Helium Afterglow. II. Molecular Spectrum

Abstract

Spectroscopic investigation of a flowing helium afterglow revealed the presence of strong bands of He₂. An examination of the axial variation and pressure dependence of the intensity of the emission and He₂⁺ concentration, as evidenced by titration, served to identify the dominant reaction populating the excited molecular states as being the collisional—radiative recombination of He₂⁺.