Electron affinities of Si, Ge, Sn and Pt by tunable laser photodetachment studies

The electron affinities of silicon, germanium, tin and platinum are measured by tunable laser photodetachment spectroscopy via detection of the neutral atomic species. The binding energy values obtained for and (electron configuration with n = 3 to 5) are and , respectively. The improvements in accuracy over the existing values in the literature for these three species lie between one and two orders of magnitude. The binding energy of the ground level of is found to be . This result is in relatively good agreement with the two existing results in the literature. Finally, the prospects for further studies of atomic negative ions are briefly discussed.