Angular Distribution of Photoelectrons. I. Cadmium and Zinc Atoms at 584 and 1048 Å

The distribution of photoelectron trajectories has been measured with unpolarized resonance emission from helium and argon, modulated atomic beams of cadmium and zinc, a sector-focusing photoelectron energy analyzer, and digital counting and demodulation techniques. The autoionizing transitions at 1048 Å to produce Cd+S1/2 and Zn+S1/22 and the direct ionization at 584 Å to produce Cd+D5/22 all result in electron-trajectory distributions which are close to cos2θ with respect to the electric vector of the radiation. Ionization at 584 Å to produce Cd+D3/22 results in an isotropic distribution. For cadmium the ratio of total cross sections to produce D5/22 / 2D3/2is 1.06 ± 0.07.