Interference effects in negative ion formation

This paper presents recent data on differential cross sections for H- formation from collisions of H+ and H0 with Ar in the energy range 1.0 to 4 keV. Experimental data exhibit a sharp maximum at 00 scattering angle as well as an oscillatory structure. The functional form and scaling properties strongly indicate that there is a glory maximum which occurs when the classical deflection function changes over from attractive to repulsive at some finite impact parameter. The oscillations are predicted by the Bessel function and may be said to arise from interference of the contributions from the two branches of the deflection function near to a glory