Lyman-αemission in collisions ofH+ions with Na(3s) and laser-excited Na(3p) atoms

We report on an experimental study of Lyman-α emission from H(2p) capture processes in collisions between ${\mathrm{H}}^{+}$ ions and Na(3s) as well as laser-excited aligned Na(3p) atoms. The impact energy lies between 0.5 and 10 keV. We observe a strong enhancement of capture from Na(3p) over capture from Na(3s), in agreement with recent calculations by R. Allan et al. and W. Fritsch, but at variance with earlier experimental and theoretical results (V. S. Kushawaha et al. and M. Kimura et al.).