Scattering of Low-Energy H— Ions in Helium, Neon, and Argon

Abstract

Elastic and inelastic cross sections have been measured for the scattering of H— ions in helium, neon, and argon gases, at incident ion energies in the range 5 ev to 350 ev. One term interaction potentials of the form V=—K/rn were calculated from the low-energy elastic cross sections. These potentials were: for H— and He, V=—2.90/r3.01 ev for r=1.30 A to 1.90 A; for H— and Ne, V=—4.17/r2.80 ev for r=1.00 A to 1.78 A; and for H— and A, V=—7.82/r3.40 ev for r=1.23 A to 2.12 A. The observed inelastic cross sections are interpreted as cross sections for electron detachment from H—; they show a similar behavior with ion energy W in the three cases, appearing at W between 0 and 5 ev, rising rapidly to W=40 ev, and then rising very slowly to W=350 ev. Evidence was found for positive ion formation in H— collisions with Ne and A atoms at ion energies above 100 ev.