LARGE-ANGLE AND SMALL-ANGLE PEAKS IN SLOW H+-H COLLISIONS

The probability against impact-parameter curve for H(2p) production in slow H+-H collisions is considered with particular reference to its double-peak structure The inner large-angle peak has already been described by Bates and Sprevak (1970) in simple physical terms, as strong rotational coupling at the point of closest approach on a Coulomb trajectory. The outer small-angle peak is now simply described in terms of an approximate 2p sigma -2p pi symmetrical resonance arising out of perturbed-united-atom degeneracy. Both peaks are encompassed by one of the authors' previously proposed phase-integral formulae.