We have investigated the S-wave resonance states in positron-hydrogen system embedded
in dense quantum plasmas using Hylleraas-type wave functions within the framework of the …

The dipole and quadrupole polarizabilities (both static and dynamic) of negatively charged
helium‐like ions are investigated. The mass dependence of the polarizability is studied by …

We investigate the bound 1, 3 D states and the doubly-excited 1, 3 D e resonance states of
two-electron positive ions Li+ and Be 2+ by employing correlated exponential wave …

The effect of plasma screening on the dynamic dipole polarizability (DPP) of two‐electron
ions Be2+, B3+, and C4+ has been investigated using highly correlated exponential wave …

In view of the analogy of an exciton, biexciton and trion to the positronium (Ps) atom, Ps
molecule, and Ps negative ion, in this chapter, we review our recent works on the Ps atom …

We investigate the influence of model plasma environments on the tune-out wavelengths for
helium-like ions based on the Debye–Hückel shielding approach to plasma modeling. The …