Complex scaling in Lagrange-mesh calculations for Stark shifts and widths of the screened Coulomb potential

In recent years, much attention has been drawn to atomic processes influenced by the screened Coulomb/Yukawa potential. In this work, the influence of the static electric field on screened Coulomb potential is investigated using the complex-coordinate rotation method in Lagrange-mesh calculations. The Stark shifts and half-widths of the ground and excited states of the screened Coulomb potentials are reported for a wide range of field strengths in different screening conditions. Comparisons are made with the available data. While the screening effects lead to the continuum lowering and level splitting phenomena, the Stark effects also cause the shifting and splitting of the energy levels. The competition between the screening effect and the external electric field is demonstrated and discussed. The broadening of the half-width due to the screening and Stark effects is observed.