Metastable autoionizing three- and four-electron states in beryllium

Abstract

A group of metastable autoionizing levels in beryllium has been observed after Be+ ion bombardment of 7 mu g cm-2 thin carbon foils at 300 keV incident ion energy. Two peaks appearing at 102.7 and 106.7 eV are interpreted to be related to the Auger decay of the Be I(1s2s2p2) 5Pe term. Lifetimes of the (1s2p 2) 4Pe state in Be II and the (1s2s2p2) 5Pe state in Be I have been determined. Different decay mechanisms are discussed.