}$ , and the results compared with experiment.