Excitation of low excited states of Ne I and He I byHe++ Ne collisions

Emission cross sections for the resonance lines of Ne I (744 and 736 Å) and He I (584 Å) have been investigated during collisions of ${\mathrm{He}}^{+}$ + Ne at energies from threshold to 9 keV. The threshold of excitation for the channel which dissociates into the upper state of the 736-Å line is 21.7 ± 2.0 eV, and the large modulation depth in the total cross section shows this channel to be strongly coupled at an internuclear separation of 5.3 Å to another excited channel which is presumed to be ${\mathrm{He}}^{*}\left(1s2s\right)+{\mathrm{Ne}}^{+}\left(2\mathrm{}{p}^5\right)$. The onset of excitation of the 744-Å line occurs at 16.3 ± 0.5 eV, and the emission cross section exhibits oscillatory structure which is less pronounced than that of the 736-Å line. Excitation of the 584-Å line appears to occur through several channels.