Radiative Lifetimes from Ultraviolet Lines of Ne I, Ne II, and Ne III

The electron-excitation, phase-shift apparatus of Lawrence has been applied to the determination of radiative lifetimes of Ne I, Ne II, and Ne III states via transitions in the untraviolet. With the exception of the Ne II 462 Å resonance transition, the measured transitions lie in the wavelength range 2000 to 3800 Å. Stages of ionization were separated by varying the energy of the electron beam between 60 and 215 V. Eight Ne I radiative lifetimes in the series $\mathrm{np}\to 3s$, where $n=4-7\mathrm{}$. have been measured using ten lines in the 2775 to 3634 Å region; the lifetimes range from 51 to 335 nsec. In Ne II, ten lifetimes between 2.1 and 10.1 nsec have been measured for quartet and doublet states radiating in the 2095 to 3777 Å region, as well as for the $2p^6{}_{}{}^2{}_{}{}^{}S_{}^0{}_{}{}^{}$ state (462 Å transition). Finally, eight radiative lifetimes of Ne III states ranging from 1.2 to 6 nsec have been studied via transitions in the 2065 to 2680 Å interval. Assignment of three lines, previously unclassified with respect to ionization species, has been unambiguously made using the electron-beam source.