Doubly-excited Terms in Lithium and Beryllium

Abstract

in an isotope separator to energies between 25 and 85 keV and sent through a carbon foil. The light emitted by the foil-excited particles was analyzed either with a 2 meter Jarrell-Ash monochromator equipped with an EM1 6256 photomultiplier (2 000-Doubly-excited terms in lithium and beryllium.

The quartet levels of lithium

“…In table 3, the hybrid values of the wavelength for 1s2pnd 4 D o -1s2p2p 4 P are also shown in parentheses by using the energy of 1s2p2p 4 P, given by Hsu et al (1994). They are in good agreement with the experimental results (Berry et al 1971, 1972, Bromander et al 1979, Mannervik 1981, Mannervik and Cederquist 1983.…”

Lifetimes of lowest even-parity quartet levels of three-electron ions

“…For Be II the two experimental results differ by far more than their claimed errors. The result obtained by Berry et al [14] comes close to the trend of the 4P1/2.3/2 data where- [14] (because of the spatial resolution of the spectrometer perhaps), and in [-13] the steepest-slope theorem was employed to assume the shortest-lived decay component to be the wanted one, the two data sets might be interpreted as referring to different finestructure levels of the unresolved multiplet. However, none of those early studies mentions such considerations, and a careful remeasurement may be called for.…”

Radiative lifetimes, branching fractions, and oscillator strengths of some levels in Be I

“…With the beam-foil technique, the lifetimes for the series 2s n d 1 D ( n = 3-6) in Be I were measured, and oscillator strengths for the transitions down to 2s2p 1 P o were determined by Andersen et al in 1971 [7] . In the same year, Berry et al measured the lifetime of the 2p3p 3 P state using the beam-foil technique [8] . With the same technique, lifetimes of eight Be I terms, seven of which are located above the ionization limit, were determined by Hontzeas et al in 1972 [9] .…”