Systematic trends in atomic transition probabilities in neutral and singly-ionized zinc,cadmium and mercury

The beam-foil technique has been used to measure mean lives of excited levels in neutral and singly ionized zinc, cadmium, and mercury. In the neutral atoms, the lifetimes measured were in good agreement with those obtained by the Hanle-effect and phase-shift techniques, but discrepancies were found in some of the life-times measured by the delayed-coincidence method. For singly ionized zinc and cadmium, six mean lives have been measured, while seven were obtained in singly ionized mercury. For the ionized species, systematic trends show that some of the results recently obtained by the phase-shift method may be in error. The mean lives reported were converted to ; values for transitions for which reliable multiplet intensity ratios are available. The ; value systematics show that for the same type of spectral transition, identical ; values have been obtained within homologous atoms.