Selective formation of ${\mathrm{He}}^{+}$($n=3\mathrm{}$) in ${\mathrm{He}}^{2+}$-Li collisions

Excited-state formation in inelastic ${\mathrm{He}}^{2+}$-Li collisions at kinetic energies up to 7 kev (center of mass) has been diagnosed by dispersal and detection of both visible and soft x-ray radiation emanating from the intersection of ${\mathrm{He}}^{2+}$ and Li beams. The theoretical predictions of Shipsey et al., that ${\mathrm{He}}^{+}$($n=3\mathrm{}$) is preferentially formed, are found to be valid. The cross section for this selective process is sufficiently high to support the suggested application for production of super-radiance at the He ii Lyman $\alpha$ and Lyman $\beta$ wavelengths, 304 Å and 256 Å, respectively.