Doubly Excited States of Beryllium-Like Ions ( $$Z = 4$$ –10) in Dense Quantum Plasmas

The doubly excited states (DES) of beryllium-like ions (BLI) embedded in dense quantum plasma (QP) have been investigated by applying the stabilization method. Ions having atomic number Z lying between 4 to 10 are considered and treated as an effective three-body system by means of the ‘method of model potential’. Exponential cosine screened Coulomb potential is used to describe the screened interactions among the charged particles in QP. Using an extensive wavefunction, it has been possible to detect the existence of one, four and five DESs lying above the \(1s^22p\) threshold in the ions having \(Z = 4\), \(Z = 5\) and \(Z = 6\)–10 respectively. The energies and widths of these states for the plasma-free case agree nicely with the reliable results available in the literature. A detailed study has been made to explore the changes in the energies and widths of these states subject to the varying screening effect of the background quantum plasma environment. Furthermore, Z-dependence of the changes induced by the plasma has also been investigated in detail.