Oscillator-strength systematics for low-lying transitions in multiply charged ions

Abstract

The foil-excitation technique has been used to study atomic lifetimes in a number of homologous atoms with ionic charges up to six. It was observed that even at moderate initial ion energies (approx. 500 keV), some low-lying levels in multiply charged ions are populated with sufficient intensity for lifetime measurements. The relatively low initial ion energies facilitate the spectral-line identification, so line broadening seems to be a minor problem compared to higher initial ion energies. Systematic trends in the ƒ- values derived from the lifetime measurements for n 2S− n 2P and n 2P− n 2D transitions in the Cu I, Ag I and Au I isoelectronic sequences are discussed and compared with earlier measurements for homologous atoms with lower masses. From the present results, ƒ- values for transitions which can not be measured experimentally due to line blending, are derived by interpolation. An extrapolation of the present ƒ- values allows a determination of ƒ- values in highly charged ions with reasonable accuracy.