Low-energy electron scattering from Mg, Zn, Cd and Hg: shape resonances and electron affinities

Measurements of electron scattering at low energy from Mg, Zn, Cd and Hg have been carried out using the electron transmission method. A large shape resonance is observed for each element which we identify with the (ns2np)2P ground state of the negative ion. The electron affinities in eV are found to be Mg(–0.15), Zn(–0.49), Cd(–0,33) and Hg(–0.63) with an error of ±0.03 eV. The results are compared with the available theoretical predictions