Relativistic Energies and Auger Widths of High-Lying Doubly-Excited States 1s²3lnl'¹D^e in Be-Like O⁴⁺ Ions

The saddle-point variational method and restricted variational method are used to calculate energies of doubly-excited singlet states 1s²3lnl' (n=3-5) ^1_De in Be-like O⁴⁺ ions, including the mass polarization and relativistic corrections. The saddle-point complex-rotation method is used to compute the Auger widths and Auger transition rates. These results are compared with other theoretical and experimental data in the literature.