Photodetachment of the Positronium Negative Ion with Exponential Cosine-Screened Coulomb Potentials

We have made an investigation to study the photodetachment of positronium negative ion (Ps ⁻) interacting with exponential cosine-screened Coulomb potentials (ECSCP) within the framework of dipole approximation. The dipole transition matrix elements are calculated using the asymptotic form of highly accurate initial wave function of the bound ionic state and plane wave for final electron–positronium state. Results for photodetachment cross section in ECSCP are reported for the screening parameter in the range 0.0,0.35] (in a₀^-1{a_0^{-1}}). Our results for the unscreened case agree nicely with some of the most accurate results available in the literature. Furthermore we make a comparative study of the photodetachment of Ps ⁻ in ECSCP with the photodetachment of Ps ⁻ in screened Coulomb potential. To the best of our knowledge, such a study on the photodetachment of Ps ⁻ in ECSCP is carried out for the first time in the literature.