Beam-laser lifetime measurements for low-lying quartet states in Fe ii

Radiative lifetimes for seven levels of the z ${}_{}{}^4{}_{}{}^{}\mathrm{°}$, ${}_{}{}^4{}_{}{}^{}$D°, and ${}_{}{}^4{}_{}{}^{}$F° terms of Fe i i have been measured by using laser excitation of a beam of fast ${\mathrm{Fe}}^{+}$ ions. The ratio of the measured lifetime to that calculated from Kurucz’s gf values appears to increase systematically with the energy of the levels involved.