Ionization of Hydrogen Atoms in Slow Collisions with Metastable Helium Atoms He* (2¹S, 2³S)

Ionization cross sections of Hydrogen atoms by collisions with metastable Helium atoms are calculated on the basis of the local complex potential method. Complex potentials are estimated by the valence bond ( VB ) method. The results show that the cross sections for He * (2 1 S )+H and He * (2 3 S )+H are 1.27 a 0 2 and 129 a 0 2 , respectively, at the energy of relative motion 0.001 a.u. and that the temperature dependence of the reaction rate in the former case (∼ T 1.0 ) is more remarkable than that in the latter (∼ T 0.1 ). It is found that the real part of the complex potential plays an important part in these processes.