Energies and autoionization widths inthe lithium iso-electronic sequence

Abstract

Energies and autoionization widths are presented forautoionizing states in Li I, Be II and B IIIlying between the 1s2 and the 1s2s 3S ionization limits. A configuration interaction expansion combined with a B-splinebasis set has been used to compute the properties of thelowest 2Se, 2Po and 2Destates which are, in the LS approximation, the only termsallowed to autoionize. The comparison with theoretical andexperimental data shows the high accuracy of the presentapproach applied to singly core-excited states. The error on theenergies is found, in the case of Li I, to be well below10 meV in general, while for Be II and B III, forwhich much less is known, the present results point to the needfor more accurate measurements. Several new identificationshave been made and some identifications revised in theexperimental data. For autoionization widths, the comparisonwith experimental and theoretical data shows that themonoconfigurational HF description of the 1s2 limit employedhere provides a good approximation although, for Li I, someof the differences with experimental measurements can be relatedto the lack of correlation in the wavefunction used to describe the limit.