Excitation of Light in Hydrogen and Helium by Hydrogen Ions

Abstract

The light excited when protons or ${\mathrm{H}}_{2}^{+}$ ions pass through hydrogen or helium with kinetic energies of 2000 ev has been observed. Contamination of the beam by stray particles has been eliminated by electrostatic deflection and magnetic mass separation. The light is almost entirely due to the Balmer spectrum. Relative cross sections for the excitation of ${\mathrm{H}}_{\ensuremath{\alpha}}$ by protons and ${\mathrm{H}}_{2}^{+}$ impinging on ${\mathrm{H}}_{2}$ and He have been determined.