Rate measurements of reactions of helium metastable species at atmospheric pressures. II. He2 (2 3Σ+u) in pure afterglows

Using resonance absorption spectrometry the rates of the reactions He₂(2 ³Σ⁺_u)+He₂(2 ³Σ⁺_u) →products and He₂(2 ³Σ⁺_u)+Ne→products have been measured in the afterglow period of electron beam excited discharge plasmas in helium at atmospheric pressures. The reported rate for the first reactions at (1.3±0.3)10^-10 cm³ sec^-1 is an order of magnitude lower than previously reported values. A value for the inverse transition probability of the 3 ³Π_g←2 ³Σ⁺_u electronic transition has also been established.