EXCITATION OF BE+ BY ELECTRON-IMPACT

Calculations of the collision strength for excitation of the 2p state of Be+ are performed at incident energies of 2, 5, and 8 Ry. A modified five-state close-coupling expansion is used in which three pseudostates 3̄s̄, 3̄p̄, and 3̄d̄ are retained in addition to target states 2s and 2p. Pseudostates are chosen so that, for a given incident electron energy, there is a minimum in the dominant partial-wave collision strength with respect to variation of the range parameter. Collision strengths are obtained which lie a few percent closer to the measurements of Taylor, Phaneuf, and Dunn than do the five-state calculations of Hayes et al. © 1978 The American Physical Society.