Photon Emission from Core-Excited Be I and Be II States

Optical-emission spectra of core-excited Be I 5 L and core-excited Be II 2 L and 4 L states have been studied by means of the beam-foil-excitation method. Multiconfigurational Hartree-Fock calculations have been performed for the optical transitions between the lower-lying Be I 5 L states and between 1 s 2 pnl ( n = 2-4, l = 0-3) 2 P 0 , 2 P e , 2 D 0 , 2 D e , and 2 F e states in core-excited Be II 2 L to facilitate the identifications. Some previously assigned core-excited Be II 4 L transitions are shown to belong to either the core-excited Be I 5 L or the core-excited Be II 2 L spectrum. Additional identifications of core-excited Be II 2 L transitions explain the main features of this spectrum. The identifications of Be II 1 s 2 p 4 l 4 L states are discussed.