Screening modification on the trajectory of the projectile electron in the electron--ion excitation in dense plasmas

A behavior of the trajectory of the projectile electron in the electron-impact excitation of hydrogenic ions in dense plasmas is investigated using modified hyperbolic-orbit method in the semiclassical approximation. The interaction potential is obtained by the Debye--Hueckel model of the screened Coulomb interaction for the interesting domain of the Debye length Λ/aZ≥10. The screening effects on the eccentricity of the projectile path produce a significant change in the excitation cross section near excitation threshold. The result shows that the trajectory of the projectile electron becomes a hyperbolic path rather than a parabolic path because of the plasma-screening effects. For higher incident energies, the plasma-screening effects on the projectile electron are decreased