Close-encounter effects on electron-ion s→p oriented excitations in dense plasmas are investigated using a first-order semiclassical straight-line trajectory method. Plasma-screened interaction potential is given by the classical nonspherical Debye-Hückel model. Without using the dipole approximation, the transition probabilities and orientation parameters are obtained, for various Debye lengths and projectile energies. Including the plasma-screening effects, the transition probabilities are increased for 1s→2${\mathit{p}}_{+1\mathrm{}}$ transitions and decreased for 1s→2${\mathit{p}}_{\mathrm{-}1}$ transitions. The close-encounter effects appreciably change the transition probabilities and orientation parameters for small impact parameters. It is found that the 1s→2${\mathit{p}}_{+1\mathrm{}}$ transition probabilities and orientation parameters have minima that correspond to the complete 1s→2${\mathit{p}}_{\mathrm{-}1}$ transitions.

• Received 25 May 1995

DOI:https://doi.org/10.1103/PhysRevE.52.5333