Extrema in the generalized oscillator strengths of the resonance transitions in zinc and cadmium

The generalized oscillator strengths of the transitions 4 1 S-4 1 P in zinc and 5 1 S-5 1 P in cadmium have been studied at 255 eV incident electron kinetic energy over an angular range 3 degrees to 20 degrees . The data have been placed on an absolute scale by normalizing to the optical oscillator strength. The first non-zero minima were observed at ( Delta P) 2 =1.0 au and 0.8 au, for zinc and cadmium, respectively. The positions of the second maxima were found to be ( Delta P) 2 =1.5 au and 1.7 au, for zinc and cadmium, respectively. Comparison is made with theoretical calculations.