Energies and Lifetimes of Doubly Excited States in He i

Abstract

Using the beam-foil technique we have observed radiative transitions between doubly excited states of He i. From previous calculations, we have been able to classify many of these transitions. Some of the lifetimes of the upper states were obtained from decay-time measurements. There is good agreement between theory and experiment for both wavelengths and radiative lifetimes. A transition between doubly excited states in Li ii has also been observed, and we compare experiment and theory for higher members of the He i isoelectronic sequence.