Penning Ionization of Ar and N2by He(23S) and Excitation Transfer from Ar(1.3P) to N2

Abstract

Chemi-ionization cross sections of Ar and N ₂ by He(2 ³ S) and excitation transfer cross sections from the first excited configuration of Ar to N ₂ have been measured by monitoring emissions from N ₂ at 600 K. Helium and argon atoms are excited by an electron beam of energy close to the energy of the level concerned and any contributions from higher excited states can be excluded. Cross sections obtained are 9.4 _+1.3 ^-1.7 , 7.9 _-0.7 ^+1.2 , 29 _-3 ⁺⁵ and 8.7 _-0.8 ^+1.3 Å ³ for He(2 ³ S)-Ar, He(2 ³ S)-N ₂ , Ar( ¹ P ₁ )-N ₂ and Ar( ³ P)-N ₂ , respectively. The values are larger than other measurements at room temperature and are consistent with an energy dependent cross section.