Excitation ofBe+by electron impact

Calculations of the collision strength for excitation of the $2p$ state of ${\mathrm{Be}}^{+}$ are performed at incident energies of 2, 5, and 8 Ry. A modified five-state close-coupling expansion is used in which three pseudostates $\overline{3}\overline{s}$, $\overline{3}\overline{p}$, and $\overline{3}\overline{d}$ 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.