Semiclassical transition probabilities for the electron-impact excitation of hydrogenic ions in dense plasmas

Abstract

Plasma-screening effects are investigated on semiclassical transition probabilities for electron-impact excitation of hydrogenic ions in dense plasmas. The electron–ion interaction potential is obtained by a nonspherical Debye–Hückel model of the screened Coulomb interaction for the interesting domain of the Debye length Λ/aZ≥10. Semiclassical straight-line trajectory method is used to describe the behavior of the projectile electron. The screening effect is increased with increasing the projectile energy. The plasma-screening effect on the optically allowed (dipole) transition (1s→2p) is found to be more effective than that on the optically forbidden transition (1s→2s). For 1s→2s transition, the maximum position of the transition probability is almost unchanged with increasing or decreasing the projectile energy and plasma-screening effect. However, for 1s→2p transition, the maximum position of the transition probability has receded from the nucleus as the projectile energy increases.